CONTROL OF AIRWAY MOTOR NEURONS DURING SLEEP/WAKEFULNESS

Jerome M Siegel, Professor
Brain Research Instituteuniversity Of California Los Angeles
office Of Research Administration
los Angeles, Ca 90095

Grant 5P50HL060296-05 from National Heart, Lung, And Blood Institute, IRG: ZHL1

Abstract: The loss of upper airway muscle tone in sleep is the precipitating cause of sleep apnea. Sleep apnea affects 3-5% of men over 40 and 1.5-2.5% of post-menopausal women. It causes persistent sleepiness, exacerbates a variety of medical conditions and increases morbidity and mortality. We will study how forebrain sleep induction mechanisms cause the reduction of muscle tone in airway dilators. A variety of complementary techniques will be used in sleep apnea patients to determine which forebrain and brainstem regions are activated and inactivated during airway obstruction. In projects 2 and 3 the pathways from forebrain sleep inducing regions will be traced to the brainstem region activated and inactivated in sleep apnea, focusing on regions controlling upper airway muscle tone. These studies will use anatomical tract tracing techniques, thermal activation of sleep controlling neurons and unit recording in the posterior hypothalamus, periaqueductal gray and medulla of unrestrained animals. In projects 4 and 5 we will determine which amino acid and monoamine transmitters mediate the suppression of muscle tone in airway dilator motoneurons during REM and non-REM sleep. These studies will use in vivo microdialysis, intracellular unit recording and iontophoresis. This program will bring basic science techniques to bear on the important clinical problem of sleep apnea. Pilot studies for this collaborative enterprise have already yield data that will produce a major revision in our understanding of the mechanisms controlling the airway during sleep. The work of this SCOR (Specialized Center of Research) will increase our understanding of sleep apnea. It is also likely to be of importance to other disorders of motor control during sleep. It is also likely to be of importance to other disorders of motor control during sleep, including REM sleep behavior disorder, bruxism, periodic limb movements during sleep and cataplexy. This research will also shed light on the cellular mechanisms controlling REM and non-REM sleep states

Keywords: sleep, sleep apnea

Project start date: 1998-09-01

Project end date: 2003-08-31

5P50HL060296-05 (2002): $1477598

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CONTROL OF AIRWAY MOTOR NEURONS DURING SLEEP/WAKEFULNESS

Jerome M Siegel, Professor
Brain Research Instituteuniversity Of California Los Angeles
office Of Research Administration
los Angeles, Ca 90095

Grant 5P50HL060296-04 from National Heart, Lung, And Blood Institute, IRG: ZHL1

Abstract: The loss of upper airway muscle tone in sleep is the precipitating cause of sleep apnea. Sleep apnea affects 3-5% of men over 40 and 1.5-2.5% of post-menopausal women. It causes persistent sleepiness, exacerbates a variety of medical conditions and increases morbidity and mortality. We will study how forebrain sleep induction mechanisms cause the reduction of muscle tone in airway dilators. A variety of complementary techniques will be used in sleep apnea patients to determine which forebrain and brainstem regions are activated and inactivated during airway obstruction. In projects 2 and 3 the pathways from forebrain sleep inducing regions will be traced to the brainstem region activated and inactivated in sleep apnea, focusing on regions controlling upper airway muscle tone. These studies will use anatomical tract tracing techniques, thermal activation of sleep controlling neurons and unit recording in the posterior hypothalamus, periaqueductal gray and medulla of unrestrained animals. In projects 4 and 5 we will determine which amino acid and monoamine transmitters mediate the suppression of muscle tone in airway dilator motoneurons during REM and non-REM sleep. These studies will use in vivo microdialysis, intracellular unit recording and iontophoresis. This program will bring basic science techniques to bear on the important clinical problem of sleep apnea. Pilot studies for this collaborative enterprise have already yield data that will produce a major revision in our understanding of the mechanisms controlling the airway during sleep. The work of this SCOR (Specialized Center of Research) will increase our understanding of sleep apnea. It is also likely to be of importance to other disorders of motor control during sleep. It is also likely to be of importance to other disorders of motor control during sleep, including REM sleep behavior disorder, bruxism, periodic limb movements during sleep and cataplexy. This research will also shed light on the cellular mechanisms controlling REM and non-REM sleep states

Keywords: sleep, sleep apnea

Project start date: 1998-09-01

Project end date: 2003-08-31

5P50HL060296-04 (2001): $1463214

5P50HL060296-03 (2000): $1415279

CNS Interactions With Hypoxia In OSA

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5P50HL060296-10 from National Heart, Lung, And Blood Institute, IRG: ZHL1

Abstract: The etiology of OSA remains unclear. Although small airway size is clearly a contributor, it is poorly correlated with symptomatology. Treatment of OSA with CPAP and related airway dilation strategies can normalize respiration during sleep, but successful treatment of the airway obstruction in OSA commonly leaves the patient with continued sleepiness and impaired cognitive function. The theme of this SCOR is that both the etiology and consequences of OSA are linked to neurological damage. Our goal is to determine the nature and cause of this damage and begin to develop treatment strategies. Harper has recently presented the first evidence for gray matter loss in OSA patients in cerebellar, limbic and cortical areas that mediate respiratory and blood pressure control, suggesting that this damage may be causal to apnea, whereas other regions show damage that is likely to be a result of OSA. He will use high resolution volumetric structural MRI and diffusion tensor MRI to define this damage and functional MRI to evaluate the dynamics of activity in these regions in OSA patients in response to autonomic challenge. Gozal will test the hypothesis that chronic intermittent hypoxia (CIH) mediated damage results from an inappropriate downregulation of the expression of monocarboxylate transporter 2. He will test this hypothesis using biochemical and transgenic approaches. Siegel will test the hypothesis that CIH interacts with the sleep disruption resulting from OSA to produce oxidative stress. He will explore the role of glutamate and serotonin mediated excitotoxicity and will test strategies for preventing this damage. Chase will study the interaction of sleep state and hypoxia using intracellular recording and iontophoresis to compare CA1 and CA3 responses, investigate the role of glutamate, hypocretin and nitric oxide production in these responses and describe the anatomical consequences of these changes. McGinty will test the hypothesis that CIH and sleep disruption effects on cognitive function in OSA are mediated by disruption of neurogenesis. He will examine the role of brain temperature and serotonin in this effect. Szymusiak will test the hypothesis that CIH causes persistent sleepiness in treated OSA patients due to dysregulation among sleep-and arousal regulatory systems in the preoptic area and posterior hypothalamus. He will use fos protein immunoreactivity and double labeling for neurotransmitter markers to identify affected neurons responsible for increased sleepiness.

