| a quartet neural system model orchestrating sleep and wakefulness mechanisms. | physiological knowledge of the neural mechanisms regulating sleep and wakefulness has been advanced by the recent findings concerning sleep/wakefulness-related preoptic/anterior hypothalamic and perifornical (orexin-containing)/posterior hypothalamic neurons. in this paper, we propose a mathematical model of the mechanisms orchestrating a quartet neural system of sleep and wakefulness composed of the following: 1) sleep-active preoptic/anterior hypothalamic neurons (n-r group); 2) wake-active hy ... | 2006 | 16282204 |
| nuclear parcellation of certain immunohistochemically identifiable neuronal systems in the midbrain and pons of the highveld molerat (cryptomys hottentotus). | the present paper details our findings following immunohistochemical examination of the midbrain and pons of the highveld molerat (cryptomys hottentotus) using antibodies for vesicular acetylcholine transporter (cholinergic neurons), tyrosine hydroxylase (dopaminergic and noradrenergic neurons), and serotonin (serotonergic neurons). the aim was to see if, in this microphthalmic rodent that lacks a distinct circadian rhythm, the nuclei involved in aspects of visual processing and the sleep-wake c ... | 2006 | 16289497 |
| insomnia following hypocretin2-saporin lesions of the substantia nigra. | the neuropeptide hypocretin, also known as orexin, has been implicated in waking since its deletion leads to the sleep disorder narcolepsy. hypocretin neurons project to major arousal areas, and in an effort to determine which region is responsible for the changes in sleep-wake architecture we have developed the neurotoxin hypocretin2-saporin, which lesions hypocretin receptor bearing neurons. here, in rats, we investigate the effects of hypocretin2-saporin lesions of the substantia nigra and ve ... | 2006 | 16289583 |
| beneficial effects of regular exercise on sleep in old f344 rats. | with aging there is a significant decline in the normal architecture of sleep and a reduction in the diurnal amplitude of core body temperature. regular moderate exercise has been shown to have a positive impact in the elderly and here we investigate whether sleep-wake patterning can also be improved. young (3 months) and old (22 months) f344 rats were exercised once a day for 50min at night onset over an 8-week period. thereafter, polysomnographic recordings were obtained immediately after exer ... | 2006 | 16309796 |
| smad-dependent alterations of ppt cholinergic neurons as a pathophysiological mechanism of age-related sleep-dependent memory impairments. | in humans, memory impairments are highly prevalent in the aged population, but their functional and structural origins are still unknown. we hypothesized that circadian rhythm alterations may predict spatial memory impairment in aged rats. we demonstrate an association between sleep/wake circadian rhythm disturbances (non-rem sleep fragmentation) and spatial memory impairments in aged rats. we show by light and electron microscopy that these age-related disruptions in circadian rhythm and spatia ... | 2006 | 16316709 |
| cyclic nucleotides modulate genioglossus and hypoglossal responses to excitatory inputs in rats. | previous studies modulating pharyngeal muscle activity with pharmacologic approaches have targeted membrane receptors on pharyngeal motoneurons. whether modulation of intracellular pathways can increase pharyngeal muscle activity, however, has not been investigated but is relevant to pharmacologic treatments of obstructive sleep apnea. | 2006 | 16322643 |
| a versatile, low-cost adaptor for stereotaxic and electrophysiologic spinal preparations in juvenile and adult rodents. | rats and mice provide excellent models for normal spinal cord physiology, traumatic spinal cord injury, and various disease states. alternative and improved methodologies for experimental spinal preparations are desirable, particularly in the wake of expanding neuroscience technology, such as the diverse array of transgenic mice now available, and exciting new therapeutic approaches, including transplantation and gene therapy. this report describes a simple, low-cost instrument for spinal prepar ... | 2005 | 16325015 |
| further structure-activity relationship studies of piperidine-based monoamine transporter inhibitors: effects of piperidine ring stereochemistry on potency. identification of norepinephrine transporter selective ligands and broad-spectrum transporter inhibitors. | 4-(4-chlorophenyl)piperidine analogues each bearing a thioacetamide side chain appendage similar to that found in the wake-promoting drug modafinil have been synthesized. the transporter inhibitory activity of both the cis and trans isomers of these 3,4-disubstituted piperidines in both their (+)- and (-)-enantiomeric forms was determined. these studies reveal that the (-)-cis analogues exhibit dopamine transporter/norepinephrine transporter (dat/net) selectivity as was previously reported for t ... | 2005 | 16335921 |
