| discharge modulation of rat dorsal raphe neurons during sleep and waking: effects of preoptic/basal forebrain warming. | in cats, putative serotonergic neurons (psns) recorded from the dorsal raphe nucleus (drn) across the sleep-wake cycle exhibit the so-called rapid eye movement sleep-off (rem-off) discharge pattern. since, the sleep-wake discharge patterns of drn neurons in behaving rats is poorly known, the present study examined this neuronal populations. the psns recorded in this study exhibited: (1) progressive decrease in discharge rate from waking to nrem to rem sleep; (2) long action potential duration, a ... | 2000 | 10967295 |
| sleep-wake effects following the selective 5-ht(1a) receptor antagonist p-mppi in the freely moving rat. | the 5-ht(1a) receptors appear to play an important role in the serotonergic modulation of sleep and waking. both presynaptic somatodendritic 5-ht(1a) autoreceptors and postsynaptic 5-ht(1a) heteroreceptors may be involved. the present study addressed the question of whether the selective 5-ht(1a) receptor antagonist 4-(2'-methoxy-phenyl)-1-[2'-(n-2"-pyridinyl)-p-iodobenzamido]-ethy l-p iperazine (p-mppi) affected sleep and waking and whether such an effect would be dose-related. polygraphic reco ... | 2000 | 10996044 |
| unrelated course of subthalamic nucleus and globus pallidus neuronal activities across vigilance states in the rat. | the pallido-subthalamic pathway powerfully controls the output of the basal ganglia circuitry and has been implicated in movement disorders observed in parkinson's disease (pd). to investigate the normal functioning of this pathway across the sleep-wake cycle, single-unit activities of subthalamic nucleus (stn) and globus pallidus (gp) neurons were examined, together with cortical electroencephalogram and nuchal muscular activity, in non-anaesthetized head-restrained rats. stn neurons shifted fr ... | 2000 | 10998119 |
| discharge patterns of neurons in cholinergic regions of the basal forebrain during waking and sleep. | a subset of neurons recorded in the magnocellular basal forebrain (mbf) of cats and rats exhibit elevated discharge rates during waking and rem sleep, and diminished discharge during sleep with cortical eeg synchrony (nonrem sleep). this pattern is observed in mbf neurons in cats with identified ascending projections, and in neurons located in cholinergic regions of the rat mbf. however, the cholinergic versus noncholinergic nature of recorded cells could not be determined with the extracellular ... | 2000 | 11000419 |
| the hypocretins: excitatory neuromodulatory peptides for multiple homeostatic systems, including sleep and feeding. | the hypocretins are two neuropeptides of related sequence that are produced from a common precursor whose expression is restricted to 1, 100 large neurons of the rat dorsal-lateral hypothalamus. the hypocretins have been detected immunohistochemically in secretory vesicles at synapses of fibers that project to areas within the posterior hypothalamus that are implicated in feeding behaviors and hormone secretion and diverse targets in other brain regions and in the spinal cord, including several ... | 2000 | 11020209 |
| adenosine as a biological signal mediating sleepiness following prolonged wakefulness. | recent reports from our laboratory have shown that extracellular adenosine levels selectively increase in basal forebrain during prolonged wakefulness in cats and rats. furthermore, microdialysis perfusion of adenosine into the basal forebrain (bf) increased sleepiness and decreased wakefulness in both the species, whereas perfusion of the a(1)-receptor-selective antagonist, cyclopentyl-1, 3-dimethylxanthine resulted in increased wakefulness, an observation similar to that found with caffeine or ... | 2000 | 11025338 |
| state dependent response of the locus caeruleus neurons to bladder distention. | the precise mechanism by which normal persons wake upon urinary sensation is unclear. the locus caeruleus in the pons is suggested to be involved in the activating systems for arousal. we evaluated the effects of bladder distention on the neural activity in the l. caeruleus under different states of anesthesia. | 2000 | 11025762 |
| activity of adenosine deaminase in the sleep regulatory areas of the rat cns. | there are data to support the notion that adenosine (ado), a neuromodulator in the cns, is an important regulator of sleep homeostasis. it has been demonstrated that ado agonists and antagonists strongly impact upon sleep. in addition, the level of adenosine varies across the sleep/wake cycle and increases following sleep deprivation. adenosine deaminase (ada) is a key enzyme involved in the metabolism of ado. we questioned, therefore, whether there are differences in adenosine deaminase activit ... | 2000 | 11038259 |
| neurotensin-induced bursting of cholinergic basal forebrain neurons promotes gamma and theta cortical activity together with waking and paradoxical sleep. | cholinergic basal forebrain neurons have long been thought to play an important role in cortical activation and behavioral state, yet the precise way in which they influence these processes has yet to be fully understood. here, we have examined the effects on the electroencephalogram (eeg) and sleep-wake state of basal forebrain administration of neurotensin (nt), a neuropeptide that has been shown in vitro to potently and selectively modulate the cholinergic cells. microinjection of (0.1-3.0 mm ... | 2000 | 11069953 |
| hypothalamic arousal regions are activated during modafinil-induced wakefulness. | modafinil is an increasingly popular wake-promoting drug used for the treatment of narcolepsy, but its precise mechanism of action is unknown. to determine potential pathways via which modafinil acts, we administered a range of doses of modafinil to rats, recorded sleep/wake activity, and studied the pattern of neuronal activation using fos immunohistochemistry. to contrast modafinil-induced wakefulness with spontaneous wakefulness, we administered modafinil at midnight, during the normal waking ... | 2000 | 11069971 |
| repeated 2-deoxy-d-glucose-induced glucoprivation attenuates fos expression and glucoregulatory responses during subsequent glucoprivation. | a condition of reduced responsiveness to hypoglycemia, known as hypoglycemia-associated autonomic failure (haaf), occurs in diabetic patients in the wake of a prior hypoglycemic episode. this condition suggests that hypoglycemia alters central glucose-sensing mechanisms. this experiment examined the effects of repeated 2-deoxy-d-glucose (2dg)-induced glucoprivation on subsequent 2dg-induced feeding and hyperglycemic responses in rats. fos immunoreactivity (ir) in adrenal medulla and brain sites ... | 2000 | 11078453 |
| effects of lateral preoptic area application of orexin-a on sleep-wakefulness. | deficiency of orexin, a newly discovered hypothalamic peptide, is thought to lead to abnormal sleepiness and cataplexy in both human narcolepsy and animal models of the disease. as the poa contains extensive orexin terminals and is established as a sleep/arousal regulatory site, we evaluated a hypothesis that this site is a target for the arousal-inducing effects of orexin. orexin-a was microinjected into lateral preoptic area (ipoa) and the effects on sleep-wakefulness and brain temperature wer ... | 2000 | 11095491 |