Keywords: hypoxia, respiratory airflow disorder, sleep apnea, clinical research

Project start date: 1998-09-01

Project end date: 2008-08-31

5P50HL060296-10 (2007): $1525863

5P50HL060296-09 (2006): $1532312

5P50HL060296-08 (2005): $1530283

5P50HL060296-07 (2004): $1763232

RETICULAR FORMATION NEURONS: BEHAVIORAL STUDIES

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01NS014610-06 from National Institute Of Neurological Disorders And Stroke, IRG: BPO

Abstract: We propose to systematically study the movement relations of cells throughout the RF in unrestrained cats 1) Visual and polygraphic observations will be employed to determine the movement relations of RF units during spontaneous behaviors and during systematic behavioral manipulation. Units will be monitored during sleep-waking cycles to determine if any group of RF cells discharges selectively in REM sleep and could therefore have an "executive" role in its control. 2) Photographic techniques will be used to describe the temporal relationship between unit discharge and movement, and determine the precise topography of movements related to unit activity. 3) Recording of EMG activity will be used to determine if the different classes of RF units are related to activity in recorded muscles and to investigate the pattern of unit-muscle relationships. These studies will lead to a better understanding of the functional roles of RF units. Systematic study and mapping of this brainstem motor control system should contribute to comprehension of its role in both normal behavior and in motor system pathology.

Keywords: BIO-PSYCHOLOGY STUDY SECTION, BRAIN, RETICULAR FORMATION, PSYCHOBIOLOGY, PSYCHOPHYSIOLOGY, psychomotor function, PSYCHIC ACTIVITY LEVEL, SLEEP, REM, PSYCHOLOGY, NEUROPSYCHOLOGY (GENERAL), SENSORY-PERCEPTUAL PROCESSES, PROPRIOCEPTION, CELLS, SINGLE CELL ANALYSIS, MAMMALS, CARNIVORES, CATS

Project start date: 1983-02-01

Project end date: 1987-01-31

RETICULAR FORMATION NEURONS: RELATION TO MOTOR ACTIVITY

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01NS014610-03 from National Institute Of Neurological Disorders And Stroke, IRG: EXP

Abstract: We propose to systematically study the movement relations of cells throughout the RF in unrestrained cats 1) Visual and polygraphic observations will be employed to determine the movement relations of RF units during spontaneous behaviors and during systematic behavioral manipulation. Units will be monitored during sleep-waking cycles to determine if any group of RF cells discharges selectively in REM sleep and could therefore have an "executive" role in its control. 2) Photographic techniques will be used to describe the temporal relationship between unit discharge and movement, and determine the precise topography of movements related to unit activity. 3) Recording of EMG activity will be used to determine if the different classes of RF units are related to activity in recorded muscles and to investigate the pattern of unit-muscle relationships. These studies will lead to a better understanding of the functional roles of RF units. Systematic study and mapping of this brainstem motor control system should contribute to comprehension of its role in both normal behavior and in motor system pathology.

Keywords: BIO-PSYCHOLOGY STUDY SECTION, BRAIN, RETICULAR FORMATION, psychomotor function, NEUROPSYCHOLOGY (GENERAL), PSYCHIC ACTIVITY LEVEL, SLEEP, REM, SENSORY-PERCEPTUAL PROCESSES, PROPRIOCEPTION, CELLS, SINGLE CELL ANALYSIS, MAMMALS, CARNIVORES, CATS

Project start date: 1978-09-15

Project end date: 1982-07-31

Sleep In Cetaceans

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01NS042947-04 from National Institute Of Neurological Disorders And Stroke, IRG: ZRG1

Abstract: The sleep of cetaceans (the dolphins and toothed whales) has unique properties that may provide important insights into the evolution and function of sleep. Cetacean sleep may also allow us to differentiate between the behavioral roles of the several neurotransmitter systems that have been implicated in sleep and arousal. One of the unusual properties of cetacean sleep is the presence of long periods of "unihemispheric slow wave sleep" (USWS). A number of species of cetacean have been examined and all have only USWS, i.e. both hemispheres never show high voltage activity at the same time. Another unusual feature of cetacean sleep is the apparent absence or perhaps the near absence of REM sleep. If cetaceans do not have REM sleep, they would be the only mammals lacking this state. In the proposed studies, we will determine the nature of the changes in sensory and motor function during USWS in the bottlenose dolphin and beluga whale. We will present lateralized and not lateralized stimuli of different modalities to dolphins and whales adapted to sleep in stretchers to determine if sensory thresholds are altered ipsilateral and contralateral to USWS. We will measure the release of serotonin, norepinephrine, acetylcholine, and hypocretin bilaterally with cortical microdialysis and determine whether all or any of these transmitters have asymmetrical release during USWS. We will use telemetry and digital recorders to search for evidence of REM sleep in freely swimming cetaceans, monitoring the EEG, EMG, EOG and autonomic signs of REM sleep, including muscle jerks, rapid eye movements, and erections. We will determine whether the "jerks" that have been observed are signs of REM sleep, arousal or myoclonus. We will search for REM sleep-like periods of reduced monoamine release in dolphins and whales sleeping in stretchers. We will investigate the neuroanatomy of the brainstem and forebrain aminergic, cholinergic and hypocretin cell groups involved in behavioral state control in cetaceans. The proposed studies take advantage of a rapidly vanishing opportunity to study cetacean sleep. They will improve our understanding of the physiological and neurochemical substrates of mammalian sleep.

Keywords: Cetacea, ethology, psychomotor function, sleep, REM sleep, brain electrical activity, brain interhemispheric activity, cerebral dominance, neurochemistry, neurotransmitter, neurotransmitter transport, orexin, sensory threshold, Commonwealth of Independent States, behavioral /social science research tag, brain mapping, electroencephalography, electromyography, microdialysis, telemetry

Project start date: 2003-09-01

Project end date: 2008-06-30

5R01NS042947-04 (2006): $259240

5R01NS042947-03 (2005): $265480

5R01NS042947-02 (2004): $265480

1R01NS042947-01A1 (2003): $295413

CONTROL OF AIRWAY MOTOR NEURONS DURING SLEEP/WAKEFULNESS

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 1P50HL060296-01 from National Heart, Lung, And Blood Institute, IRG: ZHL1

Abstract: The loss of upper airway muscle tone in sleep is the precipitating cause of sleep apnea. Sleep apnea affects 3-5% of men over 40 and 1.5-2.5% of post-menopausal women. It causes persistent sleepiness, exacerbates a variety of medical conditions and increases morbidity and mortality. We will study how forebrain sleep induction mechanisms cause the reduction of muscle tone in airway dilators. A variety of complementary techniques will be used in sleep apnea patients to determine which forebrain and brainstem regions are activated and inactivated during airway obstruction. In projects 2 and 3 the pathways from forebrain sleep inducing regions will be traced to the brainstem region activated and inactivated in sleep apnea, focusing on regions controlling upper airway muscle tone. These studies will use anatomical tract tracing techniques, thermal activation of sleep controlling neurons and unit recording in the posterior hypothalamus, periaqueductal gray and medulla of unrestrained animals. In projects 4 and 5 we will determine which amino acid and monoamine transmitters mediate the suppression of muscle tone in airway dilator motoneurons during REM and non-REM sleep. These studies will use in vivo microdialysis, intracellular unit recording and iontophoresis. This program will bring basic science techniques to bear on the important clinical problem of sleep apnea. Pilot studies for this collaborative enterprise have already yield data that will produce a major revision in our understanding of the mechanisms controlling the airway during sleep. The work of this SCOR (Specialized Center of Research) will increase our understanding of sleep apnea. It is also likely to be of importance to other disorders of motor control during sleep. It is also likely to be of importance to other disorders of motor control during sleep, including REM sleep behavior disorder, bruxism, periodic limb movements during sleep and cataplexy. This research will also shed light on the cellular mechanisms controlling REM and non-REM sleep states.