| immunolocalization of ecto-nucleoside triphosphate diphosphohydrolase 3 in rat brain: implications for modulation of multiple homeostatic systems including feeding and sleep-wake behaviors. | three anti-peptide antisera were raised against three distinct amino acid sequences of ecto-nucleoside triphosphate diphosphohydrolase 3 (ntpdase3), characterized by western blot analyses, and used to determine the distribution of ntpdase3 protein in adult rat brain. the three antisera all yielded similar immunolocalization data, leading to increased reliability of the results obtained. unlike ntpdase1 and ntpdase2, ntpdase3 immunoreactivity was detected exclusively in neurons. immunoreactivity ... | 2006 | 16338080 |
| vasopressin induces depolarization and state-dependent firing patterns in rat thalamic paraventricular nucleus neurons in vitro. | the thalamic midline paraventricular nucleus (pvt) is prominently innervated by vasopressin-immunoreactive neurons from the suprachiasmatic nucleus (scn), site of the brain's biological clock. using patch-clamp recordings in slice preparations taken from wistar rats during the subjective day, we examined 90 pvt neurons for responses to bath-applied avp (0.5-2 microm; 1-3 min). in current clamp at resting membrane potentials (-65 +/- 1 mv), pvt neurons displayed low-threshold spikes (ltss) and bu ... | 2006 | 16339383 |
| nitric oxide from the laterodorsal tegmental neurons: its possible retrograde modulation on norepinephrine release from the axon terminal of the locus coeruleus neurons. | nitric oxide released from the cholinergic neurons in the pons may play important roles in sleep-wake regulation. however, there are few reports demonstrating the mechanisms of nitric oxide release in the cholinergic neurons in the pons. the present study investigated the effects of drug delivery of n-methyl-d-aspartic acid on nitric oxide and the neurotransmitters released in the laterodorsal tegmental nucleus (ldt), one of the major cholinergic cell groups in the pons, in rats by in vivo micro ... | 2006 | 16368196 |
| afferents to the orexin neurons of the rat brain. | emotions, stress, hunger, and circadian rhythms all promote wakefulness and behavioral arousal. little is known about the pathways mediating these influences, but the orexin-producing neurons of the hypothalamus may play an essential role. these cells heavily innervate many wake-promoting brain regions, and mice lacking the orexin neurons have narcolepsy and fail to rouse in response to hunger (yamanaka et al. [2003] neuron 38:701-713). to identify the afferents to the orexin neurons, we first i ... | 2006 | 16374809 |
| neuropeptide-y y2-receptor agonist, pyy3-36 promotes non-rapid eye movement sleep in rat. | pyy3-36 is a major component of the gut-brain axis and peripheral administration has been reported to exert significant effects on feeding, brain function and is more selective for neuropeptide y2 receptor. therefore, we investigated the effects of nocturnal intraperitoneal administration of single doses of pyy3-36 (30 and 100 microg/kg i.p.) on food intake, water intake and the sleep-wake cycle in rats. sleep recordings were carried out in male sprague-dawley rats implanted with cortical electr ... | 2006 | 16378653 |
| age-related changes in adenosine metabolic enzymes in sleep/wake regulatory areas of the brain. | the impact of age on the enzymatic activities of adenosine metabolic enzymes, i.e., adenosine deaminase, adenosine kinase, cytosolic- and ecto-5'-nucleotidase have been assessed in the brain sleep/wake regulatory areas of young, intermediate and old rats (2, 12 and 24 months, respectively). there were significant spatial differences in the distribution of enzymes of adenosine metabolism in the brain. age did not impact on the enzymatic activity of adenosine deaminase. adenosine kinase activity i ... | 2006 | 16399217 |
| identification of wake-active dopaminergic neurons in the ventral periaqueductal gray matter. | recent evidence suggests that dopamine plays an important role in arousal, but the location of the dopaminergic neurons that may regulate arousal remains unclear. it is sometimes assumed that the dopaminergic neurons in the ventral tegmental area that project to the prefrontal cortex and striatum may regulate the state of arousal; however, the firing of these dopaminergic neurons does not correlate with overall levels of behavioral wakefulness. we identified wake-active dopaminergic neurons by c ... | 2006 | 16399687 |