| muscarinic and pacap receptor interactions at pontine level in the rat: significance for rem sleep regulation. | cholinergic and pacapergic systems within the oral pontine reticular nucleus (pno) play a critical role in rem sleep generation in rats. in this present work, we have investigated whether rem sleep enhancement induced by carbachol (a cholinergic agonist) or pacap, depends on an interaction between muscarinic and pacap receptors. this hypothesis was tested by recording sleep-wake cycles in freely moving rats injected into the pno with pacap in combination with the muscarinic receptor antagonist a ... | 2000 | 11122360 |
| effects of bilateral microinjections of ibotenic acid in the thalamic reticular nucleus on delta oscillations and sleep in freely-moving rats. | the thalamic reticular nucleus (nrt) consists of a large pool of gabaergic neurons located on each side on the anterior, lateral, and ventral surfaces of the dorsal thalamus. the nrt is divided up into sectors. the aim of this study was to investigate the effects of bilateral lesions of the nrt on sleep and sleep oscillations. only the results concerning delta oscillations will be reported here. as a first step we produced stereotaxically placed electrolytic lesions. the rats presented continuou ... | 2000 | 11123522 |
| effect of electric foot shocks, immobilization, and corticosterone administration on the sleep-wake pattern in the rat. | knowledge concerning the impact of stressful situations on the sleep-wake pattern has been growing rapidly in the last decade. immobilization (imb) in rats elicits a significant increase of rapid eye movement (rem) sleep during the following 10 h. participation of the adrenergic system has been clearly shown in this effect. on the other hand, it is well known that the time of the circadian cycle in which the stressor is applied could influence the results. it is also well known that the activati ... | 2000 | 11134681 |
| the rat as an experimental model for sleep neurophysiology. | the aim of this study was to develop a sleep-wake recording system for rats that would yield results more comparable to those obtained from cats than those that are usually reported. for 18 male sprague-dawley rats, the authors combined measures of cortical and hippocampal electroencephalogram (eeg) and neck muscle electromyogram with the electrooculogram and pontine eeg, so that the behavioral states could be identified with greater confidence with the use of polygraphic criteria developed in t ... | 2000 | 11142656 |
| an automated system for recording and analysis of sleep in mice. | significant differences in many aspects of sleep/wake activity among inbred strains of mice suggest genetic influences on the control of sleep. a number of genetic techniques, including transgenesis, random and targeted mutagenesis, and analysis of quantitative trait loci may be used to identify genetic loci. to take full advantage of these genetic approaches in mice, a comprehensive and robust description of behavioral states has been developed. an existing automated sleep scoring algorithm, de ... | 2000 | 11145318 |
| rat sleep and eye movement density as biological markers of demyelinating disease. | myelin mutants provide an opportunity to study neurophysiological and behavioral effects of demyelination. the taiep rats are myelin mutants with progressive demyelination of the central nervous system (cns), resulting in five neurological symptoms: tremor, ataxia, immobility, epilepsy, and paralysis. the demyelination affects the brainstem, an important area in the control of sleep. this study compared eye movement density (emd) in taiep vs. normal control rats during paradoxical sleep (ps). it ... | 2000 | 11150558 |
| spike sequences and their consequences. | spatio-temporal patterns of spikes have an advantage of representing information by their spike composition similar to words of languages. first we review the models of neuronal coding, then we discuss technical aspects of detecting spatio-temporal spike patterns. we argue by presenting data from rat hippocampus that spike trains recorded simultaneously from multiple pyramidal cells are not independent. their hidden dependency structure can be revealed by spike 'sequences', defined as a set of n ... | 2000 | 11165916 |
| nociceptive responsiveness during slow-wave sleep and waking in the rat. | brainstem neurons that are thought to modulate pain are reported to have state-dependent discharge rates. yet, the effect of behavioral state upon nociceptive transmission has not been well studied. therefore, we examined responses to noxious thermal stimulation of the rat hindpaw presented during different behavioral states. noxious thermal stimuli were applied to rats as they spontaneously cycled through waking and sleeping states. two different methods of heating the paw - a focused light bul ... | 2001 | 11204051 |
| effects of centrally administered orexin-b and orexin-a: a role for orexin-1 receptors in orexin-b-induced hyperactivity. | orexin-a and orexin-b are hypothalamic neuropeptides derived from a 130-amino acid precursor, prepro-orexin, and are potent agonists at both the orexin-1 (ox1) and orexin-2 (ox2) receptors. orexin-a has been ascribed a number of in vivo functions in the rat after intracerebroventricular (icv) administration, including hyperphagia, neuroendocrine modulation and a role in the regulation of sleep-wake function. the in vivo role of orexin-b is not as clear. | 2001 | 11205421 |
| the suprachiasmatic nucleus projects to posterior hypothalamic arousal systems. | the suprachiasmatic nucleus (scn) temporally organizes behavior in part by sustaining arousal during the wake period of the sleep/wake cycle to consolidate adaptive waking behavior. in this study, we demonstrate direct projections from the scn, in both the rat and the human brains, to perikarya and proximal dendrites of two groups of posterior hypothalamic neurons with axonal projections that suggest they are important in the regulation of arousal, one producing hypocretins (hct) and the other m ... | 2001 | 11209963 |
| fos expression in orexin neurons varies with behavioral state. | the neuropeptide orexin (also known as hypocretin) is hypothesized to play a critical role in the regulation of sleep-wake behavior. lack of orexin produces narcolepsy, which is characterized by poor maintenance of wakefulness and intrusions of rapid eye movement (rem) sleep or rem sleep-like phenomena into wakefulness. orexin neurons heavily innervate many aminergic nuclei that promote wakefulness and inhibit rem sleep. we hypothesized that orexin neurons should be relatively active during wake ... | 2001 | 11222656 |
| discharge profiles of ventral tegmental area gaba neurons during movement, anesthesia, and the sleep-wake cycle. | although mesolimbic dopamine (da) transmission has been implicated in behavioral and cortical arousal, da neurons in the ventral tegmental area (vta) and substantia nigra pars compacta (snc) are not significantly modulated by anesthetics or the sleep-wake cycle. however, vta and sn non-da neurons evince increased firing rates during active wakefulness (aw) and rapid eye movement (rem) sleep, relative to quiet wakefulness. here we describe the effects of movement, select anesthetics, and the slee ... | 2001 | 11222665 |
| prepro-orexin mrna levels in the rat hypothalamus, and orexin receptors mrna levels in the rat hypothalamus and adrenal gland are not influenced by the thyroid status. | orexins are two recently discovered neuropeptides that play an important role in the regulation of food intake and in the regulation of the sleep-wake cycle. in this work we examined the effects of thyroid hormones on prepro-ox expression in the rat hypothalamus, and oxrs expression in the rat hypothalamus and adrenal gland. hypo- and hyperthyroidism were induced in adult male rats, and the levels of hypothalamic prepro-ox and oxrs mrna, and adrenal oxrs mrna were determined using semiquantitati ... | 2001 | 11226638 |