Keywords: sleep, sleep apnea

Project start date: 1998-09-01

Project end date: 2003-08-31

1P50HL060296-01 (1998): $1384545

CNS Interactions With Hypoxia In OSA

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 2P50HL060296-06 from National Heart, Lung, And Blood Institute, IRG: ZHL1

Abstract: The etiology of OSA remains unclear. Although small airway size is clearly a contributor, it is poorly correlated with symptomatology. Treatment of OSA with CPAP and related airway dilation strategies can normalize respiration during sleep, but successful treatment of the airway obstruction in OSA commonly leaves the patient with continued sleepiness and impaired cognitive function. The theme of this SCOR is that both the etiology and consequences of OSA are linked to neurological damage. Our goal is to determine the nature and cause of this damage and begin to develop treatment strategies. Harper has recently presented the first evidence for gray matter loss in OSA patients in cerebellar, limbic and cortical areas that mediate respiratory and blood pressure control, suggesting that this damage may be causal to apnea, whereas other regions show damage that is likely to be a result of OSA. He will use high resolution volumetric structural MRI and diffusion tensor MRI to define this damage and functional MRI to evaluate the dynamics of activity in these regions in OSA patients in response to autonomic challenge. Gozal will test the hypothesis that chronic intermittent hypoxia (CIH) mediated damage results from an inappropriate downregulation of the expression of monocarboxylate transporter 2. He will test this hypothesis using biochemical and transgenic approaches. Siegel will test the hypothesis that CIH interacts with the sleep disruption resulting from OSA to produce oxidative stress. He will explore the role of glutamate and serotonin mediated excitotoxicity and will test strategies for preventing this damage. Chase will study the interaction of sleep state and hypoxia using intracellular recording and iontophoresis to compare CA1 and CA3 responses, investigate the role of glutamate, hypocretin and nitric oxide production in these responses and describe the anatomical consequences of these changes. McGinty will test the hypothesis that CIH and sleep disruption effects on cognitive function in OSA are mediated by disruption of neurogenesis. He will examine the role of brain temperature and serotonin in this effect. Szymusiak will test the hypothesis that CIH causes persistent sleepiness in treated OSA patients due to dysregulation among sleep-and arousal regulatory systems in the preoptic area and posterior hypothalamus. He will use fos protein immunoreactivity and double labeling for neurotransmitter markers to identify affected neurons responsible for increased sleepiness.

Keywords: hypoxia, respiratory airflow disorder, sleep apnea, clinical research

Project start date: 1998-09-01

Project end date: 2008-08-31

2P50HL060296-06 (2003): $1779285

Behavioral Role Of Hypocretin

Jerome M Siegel, Professor
University Of California Los Angeles
office Of Research Administration
los Angeles, Ca 90095

Grant 5R01MH064109-06 from National Institute Of Mental Health, IRG: BRS

Abstract: The discovery of hypocretin (Hcrt)/orexin in 1998 and its link to human narcolepsy in 2001 has led to the publication of more than 1,100 studies of its anatomical distribution, physiology and role in pathology. Conspicuously absent in these publications were any studies of Hcrt cell (unit) firing, or Hcrt release, in relation to behavior. Such studies are an essential step in gaining an understanding of the functioning of this system. During the last cycle of this grant we have solved the problem of how to identify Hcrt units in the freely moving animal. We have also developed highly sensitive RIA techniques that allowed, for the first time, measurement of Hcrt release over individual sleep and waking states. We propose to use these findings and techniques to address key issues concerning the function of Hcrt neurons. We will determine the effects of food deprivation, eating, and glucose and insulin administration on Hcrt unit activity in freely behaving rats to test the hypothesis that these neurons are "orexigenic." We will investigate our hypothesis that Hcrt cell discharge in rodents is primarily related to motivated motor activity in a series of studies. We will use operant reinforcement in rats to produce high or low firing rates in Hcrt units to provide a novel and objective assessment of the behavioral correlates of their activity. We will use classical and operant conditioning to test our hypothesis that their activity is increased during reward anticipation and decreased during anxiety. We will test our hypothesis that animals without Hcrt are impaired in their ability to work for reward, but are not impaired in avoidance tasks. We will identify the neurotransmitters responsible for the changes in Hcrt unit activity across the sleep-waking cycle with reverse microdialysis. Unit recording studies and the well established species-specific nature of cataplexy indicate that the behavioral correlates of Hcrt cell activity may vary substantially across species. Accordingly, we will take advantage of a unique opportunity to directly measure Hcrt release in human subjects. We will measure Hcrt release in these subjects during a range of emotions and behaviors by microdialysis studies of temporal and frontal lobe regions. The proposed studies should clarify the nature of neurotransmitter control of Hcrt neurons, their involvement in narcolepsy and depression, and their normal physiological and behavioral roles in rodents and humans

Keywords: neuron, neurophysiology, neuropsychology, neuroregulation, orexin auditory stimulus, dietary restriction, eating, frontal lobe /cortex, glucose, insulin, narcolepsy, neuropeptide Y, operant conditioning, psychological reinforcement, temporal lobe /cortex, visual stimulus clinical research, electrocardiography, electroencephalography, genetically modified animal, high performance liquid chromatography, human subject, laboratory mouse, laboratory rat, microdialysis, single cell analysis

Project start date: 2001-08-01

Project end date: 2012-02-28

EVIDENCE FOR NEURONAL DEGENERATION IN CANINE NARCOLEPSY

Jerome M Siegel, Professor
Stanford University Stanford, Ca 94305

Grant 5P50NS023724-130005 from National Institute Of Neurological Disorders And Stroke, IRG:

Abstract: The anatomical changes responsible for narcolepsy remain unknown. While receptor abnormalities have been identified, it is unclear if these are the sole or major cause of the disease. The hypothesis to be tested in this project, is that narcolepsy is due to a localizable degenerative neuropathology that occurs prior to, or at the time of symptom onset. Using age and breed matched narcoleptic and control dogs, we will l. Quantify the changes in the volume of a number of brainstem and forebrain nuclei to identify regional degeneration in narcolepsy. 2. Look for the expression of immediate early genes (IEG S) (c-jun,jun-D and c-fos) prior to the onset of narcoleptic symptoms. Certain IEG s (c- jun and jun-D) have been shown to be expressed for prolonged periods during neuronal degeneration. 3. Use cupric silver staining technique to locate axonal degeneration. We will also use complementary histological stains (Hematoxylin-eosin and glial fibrillary acidic protein [GFAP]) to determine the nature of any localized or diffuse degeneration in narcolepsy. In pilot studies for this proposal using silver staining, we have found consistent and massive degeneration in certain limbic nuclei. specific to the narcoleptic dog. This finding encourages us to believe that we will be able to identify a localized neuropathology underlying this disease. However, even if the proposed volume, IEG and axonal degeneration studies are negative, these studies will be important in eliminating several major hypotheses of the etiology of narcolepsy.