| serotonergic neuron diversity: identification of raphe neurons with discharges time-locked to the hippocampal theta rhythm. | the serotonergic system plays a key role in the regulation of brain states, and many of the known features of serotonergic neurons appear to match this function. midbrain raphe nuclei provide a diffuse projection to all regions of the forebrain, and raphe neurons exhibit a slow metronome-like activity that sets the ambient levels of serotonin across the sleep-wake cycle. serotonergic cells have also been implicated, however, in a variety of more specific functions that can hardly be related to t ... | 2006 | 16418294 |
| inhibition of caspase-1 in rat brain reduces spontaneous nonrapid eye movement sleep and nonrapid eye movement sleep enhancement induced by lipopolysaccharide. | evidence suggests that il-1beta is involved in promoting physiological nonrapid eye movement (nrem) sleep. il-1beta has also been proposed to mediate nrem sleep enhancement induced by bacteria or their components. mature and biologically active il-1beta is cleaved from an inactive precursor by a cysteinyl aspartate-specific protease (caspase)-1. this study aimed to test the hypothesis that inhibition in brain of the cleavage of biologically active il-1beta will reduce in rats both spontaneous nr ... | 2006 | 16455762 |
| evoked response potential markers for anesthetic and behavioral states. | the rodent whisker sensory system is a commonly used model of cortical processing; however, anesthetics cause profound differences in the shape and timing of evoked responses. evoked response studies, especially those that use spatial mapping techniques, such as fmri or optical imaging, will thus show significantly different results depending on the anesthesia used. to describe the effect of behavioral states and commonly used anesthetics, we characterized the early surface-evoked response poten ... | 2006 | 16455771 |
| effects of selective dopamine d4 receptor antagonist, l-741,741, on sleep and wakefulness in the rat. | the influence of the dopamine system upon sleep/wake states is not fully understood. to date, the role of dopamine d4 receptor has not been studied. the aim of this work is to study the influence of dopamine d4 receptor upon sleep/wake states in male rats. male wistar rats were implanted with electroencephalography and electromyography electrodes for sleep recording. sleep/wake times were compared in rats first treated with control solution (vehicle) and the day after treated with a potent and h ... | 2006 | 16457926 |
| cold exposure and sleep in the rat: effects on sleep architecture and the electroencephalogram. | acute exposure to low ambient temperature modifies the wake-sleep cycle due to stage-dependent changes in the capacity to regulate body temperature. this study was carried out to make a systematic analysis of sleep parameters during the exposure to different low ambient temperatures and during the following recoveries at ambient temperature 24 degrees c. | 2005 | 16477956 |
| inhibition of serotonergic medullary raphe obscurus neurons suppresses genioglossus and diaphragm activities in anesthetized but not conscious rats. | although exogenous serotonin at the hypoglossal motor nucleus (hmn) activates the genioglossus muscle, endogenous serotonin plays a minimal role in modulating genioglossus activity in awake and sleeping rats (sood s, morrison jl, liu h, and horner rl. am j respir crit care med 172: 1338-1347, 2005). this result therefore implies that medullary raphe neurons also play a minimal role in the normal physiological control of the hmn, but this has not yet been established because raphe neurons release ... | 2006 | 16484356 |
| sleep induction and temperature lowering by medial preoptic alpha(1) adrenergic receptors. | changes in sleep-wakefulness (s-w) and body temperature (t(b)) on administration of alpha(1) agonist (methoxamine) and antagonist (prazosin) into the medial preoptic area (mpoa) were studied in rats. presynaptic catecholaminergic terminals of the mpoa were destroyed by injecting 6-hydroxydopamine at the ventral noradrenergic bundle (vna), before administration of the drugs. microinjection of 0.05 microg methoxamine induced sleep, though 0.1 microg prazosin produced no change in s-w. on the other ... | 2006 | 16529782 |
| gaba(a) receptor modulation of 5-ht neuronal firing in the median raphe nucleus: implications for the action of anxiolytics. | 5-ht neurones in the median raphe nucleus (mrn) are involved in anxiety and the sleep/wake cycle. here, using in vitro electrophysiology, we examined if the firing of mrn 5-ht neurones is regulated by gaba(a) receptors. the gaba(a) receptor agonists thip and muscimol caused concentration dependent inhibition of mrn 5-ht neurones. the gaba(a) receptor antagonist bicuculline blocked the responses to thip and muscimol. bicuculline alone increased the basal firing activity. responses to thip were en ... | 2006 | 16531019 |