| dual effects of melatonin on barbiturate-induced narcosis in rats. | melatonin affects the circadian sleep/wake cycle, but it is not clear whether it may influence drug-induced narcosis. sodium thiopenthal was administered intraperitoneally into male rats pre-treated with melatonin (0.05, 0.5, 5 and 50 mg/kg). melatonin pre-treatment affected in a dual manner barbiturate narcosis, however, no dose-effect correlation was found. in particular, low doses reduced the latency to and prolonged the duration of barbiturate narcosis. in contrast, the highest dose of melat ... | 2001 | 11226639 |
| sleep in the blind mole rat spalax ehrenbergi. | the mole rat, spalax ehrenbergi, is an interesting species for sleep because of its pronounced specialization to a fossorial life. these rodents spend most of their life-time underground, and are less exposed to many of the environmental stimuli and challenges that are common to non-fossorial rodents. a prominent adaptation is their blindness, which is due to an atrophy of the eyes. | 2001 | 11247050 |
| prenatal nicotine alters vigilance states and achr gene expression in the neonatal rat: implications for sids. | maternal smoking is a major risk factor for sudden infant death syndrome (sids). the mechanisms by which cigarette smoke predisposes infants to sids are not known. we examined the effects of prenatal nicotine exposure on sleep/wake ontogenesis and central cholinergic receptor gene expression in the neonatal rat. prenatal nicotine exposure transiently increased sleep continuity and accelerated sleep/wake ontogeny in the neonatal rat. prenatal nicotine also upregulated nicotinic and muscarinic cho ... | 2001 | 11247836 |
| differential sensitivity to the wake-promoting actions of norepinephrine within the medial preoptic area and the substantia innominata. | mapping studies were conducted to delineate the site(s) of action for the arousal-enhancing actions of norepinephrine (ne) within the basal forebrain region encompassing the medial preoptic area (mpoa) and the substantia innominata (si). varying doses of ne, the beta-agonist, isoproterenol, or the alpha1-agonist, phenylephrine, were infused into the mpoa or si in the resting rat. infusions of ne (4 nmol, 16 nmo/150 nl), isoproterenol (15 nmol/150 nl), and phenylephrine (40 nmol/250 nl) into the ... | 2001 | 11256440 |
| brain extracellular glucose assessed by voltammetry throughout the rat sleep-wake cycle. | in the present study, cortical extracellular levels of glucose were monitored for the first time throughout the sleep-wake states of the freely moving rat. for this purpose, polygraphic recordings (electroencephalogram of the fronto-occipital cortices and electromyogram of the neck muscles) were achieved in combination with differential normal pulse voltammetry (dnpv) using a specific glucose sensor. data obtained reveal that the basal extracellular glucose concentration in the conscious rat is ... | 2001 | 11298804 |
| auditory evoked potentials from auditory cortex, medial geniculate nucleus, and inferior colliculus during sleep-wake states and spike-wave discharges in the wag/rij rat. | click auditory evoked potentials (aep) were simultaneously recorded from the auditory cortex (acx), the medial geniculate nucleus (mgn), and the inferior colliculus (ic) in the freely moving wag/rij rat, to investigate state-dependent changes of the aep in different anatomical locations along the auditory pathway. | 2001 | 11306019 |
| deficiency of growth hormone-releasing hormone signaling is associated with sleep alterations in the dwarf rat. | the somatotropic axis, and particularly growth hormone-releasing hormone (ghrh), is implicated in the regulation of sleep-wake activity. to evaluate sleep in chronic somatotropic deficiency, sleep-wake activity was studied in dwarf (dw/dw) rats that are known to have a defective ghrh signaling mechanism in the pituitary and in normal lewis rats, the parental strain of the dw/dw rats. in addition, expression of ghrh receptor (ghrh-r) mrna in the hypothalamus/preoptic region and in the pituitary w ... | 2001 | 11306643 |
| microdialysis perfusion of 5-ht into hypoglossal motor nucleus differentially modulates genioglossus activity across natural sleep-wake states in rats. | 1. serotonin (5-hydroxytryptamine, 5-ht) excites hypoglossal (xii) motoneurons in reduced preparations, and it has been suggested that withdrawal of 5-ht may underlie reduced genioglossus (gg) muscle activity in sleep. however, systemic administration of 5-ht agents in humans has limited effects on gg activity. whether 5-ht applied directly to the xii motor nucleus increases gg activity in an intact preparation either awake or asleep has not been tested. 2. the aim of this study was to develop a ... | 2001 | 11306665 |
| effects of prolonged wakefulness on c-fos and ap1 activity in young and old rats. | recent studies have demonstrated that the immediate-early gene c-fos is induced in neuronal populations responsible for specific sleep-wake states. the induction of this gene may be functionally relevant to sleep homeostasis since without the gene mice (c-fos null) take longer to fall asleep and have a selective reduction in slow-wave sleep. this suggests that a build-up of c-fos during wakefulness increases the drive to sleep and lack of c-fos is associated with reduced sleep. sleep also has an ... | 2001 | 11311986 |
| modeling daily and subdaily cycles in rat sleep data. | we developed a statistical model for rat sleep-wake behavior over the 24-hour day; this model could be used for animals exposed to shorter cycles of light and dark conditions. rat behavior was classified either as "wake" or "sleep," as determined by analysis of electrophysiological data. the proposed model consists of three parts: the first two explain cyclic effects relating to the lighting conditions, whereas the last part reflects any acyclic effect. hypothesis tests were conducted on the mag ... | 1999 | 11315031 |
| rat strains that differ in corticotropin-releasing hormone production exhibit different sleep-wake responses to interleukin 1. | corticotropin-releasing hormone (crh) is a mediator of responses to a variety of stressors, including immune challenge. crh and the hypothalamic-pituitary-adrenal (hpa) axis constitute a negative feedback mechanism for actions of immunomodulators, such as interleukin (il) 1. crh is a potent inducer of waking, whereas il-1 induces slow-wave sleep (sws). we hypothesize that the complex changes in sleep-wake behavior during immune challenge are mediated in part by crh and its antagonism of il-1-ind ... | 2001 | 11340341 |
| on-line detection of sleep-wake states and application to produce intermittent hypoxia only in sleep in rats. | sleep-disordered breathing is associated with adverse clinical consequences such as daytime sleepiness and hypertension. the mechanisms behind these associations have been studied in animal models, especially rats, but intermittent stimuli such as hypoxia have been applied without reference to sleep-wake states. to determine mechanisms underlying the adverse physiological consequences of stimuli associated with sleep-disordered breathing requires criteria for detection of sleep-wake states on-li ... | 2001 | 11356775 |
| selected contribution: regulation of sleep-wake states in response to intermittent hypoxic stimuli applied only in sleep. | recurrent sleep-related hypoxia occurs in common disorders such as obstructive sleep apnea (osa). the marked changes in sleep after treatment suggest that stimuli associated with osa (e.g., intermittent hypoxia) may significantly modulate sleep regulation. however, no studies have investigated the independent effects of intermittent sleep-related hypoxia on sleep regulation and recovery sleep after removal of intermittent hypoxia. ten rats were implanted with telemetry units to record the electr ... | 2001 | 11356818 |