Keywords: narcolepsy, neural degeneration, neurophysiology, axon, brain stem, disease model, oncogene, prosencephalon, dog, histopathology, immunocytochemistry

Project start date: 1999-06-01

Project end date: 2000-08-31

COMPARATIVE PHYSIOLOGY OF SLEEP

Jerome M Siegel, Professor
University Of California Los Angeles
office Of Research Administration
los Angeles, Ca 90095

Grant 1R01NS032819-01 from National Institute Of Neurological Disorders And Stroke, IRG: BPO

Abstract: Since its discovery in 1953, REM sleep has been found to be almost universal among mammalian species. It is present in primates, ungulates, seals, carnivores, marsupials, insectivores, bats, rodents, cetaceans and other orders. The only animal with a well documented absence of REM sleep is the short-beaked echidna (Tachyglossus aculeatus). The short beaked echidna is one of only 3 existing species of monotreme. The other two monotreme species are the closely related long beaked echidna (Zaglossus bruijni) and the ancient duck billed platypus (Ornithorhynchus anatinus). Monotremes diverged from the line that led to placental and marsupial mammals 130 million years ago. The living monotremes have been shown to retain many characteristics of species ancestral to modern mammalian orders. They offer a unique opportunity to make inferences about the evolution of sleep. There has only been one study of echidna sleep, Allison et al.´s pioneering 1972 investigation. There have been no investigations of sleep in the platypus. We propose to determine whether the platypus has REM sleep. We will determine if the reported absence of REM sleep in the echidna is accompanied by a normal appearance of nonREM sleep activity patterns in brainstem neurons. We will monitor brainstem unit activity in the echidna to determine if any aspects of REM sleep are present in the cell groups known to change activity during this state. We will determine if locus coeruleus and raphe cells are silent during sleep or waking. We will determine if pontine units fire in a bursting pattern during sleep. We will map the distribution of cholinergic and aminergic cell groups in the brainstem of the echidna and platypus to determine how they differ from non-monotreme mammals. The Preliminary Data section demonstrates that we have overcome the technical and availability problems that have prevented the study of monotreme sleep. The function and origin of REM sleep remain the central questions of sleep research. REM sleep processes are likely to be involved in narcolepsy, the sudden infant death syndrome, depression, REM behavior disorder and other diseases. An understanding of how this state evolved would be of central importance to any comprehensive understanding of normal and pathological sleep state organization

Keywords: REM sleep, brain electrical activity, brain mapping, brain regulatory center, evolution Mammalia, acetylcholine, catecholamine, diurnal rhythm, dorsal raphe nucleus, locus coeruleus, species single cell analysis

Project start date: 1994-08-01

Project end date: 1997-07-31

1R01NS032819-01 (1994): $134518

CONTROL OF MUSCLE TONE BY THE NUCLEUS MAGNOCELLULARIS

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R37HL041370-10 from National Heart, Lung, And Blood Institute, IRG: BNR

Abstract: REM sleep is characterized by "paradoxical" changes in motor function. CNS structures that depolarize motoneurons show activity levels exceeding those of active waking, while simultaneous motoneuron hyperpolarization blocks motor output. Pathological activity in the systems responsible for motor inhibition and motor activation in REM sleep is believed to cause cataplexy, the sudden loss of muscle tone experienced by narcoleptics and the REM sleep behavior disorder. The loss of tone in accessory respiratory muscles during REM sleep causes the most severe oxygen desaturations of sleep apnea. The mechanisms responsible for these motor changes are poorly understood. We have found that electrical stimulation of the nucleus magnocellularis (NMC) of the medial medulla with a single pulse train causes a complete suppression of muscle tone. Repetitive stimulation produces locomotor movements. We demonstrated that the muscle tone suppression from NMC is triggered by non-NMDA glutamate receptors while the locomotion is triggered by NMDA receptors. The activation of both NMDA and non-NMDA receptors in NMC by glutamate release can explain the combination of atonia and motor activation that characterizes REM sleep. We found that lesions of NMC block the atonia of REM sleep. In studies of the narcoleptic dog, we found that a subpopulation of NMC neurons is active only during cataplexy and REM sleep. The goal of the present study is to analyze the NMC motor system. We hypothesize that locomotion and atonia are mediated by two distinct groups of glutamate sensitive neurons within NMC. We will test this hypothesis by extracellular unit recording and spike triggered averaging of muscle activity. We will characterize the inputs, morphology and transmitter of NMC atonia active cells using intracellular recording, intracellular staining and iontophoresis. We will map and contrast the properties of cell populations active during atonia with those active during locomotion, using c-fos immunohistochemistry. We will determine the distribution of non-NMDA receptors on each cell type, using an antibody to the AMPA receptor. This work will lead to a better understanding of the mechanism producing muscle atonia and motor activation in REM sleep. It will clarify the means by which this mechanism might be disturbed in narcolepsy, the REM behavior disorder, sleep apnea and other disorders of muscle tone control.

Keywords: REM sleep, medulla oblongata, muscle tone, narcolepsy, sleep apnea, NMDA receptor, action potential, brain electronic stimulator, brain mapping, motor neuron, neural conduction, neuroanatomy, single cell analysis, cat, fluorescence microscopy, immunocytochemistry, microelectrode

Project start date: 1988-08-01

Project end date: 1999-02-28

5R37HL041370-10 (1998): $170705

5R37HL041370-09 (1997): $164140

5R37HL041370-07 (1995): $151757

2R01HL041370-06A1 (1994): $142373

Hypocretin Release In Disease States And Behavior

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01MH064109-04 from National Institute Of Mental Health, IRG: ZRG1

Abstract: Recent work in our laboratory has indicated that a degenerative loss of hypocretin (orexin) neurons underlies most cases of human narcolepsy. Several chronic diseases have symptomatic similarities to narcolepsy. This suggests that they may share abnormalities in the operation of the hypocretin (Hcrt) system. For example, patients with unipolar depression and schizophrenia exhibit REM sleep at sleep onset, one of the defining characteristics of narcolepsy. Nighttime sleep is frequently disrupted in both disorders, as in narcolepsy. The age of onset of both of these disorders is similar to that of narcolepsy. Many patients with schizophrenia have hallucinations resembling the hypnagogic hallucinations of narcolepsy. Alzheimer s disease, like narcolepsy, is characterized by daytime sleepiness and nighttime sleep disruption. This "sundowning" and related hallucinatory mentation is the most frequent cause of institutionalization. We have developed a far more sensitive assay for Hcrt than that used in prior published studies and have access to a large number of cerebrospinal fluid (CSF) samples from these three groups of patients and suitable controls. We will determine if low Hcrt levels are unique to narcolepsy or if they are present in one or more of these other disorders. We will determine if an Hcrt blood test can be developed to detect narcolepsy. Such a test would have an enormous impact upon the diagnosis and treatment of sleep disorders and on sleep research in general. We will compare blood Hcrt levels in narcoleptics, sleep apneics, REM sleep behavior disorder patients and controls. In parallel animal studies, we will determine the effect of behavior, including motor activity, feeding and short term sleep deprivation upon CSF Hcrt levels. Finally, we will use in vivo microdialysis to determine the pattern of Hcrt release in locus coeruleus, hypothalamus and ventrolateral preoptic area across the sleep wake cycle. We will contrast release patterns in active vs. quiet waking and REM vs. nonREM sleep. These studies will help define the role of this newly identified neurotransmitter system in relation to motor behavior, the sleep wake cycle and in human disease.