| tonic activity of alpha1 adrenergic receptors of the medial preoptic area contributes towards increased sleep in rats. | several studies have suggested that noradrenergic afferents to the medial preoptic area might be involved in hypnogenesis and in lowering the body temperature, and that the alpha1 adrenergic receptors might be mediating these responses. this study was undertaken to find out the changes in sleep-wakefulness and body temperature in rats, when these adrenergic receptors of the medial preoptic area are blocked by alpha1 selective antagonist, prazosin. adult male wistar rats were chronically implante ... | 2006 | 16533567 |
| adenosine inhibits basal forebrain cholinergic and noncholinergic neurons in vitro. | adenosine has been proposed as a homeostatic "sleep factor" that promotes the transition from waking to sleep by affecting several sleep-wake regulatory systems. in the basal forebrain, adenosine accumulates during wakefulness and, when locally applied, suppresses neuronal activity and promotes sleep. however, the neuronal phenotype mediating these effects is unknown. we used whole-cell patch-clamp recordings in in vitro rat brain slices to investigate the effect of adenosine on identified choli ... | 2006 | 16542780 |
| amyloid beta peptide (25-35) activates protein kinase c leading to cyclooxygenase-2 induction and prostaglandin e2 release in primary midbrain astrocytes. | prostaglandins (pgs) are generated by the enzymatic activity of cyclooxygenase-1 and -2 (cox-1/2) and modulate several functions in the cns such as the generation of fever, the sleep/wake cycle, and the perception of pain. moreover, the induction of cox-2 and the generation of pgs has been linked to neuroinflammatory aspects of alzheimer's disease (ad). non-steroidal anti-inflammatory drugs (nsaids) that block cox enzymatic activity have been shown to reduce the incidence of ad in various epidem ... | 2006 | 16546299 |
| modulation of somatosensory evoked potentials during wake-sleep states and spike-wave discharges in the rat. | to clarify the cortical evoked responses in the primary somatosensory cortex of the rat under states of waking, slow-wave sleep (sws), paradoxical sleep (ps), and spike-wave discharges (swds), which are associated with absence seizure. | 2006 | 16553013 |
| the preoptic hypothalamus and basal forebrain play opposing roles in the descending modulation of sleep and wakefulness in infant rats. | recent findings in infant rats suggest that the preoptic area (poa) and/or basal forebrain (bf) contribute to developmental changes in sleep and wake organization between postnatal day 2 (p2) and p9. to examine the contributions of these forebrain areas to sleep and wakefulness, separate lesions of the poa or bf, or combined lesions (poa + bf), were performed at p9, and precollicular transections were performed at p2. in addition, modafinil, a drug of unknown mechanism of action the effects of w ... | 2006 | 16553791 |
| orexins, energy balance, temperature, sleep-wake cycle. | | 2006 | 16556904 |
| electrophysiological diversity of the dorsal raphe cells across the sleep-wake cycle of the rat. | through their widespread projections to the entire brain, dorsal raphe cells participate in many physiological functions and are associated with neuropsychiatric disorders. in previous studies, the width of action potentials was used as a criterion to identify putative serotonergic neurons, and to demonstrate that cells with broad spikes were more active in wakefulness, slowed down their activity in slow wave sleep and became virtually silent during paradoxical sleep. however, recent studies rep ... | 2006 | 16613874 |
| role of noradrenergic and gaba-ergic inputs in pedunculopontine tegmentum for regulation of rapid eye movement sleep in rats. | rapid eye movement (rem) sleep disturbance is associated with several psycho-behavioral disorders, hence, it is important to understand its neural mechanism of regulation. although it was known that the noradrenergic (na-ergic) neurons from locus coeruleus (lc) project to the pedunculopontine tegmentum (ppt), the role of noradrenaline (na) alone and in association with gaba, an inhibitory neurotransmitter, in ppt for rem sleep regulation was not known and was investigated in this study in freely ... | 2006 | 16616214 |
| corticothalamic 5-9 hz oscillations are more pro-epileptogenic than sleep spindles in rats. | absence-related spike-and-wave discharges (swds) occur in the thalamocortical system during quiet wakefulness or drowsiness. in feline generalized penicillin epilepsy, swds develop from sleep spindles. in contrast, in genetic absence epilepsy rats from strasbourg (gaers), swds develop from wake-related 5-9 hz oscillations, which are distinct from spindle oscillations (7-15 hz). since these two oscillation types share common frequency bands and may contribute to swd genesis, it is important to co ... | 2006 | 16627566 |