| pontine injections of nitric oxide synthase inhibitor l-name consolidate episodes of rem sleep in the rat. | dorsal mesopontine cholinergic neurons control rapid eye movement sleep (rems) and wakefulness and contain nitric oxide (no) synthase. to assess whether local inhibition of no synthase has distinct effects on sleep, n-nitro-l-arginine methyl ester, an no synthesis inhibitor (l-name, 80 mm), carbachol, a cholinergic agonist (2, 10 or 50 mm), or saline were microinjected (120-200 nl) into the dorsal mesopontine tegmentum in rats. sleep-wake cycles were monitored during the subsequent 6 h periods. ... | 1998 | 11382856 |
| sleep-wake and eeg effects following adenosine a1 agonism and antagonism: similarities and interactions with sleep-wake and eeg effects following a serotonin reuptake inhibitor in rats. | adenosine is currently being investigated as a possible mediator of a homeostatic sleep need. reports from different laboratories suggest that both adenosine a1 agonists and selective serotonin reuptake inhibitors (ssri) increase deep slow wave sleep (sws-2) after an interval. in this study, the sleep-wake effects of the adenosine a1 agonist n6-cyclopentyladenosine (cpa) and the ssri zimeldine are directly compared in the same animals. since the sws-2 increase following ssris may be secondary to ... | 1998 | 11382868 |
| rem sleep enhancement due to rhythmical auditory stimulation in the rat. | from a physiological viewpoint, rem sleep (rems) is a period during which homeostatic physiological regulations are impaired. in the rat, rems occurs in two forms respectively characterized by episodes separated by long intervals (single rems episodes) and by episodes which have short intervals and occur in sequences (rems clusters). since the partition of rems in the form of either single or clustered episodes may reveal how the rems drive and body homeostatic processes interact in the control ... | 2001 | 11399328 |
| sleep and memory deficits in the rat produced by experimental infection with trypanosoma cruzi. | we investigated whether the infection with trypanosoma cruzi in rats could produce functional alterations of the central nervous system. the experimental group received an injection of 150,000 trypomastigotes / rat, whereas the control group received a saline injection. spontaneous alternation behavior (sab) tests and sleep-wake cycle recordings were obtained at the end of the parasitaemia. results showed that the infected animals had significant sleep impairments, as denoted by an increase in t ... | 2001 | 11403959 |
| sleep is differently modulated by basal forebrain gaba(a) and gaba(b) receptors. | there is evidence that gaba plays a major role in sleep regulation. gaba(a) receptor agonists and different compounds interacting with the gaba(a) receptor complex, such as barbiturates and benzodiazepines, can interfere with the sleep/wake cycle. on the other hand, there is very little information about the possible role of gaba(b) receptors in sleep modulation. the nucleus basalis of meynert (nbm), a cholinergic area in the basal forebrain, plays a pivotal role in the modulation of sleep and w ... | 2001 | 11404291 |
| the role of the central nervous system in nacl-sensitive hypertension in spontaneously hypertensive rats. | the central and peripheral nervous system is typically considered to be a short-term modifier of sympathetic nervous system activity, but several lines of evidence suggest that they contribute to chronic elevation of arterial pressure in at least some forms of hypertension. our studies focus on the mechanisms underlying nacl-sensitive hypertension in the spontaneously hypertensive rat (shr). when these rats are fed a high nacl diet, their arterial pressure rapidly increases and is maintained abo ... | 2001 | 11411751 |
| contrasting effects of ibotenate lesions of the paraventricular nucleus and subparaventricular zone on sleep-wake cycle and temperature regulation. | the suprachiasmatic nucleus (scn), the circadian pacemaker for the brain, provides a massive projection to the subparaventricular zone (spz), but the role of the spz in circadian processes has received little attention. we examined the effects on circadian rhythms of sleep, body temperature, and activity in rats of restricted ibotenic acid lesions of the ventral or dorsal spz that spared the immediately adjacent paraventricular hypothalamic nucleus (pvh) and the scn. ventral spz lesions caused p ... | 2001 | 11425913 |
| orexins: effects on behavior and localisation of orexin receptor 2 messenger ribonucleic acid in the rat brainstem. | the orexins are neuropeptides originally reported to be involved in the stimulation of food intake. however, analysis of orexin immunoreactive fibres have revealed the densest innervation in brain sites involved in arousal and sleep-wake control, notably the noradrenergic locus coeruleus, an area that also expresses orexin receptor 1 (ox1r) messenger rna (mrna). we report here that, in the rat, a single intracerebroventricular injection of orexin a (1 and 3 nmol) or orexin b (3 nmol), during the ... | 2001 | 11430882 |
| firing rates of hippocampal neurons are preserved during subsequent sleep episodes and modified by novel awake experience. | what determines the firing rate of cortical neurons in the absence of external sensory input or motor behavior, such as during sleep? here we report that, in a familiar environment, the discharge frequency of simultaneously recorded individual ca1 pyramidal neurons and the coactivation of cell pairs remain highly correlated across sleep-wake-sleep sequences. however, both measures were affected when new sets of neurons were activated in a novel environment. nevertheless, the grand mean firing ra ... | 2001 | 11470910 |
| extracellular serotonin variations during vigilance states in the preoptic area of rats: a microdialysis study. | numerous studies have shown that serotonergic transmission decreases from waking (w) to slow wave sleep (sws) to paradoxical sleep (ps), suggesting an active role of serotonin (5-ht) in w but not in sleep. conversely, the inhibition of 5-ht activity produces insomnia. this insomnia can be reversed by injections of 5-hydroxytryptophan in the preoptic area (poa), suggesting that 5-ht is necessary in this cerebral structure for sleep. using microdialysis, we studied, 5-ht variations in the poa of r ... | 2001 | 11489253 |
| arousal effect of orexin a depends on activation of the histaminergic system. | orexin neurons are exclusively localized in the lateral hypothalamic area and project their fibers to the entire central nervous system, including the histaminergic tuberomammillary nucleus (tmn). dysfunction of the orexin system results in the sleep disorder narcolepsy, but the role of orexin in physiological sleep-wake regulation and the mechanisms involved remain to be elucidated. here we provide several lines of evidence that orexin a induces wakefulness by means of the tmn and histamine h(1 ... | 2001 | 11493714 |
| comparative effects of melatonin, zolpidem and diazepam on sleep, body temperature, blood pressure and heart rate measured by radiotelemetry in wistar rats. | the role of melatonin (mlt) in mediating the sleep-wake cycle has been previously suspected of indicating that this substance could be a candidate for a new generation of hypnotics. | 2001 | 11498719 |