Keywords: diagnosis design /evaluation, narcolepsy, neurotransmitter, Alzheimer s disease, REM sleep, behavior disorder, clinical depression, hallucination, hypothalamus, locus coeruleus, neural degeneration, neurotransmitter metabolism, preoptic area, psychomotor function, schizophrenia, sleep deprivation, sleep disorder, blood test, cat, cerebrospinal fluid, dog, human tissue, microdialysis

Project start date: 2001-08-01

Project end date: 2005-07-31

5R01MH064109-04 (2004): $305000

5R01MH064109-03 (2003): $305000

5R01MH064109-02 (2002): $305000

1R01MH064109-01 (2001): $305916

Intermittent Hypoxia And Oxidative Stress

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 2P50HL060296-060008 from National Heart, Lung, And Blood Institute, IRG: ZHL1

Abstract: Recent findings by Harper s group indicate that obstructive sleep apnea (OSA) is accompanied by brain damage in humans. It has been shown by Gozal s group that subjecting rats to levels of intermittent hypoxia similar to those seen in human OSA for 12h/day causes marked increases in apoptosis in CA1 hippocampus and neocortex, but not in CA3. Reduced expression of the NMDA NR1 glutamate receptor is also seen in CAl. These rats show long lasting cognitive deficits after their return to normoxic conditions. These deficits may be analogous to the persisting deficits commonly seen in human OSA patients after the apparently successful reversal of their sleep apnea. In prior studies, our group has shown that sleep deprivation under normoxic conditions leads to altered enzymatic activity in certain brain regions, consistent with the occurrence of oxidative stress. In the proposed studies we will test the hypothesis that chronic intermittent hypoxia (CIH) leads to changes in the activities of antioxidative enzymes and in the levels of free radical generated products and that these effects interact with the sleep disruption in OSA to produce cell damage. We will determine the time course and regional distribution of oxidative stress indicators under CIH. We have preliminary evidence showing increased activities of antioxidative enzymes under CIH. One of the principal means by which oxidative stress damages neurons is by excitotoxicity mediated by glutamate (and serotonin) release. We will use in vivo microdialysis to monitor the release of these neurotransmitters under CIH conditions and determine the time course of release with respect to sleep states. We hypothesize that CIH produces a larger increase in glutamate and serotonin release in waking than in nonREM sleep relative to normoxic conditions and that a portion of the damage in OSA is a result of this CIH interaction with periodic arousal. We will compare oxidative stress measures and neurotransmitter release in CA1 and CA3 to determine whether the relative resistance of CA3 to CIH is due to lower levels of oxidative stress or whether it results from a greater resistance of these neurons to comparable metabolic insult. We will determine if antioxidants and NMDA receptor blockers can protect against the detrimental effects of CIH under conditions of sleep disruption. These studies will clarify the dynamics underlying CIH induced brain damage and may facilitate the development of physiological and pharmacological approaches to minimize such damage in OSA.

Keywords: NMDA receptor, antioxidant, glutamate, hypoxia, oxidative stress, serotonin, sleep apnea, brain injury, free radical, neurotoxicology, superoxide dismutase, electroencephalography, electromyography, high performance liquid chromatography, histochemistry /cytochemistry, laboratory rat, western blotting

Project start date: 2003-09-01

Project end date: 2008-08-31

TRANSMITTER RELEASE ONTO AIRWAY MOTONEURONS DURING SLEEP

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 1P50HL060296-010004 from National Heart, Lung, And Blood Institute, IRG:

Abstract: Obstructive sleep apnea results from the interaction of an inadequate airway with the loss of tone in airway dilators. We hypothesize that the loss of tone during sleep is due to both 1. Active inhibition of airway dilator motoneurons by glycine and GABA and 2. Disfacilitation of airway dilator motoneurons by the withdrawal of noradrenergic, serotonergic and glutamatergic inputs. We further hypothesize that this combination of inhibition and disfacilitation is present if trigeminal, hypoglossal and ambiguus motoneurons. We hypothesize that glutamate release onto trigeminal, hypoglossal and ambiguus motoneurons is selectively decreased in NREM sleep, whereas norepinephrine and serotonin released are minimal in REM sleep. We propose to test these hypothesis by conducting the first microdialysis studies of amino acid and norepinephrine release into motoneurons as a function of sleep state. We will also measure serotonin release in all these sites across the sleep cycle. We will study the release of these transmitters in the decerebrate animal and during naturally occurring sleep. We will determine if the profile of transmitter release across the sleep cycle differs in trigeminal, hypoglossal and ambiguus motoneurons. We will determine the effect of activating hypnogenic neurons in the preoptic area by local warming and the effect of inactivating periaqueductal gray neurons, on transmitter release onto upper airway dilator motoneurons. Our pilot data have already provided important new insights into how airway muscle tone is controlled and demonstrate the feasibility of our approach. This work will allow us to identify the major amino acid and monoamine neurotransmitters involved in the loss of tone in airway dilators during REM and NREM sleep. It will also have implications for understanding brain mechanisms controlling muscle tone in normal and pathological conditions.

Keywords: motor neuron, muscle tone, nasopharynx, neuroregulation, neurotransmitter, neurotransmitter transport, respiratory muscle, sleep, REM sleep, gamma aminobutyrate, glycine, norepinephrine, periaqueductal gray matter, preoptic area, serotonin, sleep apnea, cat, decerebration, microdialysis

FOREBRAIN PATHOLOGY IN NARCOLEPSY

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01NS014610-19 from National Institute Of Neurological Disorders And Stroke, IRG: BPO

Abstract: Narcolepsy is a disease characterized by daytime sleepiness, hypnagogic hallucinations, sleep paralysis and cataplexy. In humans, the symptoms begin to appear at adolescence and continue throughout adulthood, limiting employment and education, and leading to accidents. It has been hypothesized that narcolepsy is a disease of REM sleep regulation and that its principal symptoms represent an "escape" of REM sleep components into waking. For example, cataplexy and sleep paralysis are hypothesized to represent a triggering of the REM sleep muscle tone suppression mechanism in waking. Drugs that manipulate the cholinergic and noradrenergic systems strongly affect the primary symptoms of narcolepsy, although the side effects of such drugs greatly limit their therapeutic utility. We propose to investigate the changes in neuronal activity underlying cataplexy. We will employ microwire techniques to record from the pedunculopontine (PPN), laterodorsal tegmental (LDT) and locus coeruleus nuclei during cataplectic attacks. These are the principal pontine nuclei implicated in REM sleep control. We will determine the direction and time course of changes in discharge in these cell groups in relation to cataplexy and REM sleep. We will determine how doses of drugs that affect cataplexy alter the activity of each cell type. A better understanding of the circuit underlying cataplexy and the way in which drugs affect the neurons in this circuit would aid in the development of more specific treatments for narcolepsy. It would also shed light on the mechanisms generating REM sleep, controlling muscle tone and regulating arousal.

Keywords: REM sleep, brain electrical activity, histopathology, narcolepsy, neural degeneration, prosencephalon, amygdala, brain septal area, cell death, neural information processing, neuropharmacology, dog, electrophysiology, human tissue, postmortem, single cell analysis

Project start date: 1983-02-01

Project end date: 1999-03-31

5R01NS014610-19 (1998): $159929

5R01NS014610-18 (1997): $153778

PONTINE UNIT ACTIVITY IN NARCOLEPCY

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01NS014610-16 from National Institute Of Neurological Disorders And Stroke, IRG: BPO

Abstract: Narcolepsy is a disease characterized by daytime sleepiness, hypnagogic hallucinations, sleep paralysis and cataplexy. In humans, the symptoms begin to appear at adolescence and continue throughout adulthood, limiting employment and education, and leading to accidents. It has been hypothesized that narcolepsy is a disease of REM sleep regulation and that its principal symptoms represent an "escape" of REM sleep components into waking. For example, cataplexy and sleep paralysis are hypothesized to represent a triggering of the REM sleep muscle tone suppression mechanism in waking. Drugs that manipulate the cholinergic and noradrenergic systems strongly affect the primary symptoms of narcolepsy, although the side effects of such drugs greatly limit their therapeutic utility. We propose to investigate the changes in neuronal activity underlying cataplexy. We will employ microwire techniques to record from the pedunculopontine (PPN), laterodorsal tegmental (LDT) and locus coeruleus nuclei during cataplectic attacks. These are the principal pontine nuclei implicated in REM sleep control. We will determine the direction and time course of changes in discharge in these cell groups in relation to cataplexy and REM sleep. We will determine how doses of drugs that affect cataplexy alter the activity of each cell type. A better understanding of the circuit underlying cataplexy and the way in which drugs affect the neurons in this circuit would aid in the development of more specific treatments for narcolepsy. It would also shed light on the mechanisms generating REM sleep, controlling muscle tone and regulating arousal.

Keywords: REM sleep, brain electrical activity, narcolepsy, pons, alpha antiadrenergic agent, cataplexy, neural information processing, neuropsychology, physostigmine, prazosin, scopolamine, yohimbine, dog, electrophysiology, single cell analysis

Project start date: 1983-02-01

Project end date: 1996-03-31

5R01NS014610-16 (1995): $164778

5R01NS014610-15 (1994): $158440

5R01NS014610-14 (1993): $156700

RETICULAR FORMATION NEURONS: BEHAVIORAL STUDIES

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01NS014610-09 from National Institute Of Neurological Disorders And Stroke, IRG: BPO

Abstract: Despite recent evidence of anatomical specificity, behavioral studies have generally concluded that cells in the medial ponto-medullary reticular formation (RF) have relatively nonspecific roles in either attention, sleep, motivation, regulation of muscle tone or in other activities. Using techniques that this laboratory has developed for behavioral analysis and unit recording in freely moving animals, a number of RF cell types have been discovered. Each cell type has a specific motor correlate and a unique pattern of sensory and reflex response, sleep cycle discharge and anatomical distribution. On the basis of these studies and recent anatomical and neurophysiological data, we have hypothesized that most RF cells generate specific patterns of muscle contraction in the axial musculature. We propose to use spike triggered averaging to analyze the contribution of RF head movement cells to excitation and inhibition in neck flexors. We will determine whether the activity of these cells precedes or follows activity in the contracting muscles. Using antidromic and orthodromic stimulation from spinal cord, motor cortex, tectum and vestibular nucleus, the differences in synaptic inputs and axonal outputs of behaviorally defined cell types will be determined. This analysis will allow us to link behavioral cell type identification with the large body of physiological and anatomical data identifying RF cells on the basis of monosynaptic inputs and axonal outputs. Recent reports finding no motor, postural, or other behavioral deficits after kainic acid lesions of the RF pose a major problem for the specific motor hypothesis of RF function, and other RF hypotheses. We propose to identify behavioral deficits after ibotenic acid lesions of the RF by the use of more sensitive measures of motor activity. Pilot studies for this experiment have provided the first evidence of motor deficits after axon sparing lesions of the RF. The relative contributions of cell bodies and axons to lesion effects will be assessed by using lidocaine injections to reversibly block fibers of passage. The acute behavioral effects of neuronal stimulation after injection of ibotenic acid will also be determined. These studies should permit the anatomical localization of behavioral functions within the RF and the identification of the cellular elements participating in these functions. Changes in normal RF operation are likely to contribute to a number of sleep and motor disorders.

Keywords: BRAIN, RHOMBENCEPHALON, RETICULAR FORMATION, INFORMATION PROCESSING AND CONTROL (NEURAL), NEUROMOTOR SYSTEM, NEUROMUSCULAR TRANSMISSION, SKELETAL MOVEMENT, HEAD MOVEMENT, psychobiology, BRAIN, MESENCEPHALON, BRAIN, MESENCEPHALON, COLLICULUS SUPERIOR, BRAIN, RHOMBENCEPHALON, PONS, VESTIBULAR NUCLEI, BRAIN, TELENCEPHALON, CEREBRUM, CORTEX, MOTOR CORTEX, MUSCLE FUNCTION, MUSCLE CONTRACTION, NERVOUS SYSTEM, NERVE ENDINGS, SYNAPSES, NERVOUS SYSTEM, NEURONS, AXONS, NEUROMOTOR SYSTEM, SENSORIMOTOR SYSTEMS, NEUROPHYSIOLOGY, NERVE IMPULSE INHIBITION, NEUROPHYSIOLOGY, NERVE IMPULSE INITIATION, NEUROPHYSIOLOGY, NERVE THRESHOLDS, NEUROPHYSIOLOGY, REFLEX, STARTLE REACTION, PSYCHOLOGY, NEUROPSYCHOLOGY, brain mapping, ANIMALS, CHORDATES, MAMMALS, CARNIVORES, CATS, BRAIN LESIONS SURGICAL, CEREBELLECTOMY, BRAIN LESIONS SURGICAL, DECEREBRATION, CELLS, SINGLE CELL ANALYSIS, ELECTROPOTENTIALS, SPIKE POTENTIAL, MUSCLE FUNCTION, ELECTROMYOGRAPHY, NERVOUS SYSTEM CENTRAL, SPINAL CORD MAPPING, NEUROTOXINS, PSYCHOLOGICAL TESTS, BEHAVIOR ASSESSMENT-MEASUREMENT

Project start date: 1983-02-01

Project end date: 1989-03-31

Behavioral Role Of Hypocretin

Jerome M Siegel, Professor
Noneuniversity Of California Los Angeles, Office Of Research Administration, Los Angeles, Ca 90024

Grant 2R01MH064109-05A1 from National Institute Of Mental Health, IRG: BRS

Abstract: DESCRIPTION () The discovery of hypocretin (Hcrt)/orexin in 1998 and its link to human narcolepsy in 2001 has led to the publication of more than 1,100 studies of its anatomical distribution, physiology and role in pathology. Conspicuously absent in these publications were any studies of Hcrt cell (unit) firing, or Hcrt release, in relation to behavior. Such studies are an essential step in gaining an understanding of the functioning of this system. During the last cycle of this grant we have solved the problem of how to identify Hcrt units in the freely moving animal. We have also developed highly sensitive RIA techniques that allowed, for the first time, measurement of Hcrt release over individual sleep and waking states. We propose to use these findings and techniques to address key issues concerning the function of Hcrt neurons. We will determine the effects of food deprivation, eating, and glucose and insulin administration on Hcrt unit activity in freely behaving rats to test the hypothesis that these neurons are "orexigenic." We will investigate our hypothesis that Hcrt cell discharge in rodents is primarily related to motivated motor activity in a series of studies. We will use operant reinforcement in rats to produce high or low firing rates in Hcrt units to provide a novel and objective assessment of the behavioral correlates of their activity. We will use classical and operant conditioning to test our hypothesis that their activity is increased during reward anticipation and decreased during anxiety. We will test our hypothesis that animals without Hcrt are impaired in their ability to work for reward, but are not impaired in avoidance tasks. We will identify the neurotransmitters responsible for the changes in Hcrt unit activity across the sleep-waking cycle with reverse microdialysis. Unit recording studies and the well established species-specific nature of cataplexy indicate that the behavioral correlates of Hcrt cell activity may vary substantially across species. Accordingly, we will take advantage of a unique opportunity to directly measure Hcrt release in human subjects. We will measure Hcrt release in these subjects during a range of emotions and behaviors by microdialysis studies of temporal and frontal lobe regions. The proposed studies should clarify the nature of neurotransmitter control of Hcrt neurons, their involvement in narcolepsy and depression, and their normal physiological and behavioral roles in rodents and humans.