| the influence of subchronic administration of the neurosteroid allopregnanolone on sleep in the rat. | the endogenous neurosteroid allopregnanolone has recently been demonstrated to have somnogenic properties that are very similar to those of other agonistic modulators of gaba(a) receptors, especially of short-acting benzodiazepines. short-acting benzodiazepines are established to rapidly lose their hypnotic effect upon repeated administration. to investigate the tolerance potential of allopregnanolone, we assessed sleep-wake behavior in rats during subchronic treatment (once daily for five days) ... | 2001 | 11557171 |
| similar genetic mechanisms may underlie sleep-wake states in neonatal and adult rats. | genetic differences in the characteristics of sleep-wake states in adult animals offer a potential window for examining how the neonatal and adult behavioural states are related to one another. our recent finding that adult wistar-kyoto (wky) rats show pronounced genetic differences in sleep-wake patterns relative to the wistar (wis) control strain led us to investigate the relationship between these behavioural states in neonates and adults in a longitudinal study in these two strains of rats. ... | 2001 | 11568642 |
| circadian rhythms and sleep have additive effects on respiration in the rat. | 1. we tested two hypotheses: that respiration and metabolism are subject to circadian modulation in wakefulness, non-rapid-eye-movement (nrem) sleep and rapid-eye-movement (rem) sleep; and that the effects of sleep on breathing vary as a function of time of day. 2. electroencephalogram (eeg), neck electromyogram (emg) and abdominal body temperature (t(b)) were measured by telemetry in six male sprague-dawley rats. the eeg and emg were used to identify sleep-wake states. ventilation (v(i)) and me ... | 2001 | 11579171 |
| developmental alcohol and circadian clock function. | studies in rats found that alcohol exposure during the early postnatal period, particularly during the brain-growth-spurt period, can result in cell loss in various brain regions and persistent behavioral impairments. some investigators have speculated that the body's internal clock, which is located in the suprachiasmatic nuclei (scn) in the brain, may also be affected by developmental alcohol exposure. for example, alcohol-induced damage to the scn cells and their function could result in dist ... | 2001 | 11584552 |
| excitation of the pedunculopontine tegmental nmda receptors induces wakefulness and cortical activation in the rat. | microinjection of the excitatory amino acid, l-glutamate into the brainstem pedunculo pontine tegmentum (ppt) has been shown to induce wakefulness, however, it has been unclear that receptors mediate this effect. the aim of this study was to test the hypothesis that in the ppt, l-glutamate induces cortical activation and wakefulness via activation of nmda receptors. to test this hypothesis, three sets of micro-injections into the ppt were carried out on two different groups of rats that were the ... | 2001 | 11599007 |
| wake-promoting and sleep-suppressing actions of hypocretin (orexin): basal forebrain sites of action. | the hypocretins (orexins) are a newly identified peptide family comprised of two peptides, hypocretin-1 and hypocretin-2. recent observations suggest an involvement of these peptides in the regulation of behavioral state. for example, these peptides are found in a variety of brain regions associated with the regulation of forebrain neuronal and behavioral activity states. furthermore, when infused into the lateral ventricles in awake animals, hypocretin-1 elicits increased duration of waking bey ... | 2001 | 11682157 |
| central and baroreflex control of heart rate during the wake-sleep cycle in rat. | spontaneous fluctuations in heart period (hp) and mean arterial pressure (map) make it possible to evaluate baroreceptor-heart rate reflex sensitivity (brs). 30-s sequences of hp and map beat-to-beat values were considered in the different wake-sleep states (wake, w; quiet sleep, qs; active sleep, as) in rats to assess whether 1) brs changes between states and 2) the different indexes supply consistent brs measures. brs indexes were calculated according to validated literature procedures as regr ... | 2001 | 11683478 |
| fluctuation of extracellular hypocretin-1 (orexin a) levels in the rat in relation to the light-dark cycle and sleep-wake activities. | hypocretins/orexins are neuropeptides implicated in sleep regulation and the sleep disorder narcolepsy. in order to examine how hypocretin activity fluctuates across 24 h with respect to the sleep-wake cycle, we measured changes in extracellular hypocretin-1 levels in the lateral hypothalamus and medial thalamus of freely moving rats with simultaneous sleep recordings. hypocretin levels exhibited a robust diurnal fluctuation; levels slowly increased during the dark period (active phase), and dec ... | 2001 | 11683899 |
| acute effects of melatonin on spontaneous and picrotoxin-evoked sleep-wake behaviour in the rat. | various studies indicate that exogenous melatonin has hypnotic properties in humans, which may be mediated by its influence on the circadian timing system or direct sleep-promoting actions, e.g. through a modulation of gabaergic transmission. the aim of the present placebo-controlled study was to examine the effects of melatonin on sleep in rats and the contribution of gamma-aminobutyric acid (gaba)a receptors. sleep-wake behaviour was assessed in nine rats after intraperitoneal (i.p.) administr ... | 2001 | 11696074 |
| further definition of the effect of corticosterone on the sleep-wake pattern in the male rat. | it is well known that the activation of the hypothalamic-pituitary-adrenal (hpa) axis can induce alterations in the sleep-wake pattern. corticotropin-releasing factor (crf), adrenocorticotropin, and corticosterone are involved in the activation of the axis and each one of them has shown an effect on wakefulness and sleep. nevertheless, concerning corticosterone, the picture is still controversial. in the present study, we analyzed the effects of a low (lc, 0.2 mg), medium (mc, 2 mg), and high (h ... | 2001 | 11701201 |
| electrophysiological analysis of suprachiasmatic nucleus projections to the ventrolateral preoptic area in the rat. | the circadian pacemaker housed in the suprachiasmatic nucleus (scn) synchronizes daily sleep-wake cycles, presumably by modulating the sleep-wake regulatory system, including ventrolateral preoptic area (vlpo) neurons. we used whole-cell patch-clamp recording to study the projections from the scn to the vlpo in horizontal slices of rat hypothalamus. single-pulse stimulation of the scn region elicited postsynaptic currents (pscs) in 20 of 66 neurons (30%) recorded within the vlpo region as verifi ... | 2001 | 11703455 |
| an adenosine a2a agonist increases sleep and induces fos in ventrolateral preoptic neurons. | considerable evidence indicates that adenosine may be an endogenous somnogen, yet the mechanism through which it promotes sleep is unknown. adenosine may act via a1 receptors to promote sleep, but an a2a receptor antagonist can block the sleep induced by prostaglandin d(2). we previously reported that prostaglandin d(2) activates sleep-promoting neurons of the ventrolateral preoptic area, and we hypothesized that an a2a receptor agonist also should activate these neurons. rats were instrumented ... | 2001 | 11720788 |
| orexin a and b evoke noradrenaline release from rat cerebrocortical slices. | 1. orexin a and b, recently identified in the rat hypothalamus are endogenous neuropeptide agonists for the g-protein coupled orexin-1 (ox1) and orexin-2 (ox2) receptors. 2. in the present study, we have examined the effects of orexin a, b and raised extracellular k(+) on noradrenaline release from the rat cerebrocortical slice. we have compared this with other sleep-wake-related (excitatory) neurotransmitters; dopamine, glutamate, serotonin and histamine. 3. neurotransmitter release studies wer ... | 2001 | 11724752 |
| variations in extracellular monoamines in the prefrontal cortex and medial hypothalamus after modafinil administration: a microdialysis study in rats. | the role of brain amines in mediating the effects of the wake-promoting agent modafinil, used in the treatment of sleepiness associated with narcolepsy is still uncertain. therefore we studied the effects of modafinil on extracellular serotonin (5-ht), dopamine (da) and noradrenaline (na), in rat prefrontal cortex and in the medial hypothalamus area. modafinil (128 mg/kg i.p.) significantly increased waking in the first 4 h of eeg sleep recording. this cortical and behavioral activation was asso ... | 2001 | 11733706 |
| chemosensitivity of serotonergic neurons in the rostral ventral medulla. | the medullary raphé contains two subtypes of chemosensitive neuron: one that is stimulated by acidosis and another that is inhibited. both types of neuron are putative chemoreceptors, proposed to act in opposite ways to modulate respiratory output and other ph sensitive brain functions. in this review, we will discuss the cellular properties of these chemosensitive raphé neurons when studied in vitro using brain slices and primary dissociated cell culture. quantification of chemosensitivity of r ... | 2001 | 11738653 |
| sleep of transgenic mice producing excess rat growth hormone. | the effects of chronic excess of growth hormone (gh) on sleep-wake activity was determined in giant transgenic mice in which the metallothionein-1 promoter stimulates the expression of rat gh (mt-rgh mice) and in their normal littermates. in the mt-rgh mice, the time spent in spontaneous non-rapid eye movement sleep (nrems) was enhanced moderately, and rapid eye movement sleep (rems) time increased greatly during the light period. after a 12-h sleep deprivation, the mt-rgh mice continued to slee ... | 2002 | 11742825 |
| gaba(b) receptors in the median raphe nucleus: distribution and role in the serotonergic control of hippocampal activity. | previous studies have shown that serotonergic neurons of the median raphe nucleus have a suppressive effect on theta synchronization in the hippocampus. median raphe lesion, suppression of 5-ht neuronal activity by administration of gaba(a) receptor antagonist or by glutamate blockade or depletion produced long-lasting non-interrupted hippocampal theta in freely behaving rats independent of behavior and in rats anesthetized with urethane. serotonergic neurons show a characteristic sleep-wake pat ... | 2002 | 11784704 |
| sleep-waking discharge patterns of neurons recorded in the rat perifornical lateral hypothalamic area. | the perifornical lateral hypothalamic area (pf-lha) has been implicated in the control of several waking behaviours, including feeding, motor activity and arousal. several cell types are located in the pf-lha, including projection neurons that contain the hypocretin peptides (also known as orexins). recent findings suggest that hypocretin neurons are involved in sleep-wake regulation. loss of hypocretin neurons in the human disorder narcolepsy is associated with excessive somnolence, cataplexy a ... | 2002 | 11790824 |
| effects of sleep-wake state on the genioglossus vs.diaphragm muscle response to co(2) in rats. | the effects of sleep on the ventilatory responses to hypercapnia have been well described in animals and in humans. in contrast, there is little information for genioglossus (gg) responses to a range of co(2) stimuli across all sleep-wake states. given the notion that sleep, especially rapid eye movement (rem) sleep, may cause greater suppression of muscles with both respiratory and nonrespiratory functions, this study tests the hypothesis that gg activity will be differentially affected by slee ... | 2002 | 11796705 |
| orexins and adipoinsular axis function in the rat. | orexin a and b are recently identified as peptides that are derived from the same precursor and their expression is highly specifically localized in neurons located in the lateral hypothalamic area, a region implicated in the feeding behaviour. these peptides appear to be a part of a complex circuit that integrates the aspects of energy metabolism, cardiovascular function, hormone homeostasis and sleep/wake behaviours. the functional linking of orexins with leptin and insulin suggests the possib ... | 2002 | 11830279 |
| mesolimbic dopaminergic system is involved in diurnal blood pressure regulation. | parkinson's disease (pd) patients with autonomic failure show no nocturnal decrease in blood pressure (bp). at present, it is not clear if this symptom is attributable to the disturbance of the dopaminergic (da) system that is responsible for pd. in the present study, we determined that the mesolimbic da system is involved in diurnal profiles of the mean bp (mbp) by destroying the a10 da system in rats with 6-hydroxydopamine. in control rats, a clear dip in the mbp and heart rate (hr) occurs dur ... | 2002 | 11844487 |
| orexin receptor-1 (ox-r1) immunoreactivity in chemically identified neurons of the hypothalamus: focus on orexin targets involved in control of food and water intake. | the neuropeptides orexin-a and orexin-b are produced in neurons of the lateral hypothalamic area and have been implicated to be involved in the regulation of food/water intake and sleep-wake control. the orexins act at two different g-protein-coupled orexin receptors (ox-r1 and ox-r2) that are derived from separate genes and expressed differentially throughout the central nervous system. in the present study, we have used a polyclonal antipeptide antiserum to analyse in detail the distribution o ... | 2002 | 11849298 |
| expression of lipopolysaccharide binding protein and its receptor cd14 in experimental alcoholic liver disease. | to evaluate the relationship between the expression of lipopolysaccharides (lps) binding protein (lbp) and cd14 mrna and the severity of liver injury in alcohol-fed rats. | 2001 | 11854912 |
| the sk-n-mc cell line expresses an orexin binding site different from recombinant orexin 1-type receptor. | orexin a and b (also known as hypocretins), two recently discovered neuropeptides, play an important role in food intake, sleep/wake cycle and neuroendocrine functions. orexins are endogenous ligands of two g-protein-coupled receptors, termed ox1 and ox2. this work presents the first short orexin a and b analogues, orexin a 23-33 and orexin b 18-28, with high affinity (119 +/- 49 and 49 +/- 23 nm) for ox1 receptors expressed on sk-n-mc cells and indicates the importance of the c-terminal part of ... | 2002 | 11856342 |
| ultradian rhythmicity of ghrelin secretion in relation with gh, feeding behavior, and sleep-wake patterns in rats. | ghrelin, an endogenous ligand for the ghs receptor, stimulates gh secretion and gastrointestinal motility and has orexigenic effects. in this study, the relationships between ghrelin, gh secretion, feeding behavior, and sleep-wake patterns were investigated in adult male rats. the half-life of exogenous ghrelin (10 microg i.v.) in plasma was about 30 min. repeated administration of ghrelin at 3- to 4-h intervals (one during lights-on and two during lights-off periods) increased gh release and fe ... | 2002 | 11897692 |