Project start date: 2001-08-01

Project end date: 2012-02-28

2R01MH064109-05A1 (2007): $595968

CORE--Hypoxia And Histology

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 2P50HL060296-069002 from National Heart, Lung, And Blood Institute, IRG: ZHL1

Abstract: Core facilities will have specialized nitrogen and oxygen gas generation facilities to minimize costs that would otherwise be incurred in gas tank purchases for the high volume gas use required for intermittent and chronic hypoxia studies. The Core unit will also include computer controlled control equipment to regulate gas mixtures according to sensors in the chambers to allow the exposure of rats to conditions of chronic and intermittent hypoxia. These rats will be used in studies by Drs. Gozal, Siegel, McGinty and Szymusiak. Core facilities will also include histology facilities to be used for immunohistochemistry and other standard histology stains by Drs. Chase, Gozal, Siegel, McGinty and Szymusiak. Finally, the Core will contain an administrative unit to be used by all investigators to coordinate SCOR meetings and data and manuscript exchange, visits by invited faculty, and required reports.

Keywords: biomedical facility, histology, hypoxia, nitrogen, oxygen, immunocytochemistry, laboratory rat

Project start date: 2003-09-08

Project end date: 2008-08-31

IMMUNOLOGICAL FACTORS IN NARCOLEPSY

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R37NS014610-23 from National Institute Of Neurological Disorders And Stroke, IRG: ZRG1

Abstract: Applicant s ) Narcolepsy is characterized by overwhelming sleepiness, cataplexy, sleep paralysis and hypnagogic hallucinations. Genetic studies have identified a link between narcolepsy and HLA haplotype. Because the HLA region specifies the proteins used to present antigen and because most HLA linked diseases are autoimmune, it has been suggested that narcolepsy is an autoimmune disease. However, there is no convincing evidence for this hypothesis. During the current grant period we have found the first evidence for a neurodegenerative process in narcolepsy. Studying narcoleptic dogs, we saw that degeneration occurred over a relatively short time period and was localized to basal forebrain, amygdala and adjacent regions. These regions are known to have key roles in the control of sleep and in the regulation of brainstem motor tone control systems. The highly localized nature of the degeneration and the relatively short duration of the degenerative events may explain the failure to find evidence for active immune processes in fully symptomatic human or canine narcoleptics. We conducted a pilot study of the effects of immunosuppression on narcoleptic dogs during the period of degeneration, using glucocorticoids, azathioprine and methotrexate. We saw a delay of symptom onset and a marked reduction of symptom intensity in all treated animals. The change in symptom severity appears to be permanent. We also found evidence that immune activation exacerbates symptomatology. If verified in a larger group of animals, these would be the first manipulations shown to affect the course of the narcoleptic disease process, and would be important evidence for immune system involvement in the pathogenesis of narcolepsy. In further pilot work, we saw CD3+ T cells at the sites of degeneration in untreated narcoleptics, key evidence for immune involvement. We propose to study the effect of immunosuppression on the development of narcolepsy. We will determine whether we can completely prevent the development of symptoms with combined prednisone and methotrexate treatment. We will see whether there is a critical period for intervention. We will determine whether immune activation exacerbates symptomatology. We will look for evidence of lymphocytes and activated microglia at the sites where we have seen degeneration. This work could lead to a treatment for human narcolepsy and to a better understanding of the cause of this debilitating disease.

Keywords: artificial immunosuppression, disease /disorder etiology, methotrexate, narcolepsy, neural degeneration, prednisone, CD3 molecule, MHC class II antigen, amygdala, azathioprine, basal ganglia, cataplexy, chemoprevention, disease /disorder model, interferon gamma, leukocyte activation /transformation, macrophage activating factor, neuropathology, nonhuman therapy evaluation, behavior test, dog, histology

Project start date: 1983-02-01

Project end date: 2003-06-30

5R37NS014610-23 (2002): $358727

5R37NS014610-22 (2001): $348280

5R37NS014610-21 (2000): $338135

COMPARATIVE PHYSIOLOGY OF SLEEP

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 2R01NS032819-04 from National Institute Of Neurological Disorders And Stroke, IRG: BPO

Abstract: adapted from applicant s ) In the current grant period, these investigators have found that the platypus and echidna, primitive mammals previously thought to lack REM sleep, have REM sleep in very large amounts. This finding suggests that REM sleep may have evolved in the reptilian ancestors of mammals. Aminergic and cholinergic neurons have central roles in REM sleep control. Noradrenergic and serotonergic cells are tonically active during waking and reduce discharge rate in nonREM sleep. During REM sleep, and only during REM sleep, serotonergic and noradrenergic cell groups show a complete cessation of discharge in all mammals examined. A subpopulation of cholinergic cells is selectively active in REM sleep. Other cholinergic cells are active in both waking and REM sleep. Recent immunohistochemical work has established that these three cell groups exist in the reptile. These findings suggest that REM sleep or a precursor state should exist in reptiles. Observation of the discharge patterns of brainstem aminergic and cholinergic cell groups could determine the key neuronal characteristics of reptilian sleep. The investigators propose to conduct the first studies of brainstem monoaminergic and cholinergic cell discharge in non-mammalian species. They will use microwire techniques that allow long term recording in the freely moving animal. They will study the activity of noradrenergic, serotonergic and cholinergic cells during waking and sleep in two reptiles, the box turtle (Terrapene carolina) and the iguana (Iguana iguana). Study of the activity of aminergic and cholinergic cells in reptiles will provide critical data bearing on the evolution of 1) REM and nonREM sleep states; 2) the waking discharge patterns of aminergic and cholinergic cells; 3) the receptors and membrane mechanisms governing discharge of these cells in mammals; and 3) the functional role of these cell types.