| [influence of cerebral and peripheral nitric oxide on sleep/wake cycle in the rat]. | through a polygraphic and pharmacological approach conducted in the rat, it is established that l-name (n-nitro-l-arginine methyl ester; an inhibitor of the endothelial and neuronal no-synthases), administered intraperitoneally (i.p., 100 mg/kg) increases significantly slow wave sleep (sws) and paradoxical sleep (ps). on the contrary, 7-ni (7-nitro-indazole; an inhibitor of the neuronal no-synthase), when administered locally in the nrd (n. raphe dorsalis), decreases ps without sws changes. fina ... | 2001 | 11924033 |
| [variations of hypothalamic and cortical prostaglandins and monoamines reveal transitions in arousal states: microdialysis study in the rat]. | brain microdialysis coupled with eeg recording allowed us to track dynamic neurochemical changes every 3 or 6 minutes in relation to sleep/wake cycles. we chose to investigate prostaglandins (pg) and monoamines (catecholamines, serotonin and metabolites) because of their respective role in the states of vigilance, mainly suggested by pharmacological approaches, and because of the known interactions between pgs and monoamines. we focused on the paraventricular and ventromedial nuclei of the hypot ... | 2001 | 11924034 |
| distinct sleep-wake stages in rats depend differentially on age. | the objective was to study age-related changes in sleep-wake stages in the rat by using precise polyphysiograph criteria for stage identification. cortical and hippocampal electroencephalogram, and ocular and myographic activities were recorded in young, middle-aged, and old male wistar rats to define 6 stages: active and quiet wake (aw, qw); light and deep slow wave sleep (sws: s1, s2); intermediate stage of sleep (is); and paradoxical sleep (ps). the old rats displayed a decrease in s1, s2, an ... | 2002 | 11958861 |
| co2 dialysis in nucleus tractus solitarius region of rat increases ventilation in sleep and wakefulness. | to evaluate the function of widely distributed central chemoreceptors during sleep and wakefulness in the rat, we focally stimulate single chemoreceptor sites during naturally occurring sleep-wake cycles by microdialysis of artificial cerebrospinal fluid equilibrated with 25% co2. in retrotrapezoid nucleus, this increased ventilation (tidal volume) by 24% only in wakefulness (li a, randall m, and nattie e. j appl physiol 87: 910-919, 1999). in caudal medullary raphé, it increased ventilation (fr ... | 2002 | 11960965 |
| melatonin modulates [3h]serotonin release in the rat hippocampus: effects of circadian rhythm. | serotonin (5-ht) participates as a neurotransmitter in the control of the circadian sleep/wake rhythm, feeding and sexual behaviours, and emotional and affective states. the present study investigated whether melatonin affects the circadian rhythm of 5-ht neurotransmission in the hippocampus, a major target for serotoninergic antidepressants. the present results show a daytime dependency of [3h]5-ht uptake insensitive to melatonin, with a peak from 14.00 h to 22.00 h and a trough from 02.00 h to ... | 2002 | 11999718 |
| pre- and post-natal protein malnutrition alters the effect of rapid eye movements sleep-deprivation by the platform-technique upon the electrocorticogram of the circadian sleep-wake cycle and its frequency bands in the rat. | selective deprivation of paradoxical (or rapid eye movements) sleep (rems) in protein malnourished young male rats, results in circadian and homeostatic alterations. by means of electrocorticographic recordings, we have examined the sleep-wake cycle as a functional maturity index, and its circadian and homeostatic mechanisms in prenatal (pm) and chronically (cm) protein malnourished young male rats. the effects of rapid eye movements sleep-deprivation (rems-d), by the platform technique in a "co ... | 2002 | 12000087 |
| the effect of restraint stress on paradoxical sleep is influenced by the circadian cycle. | it is well known that the physiological impact imposed by events or behaviors displayed during the waking period determines the way organisms sleep. among the situations known to affect sleep both in its duration and quality, stress has been widely studied and it is now admitted that its effects on sleep architecture depend on several factors specific to the stressor or the individual itself. although numerous reports have highlighted the prominent role of the circadian cycle in the physiologica ... | 2002 | 12020861 |
| the central nucleus of the amygdala and the wake-promoting effects of modafinil. | modafinil, a novel non-amphetamine stimulant recently approved for the treatment of narcolepsy, has been shown to increase waking in both animals and humans. however, its mechanism of action is currently unknown. earlier research into the brain structures responsible for the wake-producing actions of modafinil implicated the central nucleus of the amygdala (ace) as a possible site of action [neuroscience 87 (1998) 905-911; neurosci. lett. 241 (1998) 95-98]. the present experiments were designed ... | 2002 | 12031546 |
| assessment of spontaneously occurring periodic limb movements in sleep in the rat. | periodic limb movements in sleep (plms) are often associated with the restless legs syndrome (rls). although the dopaminergic system seems to be involved, the pathophysiology of plms and rls is still obscure. the objective of this study is to explore whether a plms-like phenomenon can be observed in rodents in order to elucidate the underlying mechanisms. | 2002 | 12039666 |
| in vivo microdialysis measures of extracellular norepinephrine in the rat amygdala during sleep-wakefulness. | norepinephrine (ne)-containing locus ceruleus (lc) has been known to participate in the regulation of the sleep-wake cycle according to the differential firing rate. the aim of this study was to know the change of extracellular ne level in the rat amygdala, which are reciprocally connected with lc, during sleep-wakefulness. extracellular ne levels in the rat amygdala were investigated during different stages of the sleep-waking cycle using in vivo microdialysis and polygraphic recording. dialysa ... | 2002 | 12068146 |
| circadian-dependent and circadian-independent behavioral actions of hypocretin/orexin. | the hypocretins/orexins modulate behavioral state as well as a variety of state-dependent behaviors. levels of hypocretin-1 and prepro-hypocretin mrna vary in a circadian fashion, suggesting that hypocretin neurotransmission may vary across the circadian cycle. to better assess the circadian dependency of the behavioral actions of hypocretin-1, the behavioral effects of intracerebroventricular hypocretin-1 administration (3.0 nmol/2 microl) were examined at differing portions of the circadian cy ... | 2002 | 12101045 |
| theoretical and practical considerations in the application of whole body plethysmography to sleep research. | the sleep-wake state has a profound influence on many, perhaps most, aspects of normal physiology and is strongly implicated in the mediation (or remediation) of impaired health and performance. many sleep disorders stem from abnormal respiratory anatomy or sleep-induced changes in respiratory control, underscoring the need for research into the effects of the sleep-wake state on respiratory control processes. whole body plethysmography is being increasingly used to study respiration in freely b ... | 2002 | 12111280 |
| role of corticotropin-releasing hormone in stressor-induced alterations of sleep in rat. | corticotropin-releasing hormone (crh) mediates responses to a variety of stressors. we subjected rats to a 1-h period of an acute stressor, physical restraint, and determined the impact on subsequent sleep-wake behavior. restraint at the beginning of the light period, but not the dark period, increased waking and reduced rapid eye movement sleep without dramatically altering slow-wave sleep (sws). electroencephalogram (eeg) slow-wave activity during sws and brain temperature were increased by th ... | 2002 | 12121853 |
| orexins in rat dorsal motor nucleus of the vagus potently stimulate gastric motor function. | orexins regulate food intake, arousal, and the sleep-wake cycle. they are synthesized by neurons in the lateral hypothalamus and project to autonomic areas in the hindbrain. orexin a applied to the dorsal surface of the medulla stimulates gastric acid secretion via a vagally mediated pathway. we tested the hypothesis that orexins in the dorsal motor nucleus (dmn) of the vagus regulate gastric motor function. multibarelled micropipette assemblies were used to administer vehicle, l-glutamate, orex ... | 2002 | 12121895 |
| novel object presentation affects sleep-wake behavior in rats. | sleep is suggested to be crucial for the processing and storage of new information. several learning tasks have been shown to increase the amount of rapid eye movement sleep (rems) with its typical theta activity (6-8 hz) relative to total sleep time. vice versa, rems deprivation is able to affect memory consolidation following some, but not all learning tasks. furthermore, recent studies have shown an increase of spindle activity (12-15 hz) within the electroencephalogram (eeg) of nonrems as we ... | 2002 | 12123855 |
| modulation of hypothalamic hypocretin/orexin mrna expression by glucocorticoids. | the orexins are peptides which were recently isolated from the rat hypothlamus. they play a role in energy homeostasis and regulation of feeding as well as in other functions such as the sleep-wake cycle. the involvement of glucocorticoids in stress processes as well as in body weight regulation is well known. in the present paper, we investigated the role of glucocorticoids on hypocretin (hcrt)/orexin (ox) pathway in sprague-dawley rats. we confirmed by in situ hybridization that prepro-hcrt/ox ... | 2002 | 12147238 |
| eeg spectra, behavioral states and motor activity in rats exposed to acetylcholinesterase inhibitor chlorpyrifos. | exposure to organophosphates (op) has been associated with sleep disorders such as insomnia and "excessive dreaming." the central mechanisms of these effects are not well understood. ops inhibit acetylcholinesterase (ache) activity, leading to a hyperactivity of the brain cholinergic systems that are involved in sleep regulation. we studied alterations in the eeg, behavioral states, motor activity and core temperature in rats orally administered with 10 or 40 mg/kg of the op insecticide chlorpyr ... | 2002 | 12175464 |
| melatonin microinjection into the medial preoptic area increases sleep in the rat. | a wide variety of hypnotic compounds including triazolam, pentobarbital, ethanol and adenosine have been reported to enhance sleep when microinjected into the medial preoptic area (mpa) of the anterior hypothalamus of the rat. it is uncertain whether the pineal hormone melatonin, which may alter sleep/wake physiology in mammals, acts at this site. a previous report has indicated that a more widespread injection of melatonin into the hypothalamus of the cat induces sleep. in the present study we ... | 2002 | 12175899 |
| the physiology and pharmacology of the orexins. | orexin-a and orexin-b are two peptides derived by proteolytic cleavage from a 130 amino acid precursor prepro-orexin, which recently were isolated from the rat hypothalamus. orexin-a is fully conserved across mammalian species, whilst rat and human orexin-b differ by 2 amino acids. these peptides bind to two g(q)-coupled receptors, termed ox(1) and ox(2). the receptors are 64% homologous and highly conserved across species. orexin-a is equipotent at ox(1) and ox(2), whilst orexin-b displays mode ... | 2002 | 12191593 |
| the crh1 receptor antagonist r121919 attenuates stress-elicited sleep disturbances in rats, particularly in those with high innate anxiety. | excessive corticotropin-releasing hormone (crh) secretion in limbic and prefrontal brain areas has been postulated to underly stress-related clinical conditions. studies in mice with deleted or pharmacologically compromised crh type 1 receptors (crh-r1) point to a key role of the crh/crh-r1 signaling cascade as a potential drug target. therefore, we compared the effect of a selective high affinity crh-r1 antagonist (r121919) on sleep-wake behavior in two rat lines selectively bred for either hig ... | 2002 | 12191624 |
| a low-noise flexible integrated system for recording and analysis of multiple electrical signals during sleep-wake states in rats. | a low-noise flexible system for the simultaneous recording and analysis of several electrical signals (eeg, ecg, emg, and diaphragm emg) from the same rat was constructed for studying changes in physiological functions during the sleep-wake cycle. the hardware in the system includes a multichannel amplifier, a video camera, a timer code generator, and a pc. a miniature buffer headstage with high-input impedance connected to a 6-channel amplifier was developed. all electrical activities devoid of ... | 2002 | 12191760 |
| eeg measurements by means of radiotelemetry after intracerebroventricular (icv) cannulation in rodents. | the utility of implanted radiotelemetry transmitters for the measurement of electroencephalogram (eeg), locomotor activity, body temperature and cardiovascular parameters has been well documented. this paper focuses on the methodology, of combining radiotelemetry with intracerebroventricular (icv) cannulation. the two excitatory neuropeptides, orexin-a and orexin-b, can only be given by icv injection, therefore we examined their effects on the normal sleep-wake cycle of rodents in the present st ... | 2002 | 12191761 |
| lactate in the brain of the freely moving rat: voltammetric monitoring of the changes related to the sleep-wake states. | cortical lactate was monitored voltammetrically in freely moving rats equipped with polygraphic electrodes. differential normal pulse voltammetric measurements were carried out using a lactate biosensor coated with lactate oxidase and cellulose acetate. changes occurring in lactate level were in keeping with sleep-wake states. during slow wave sleep (sws), the lactate level decreased significantly (-16.2%) vs. the spontaneous waking state (w) referenced to as 100%. during paradoxical sleep (ps), ... | 2002 | 12193189 |
| tonic rhythmic activity of rat cerebellar neurons. | simultaneous recordings of multiple single unit activity in both cerebral and cerebellar cortex, cortical eeg, and both nuchal and vibrissal emg were obtained in nine unrestrained rats. putative purkinje cells of the deep vermal cerebellar cortex exhibited rhythmic discharge of simple spikes with extremely low variability in interspike intervals for several hours. the highly rhythmic nature of spike discharge was remarkably stable across all states of sleep (both slow-wave and rapid eye movement ... | 2002 | 12195529 |
| sleep-waking discharge patterns of median preoptic nucleus neurons in rats. | several lines of evidence show that the preoptic area (poa) of the hypothalamus is critically implicated in the regulation of sleep. functionally heterogeneous cell groups with sleep-related discharge patterns are located both in the medial and lateral poa. recently a cluster of neurons showing sleep-related c-fos immunoreactivity was found in the median preoptic nucleus (mnpn). to determine the specificity of the state-related behaviour of mnpn neurons we have undertaken the first study of thei ... | 2002 | 12205198 |