Keywords: REM sleep, brain electrical activity, brain regulatory center, evolution, sleep, acetylcholine, brain mapping, brain stem, circadian rhythm, dorsal raphe nucleus, locus coeruleus, neurotransmitter receptor, norepinephrine, serotonin, species difference, wakefulness, Chelonia, Mammalia, electrocardiography, electroencephalography, immunocytochemistry, lizard, video recording system

Project start date: 1994-08-01

Project end date: 1999-11-30

2R01NS032819-04 (1998): $135310

NEURONAL DEGENERATION PRODUCED BY SLEEP DEPRIVATION

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01HL059594-04 from National Heart, Lung, And Blood Institute, IRG: ZHL1

Abstract: Adapted from  s description) Recent studies have provided the first convincing evidence for a syndrome of sleep deprivation induced physiological changes, distinct from sleepiness. These include elevation of metabolic rate, alterations in thermoregulation, increased food intake and other symptoms. Whereas most of these changes appear to be neurological in origin and they ultimately lead to death, no neuropathological correlates of this syndrome have been detected. In pilot studies for this proposal, these investigators have used the De Olmos amino-cupric sliver technique to look for degenerative changes in the brains of sleep deprived rats. They found axonal and somatic degeneration in the hypothalamus and basal forebrain after 10 days of sleep deprivation. If confirmed in a larger group of animals, this would be the first clear evidence that sleep deprivation produces neuronal degeneration. Phylogenetic and ontogenetic evidence demonstrate that the major correlate of sleep time is body size, with larger animals having as little as 10% of the sleep time of smaller animals. They hypothesize that larger animals incur less free radical damage to their central nervous systems due to a more favorable balance between oxidative stress and the activity of antioxidative enzymes. These applicants will test the hypothesis that free radical damage occurs during sleep deprivation by using a newly developed assay that allows the immunological detection of carbonyl radicals, and by labeling for 4-hydroxynonenal (HNE), an aldehyde product of lipid peroxidation; peroxynitrite a powerful oxidant; and heme oxygenase-1 (HO-1), an enzyme activated by oxidative stress. They will do these stains in conjunction with amino-cupric silver staining. They will attempt to reduce sleep deprivation induced damage by administration of the antioxidant PBN. They hypothesize that mammalian sleep enables elevated metabolic rate in waking, by providing an opportunity for repair of free radical damage in the central nervous system.

Keywords: brain metabolism, neural degeneration, oxidative stress, sleep deprivation, aldehyde, antioxidant, enzyme activity, heme oxygenase, lipid peroxide, neuropharmacology, peroxynitrite, histopathology, immunocytochemistry, laboratory rat, staining

Project start date: 1997-09-30

Project end date: 2002-08-31

5R01HL059594-04 (2000): $220500

5R01HL059594-03 (1999): $220500

5R01HL059594-02 (1998): $220500

1R01HL059594-01 (1997): $220500

Control Of Muscle Tone In NonREM Sleep

Jerome M Siegel, Professor
University Of California Los Angeles

Grant 5R01HL041370-18 from National Heart, Lung, And Blood Institute, IRG: BRS

Abstract: Abnormalities in muscle tone control across the sleep cycle lead to grave health problems. Sleep apnea causes hypertension, hypoxic necrosis, cognitive difficulties, heart failure and stroke. Sleepwalking often results in serious injury. Periodic limb movements during sleep (PLMS) can cause profound insomnia, particularly when linked to the restless leg syndrome (RLS). Nocturnal bruxism produces severe dental problems. Sleep apnea occurs in both nonREM and REM sleep. Sleepwalking, PLMS and nocturnal bruxism occur predominantly in nonREM sleep. Despite the link between these common disorders and nonREM sleep, most of our knowledge of motor control during sleep concerns the mechanisms underlying muscle tone suppression in REM sleep. The focus on REM sleep related aspects of motor disorders can be explained in part by the ease of triggering a REM sleep-like state in decerebrate or anesthetized animals by microinjection of carbachol or other substances. In contrast, nonREM sleep motor control mechanisms can only be investigated in intact, unanesthetized animals. We propose to determine the neurochemistry of muscle tone control in nonREM sleep using in vivo investigations in unrestrained, intact animals. We will also examine motor control in natural REM sleep. We will determine how monoamines, amino acids and acetylcholine are released onto motoneurons across the sleep cycle. We will take advantage of recent advances that we have made in the development of sensitive assays for GABA, hypocretin (Hcrt) and acetylcholine. We will also employ newly developed biosensors that have produced an order of magnitude increase in the temporal resolution of measurements of glutamate levels. We will infuse agonists, antagonists and reuptake blockers through dialysis membranes to determine the effects of these transmitters on muscle tone in nonREM sleep. Recent work has documented extensive neocortical and cerebellar damage in both human sleep apnea and animal models of sleep apnea. Initial damage in these areas appears to be a precipitating cause of sleep apnea in a large proportion of patients. Greater damage follows as a consequence of apnea. We will determine the effects of similar damage in rats on neurotransmitter release onto motoneurons in both nonREM and REM sleep. This will improve our understanding of this process, and lay the foundation for pharmacological intervention to interrupt the positive feedback loop that sustains and intensifies the sleep apnea syndrome. Our work will also suggest improved pharmacological treatments for PLMS, sleepwalking and bruxism

Keywords: cerebral ischemia /hypoxia, muscle tone, neurochemistry, neuromuscular function, neuropharmacology, neurotransmitter transport, sleep, sleep apnea aminoacid, biosensor device, bruxism, hypoglossal nerve, limb movement, motor neuron, neurotransmitter agonist, neurotransmitter antagonist, orexin, trigeminal nerve high performance liquid chromatography, laboratory rat, microdialysis

Project start date: 1988-08-01

Project end date: 2010-06-30

5R01HL041370-17 (2007): $305865

2R01HL041370-16A2 (2006): $307720

PONTINE UNIT ACTIVITY IN NARCOLEPTICS

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01NS014610-12 from National Institute Of Neurological Disorders And Stroke, IRG: BPO

Abstract: A large body of research has established that most aspects of the narcolepsy syndrome can best be understood as a disorder of REM sleep. Studies in cats have identified the neuronal Groups critical to REM sleep control. However, it is not known how these groups malfunction in the narcoleptic animal. We propose to conduct the first studies of the activity of pontine cells in the narcoleptic dog. Unit activity in "REM sleep-on", "REM sleep-off" and PGO (Ponto-geniculo-occipital) spike related cells will be examined during natural sleep and waking states in unrestrained narcoleptic dogs. We will determine the direction and time course of activity change in these cells during cataplexy and waking states. We will determine the response of these cells to treatments known to increase or decrease cataplexy. We will determine their projection pattern, conduction velocity and sensory responses. Not only will an analysis of pontine activity in the narcoleptic dog increase our understanding of narcolepsy, but it is also likely to provide fundamental insights into the mechanisms responsible for the regulation of REM sleep, muscle tone and arousal processes in the normal animal. We have extensive experience with all of the required techniques and have demonstrated their feasibility in studies in the medulla of the narcoleptic dog.

Keywords: REM sleep, narcolepsy, neurophysiology, pons, neural information processing, neuropsychology, sleep, wakefulness, dog, electrophysiology, single cell analysis, spike potential

Project start date: 1983-02-01

Project end date: 1992-03-31

IMMUNOLOGICAL FACTORS IN NARCOLEPSY

Jerome M Siegel, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R37NS014610-26 from National Institute Of Neurological Disorders And Stroke, IRG: NSS

Keywords: artificial immunosuppression, disease /disorder etiology, methotrexate, narcolepsy, neural degeneration, prednisone, CD3 molecule, MHC class II antigen, amygdala, azathioprine, basal ganglia, cataplexy, chemoprevention, disease /disorder model, interferon gamma, leukocyte activation /transformation, macrophage activating factor, neuropathology, nonhuman therapy evaluation, behavior test, dog, histology

Project start date: 1983-02-01

Project end date: 2007-06-30

5R37NS014610-26 (2005): $321216