| ghrelin-induced sleep responses in ad libitum fed and food-restricted rats. | ghrelin is an endogenous ligand for the growth hormone secretagogue receptor and a well-characterized food intake regulatory peptide. hypothalamic ghrelin-, neuropeptide y (npy)-, and orexin-containing neurons form a feeding regulatory circuit. orexins and npy are also implicated in sleep-wake regulation. sleep responses and motor activity after central administration of 0.2, 1, or 5 microg ghrelin in free-feeding rats as well as in feeding-restricted rats (1 microg dose) were determined. food a ... | 2006 | 16631138 |
| a systematic review of modafinil: potential clinical uses and mechanisms of action. | modafinil is a novel wake-promoting agent that has u.s. food and drug administration approval for narcolepsy and shift work sleep disorder and as adjunctive treatment of obstructive sleep apnea/hypopnea syndrome. modafinil has a novel mechanism and is theorized to work in a localized manner, utilizing hypocretin, histamine, epinephrine, gamma-aminobutyric acid, and glutamate. it is a well-tolerated medication with low propensity for abuse and is frequently used for off-label indications. the obj ... | 2006 | 16669720 |
| prenatal ethanol exposure alters the expression of period genes governing the circadian function of beta-endorphin neurons in the hypothalamus. | sleep-wake disturbances and stress hyper-responsiveness have been observed in human neonates, children and adolescents who were exposed to alcohol during the prenatal period. using the laboratory rat as an animal model, we investigated whether fetal ethanol exposure during gestational days 10-21 affects the circadian function of the stress-axis regulatory beta-endorphin neurons in the hypothalamus. fetal ethanol-exposed rats showed abnormality in the circadian expression of proopiomelanocortin ( ... | 2006 | 16686691 |
| serotonin turnover in different duration of sleep recovery in discrete regions of young rat brain after 24 h rem sleep deprivation. | sleep plays an important role in restorative function and serotonin (5-hydroxytryptamine: 5ht) equally plays important roles in sleep. though various studies have revealed the roles of 5ht in sleep/wake cycle, the mechanism involved is yet unclear. in the present study we investigated alteration of the 5ht turnover in various regions of the young rat brains after 24 hours (h) rem sleep (srem) deprivation to elucidate the roles of 5ht in sleep restoration function in the these regions. the 5ht tu ... | 2006 | 16697543 |
| [analysis of rat 24h heart rate variability based on telemetry technology]. | in this study ecg signal of unstrained rat was recorded by telemetry device, and heart rate variability (hrv) was analyzed in order to evaluate 24h autonomic nervous activity. the results demonstrated an obvious circadian rhythm in the autonomic nervous activity: sympathetic activity being dominant during wake phase, and parasympathetic activity, dominant during sleep phase. the ratio of the low frequency to high frequency components in hrv power spectrum (lf/hf) fluctuates with the change in th ... | 2006 | 16706337 |
| the orexin system regulates alcohol-seeking in rats. | 1. orexin-containing neurons have been implicated in feeding, sleep-wake cycles and more recently in drug-seeking behaviour. 2. pretreatment of alcohol-preferring (ip) rats with an orexin1 receptor antagonist (sb-334867, 20 mg kg(-1), intraperitoneally) completely abolished an olfactory cue-induced reinstatement of alcohol-seeking behaviour, and also attenuated alcohol responding under an operant fixed ratio regimen without affecting water responding. 3. the mrna encoding orexin within the hypot ... | 2006 | 16751790 |
| alpha-2 adrenergic regulation of pedunculopontine nucleus neurons during development. | rapid eye movement sleep decreases between 10 and 30 days postnatally in the rat. the pedunculopontine nucleus is known to modulate waking and rapid eye movement sleep, and pedunculopontine nucleus neurons are thought to be hyperpolarized by noradrenergic input from the locus coeruleus. the goal of the study was to investigate the possibility that a change in alpha-2 adrenergic inhibition of pedunculopontine nucleus cells during this period could explain at least part of the developmental decrea ... | 2006 | 16753270 |
| p-cpa pretreatment reverses the changes in sleep and behavior following acute immobilization stress rats. | the effects of p-cpa (para-chlorophenylalanine) pretreatment was studied on the sleep-wake parameters and patterns of behavioral activities in an animal model of acute immobilization stress. for the experiments, young male charles foster rats were divided into three groups, subjected to (i) acute immobilization stress for four hours on specially designed wooden boards, (ii) a similar model of acute immobilization stress after pretreatment of p-cpa (injected through i.p. route), and (iii) control ... | 2006 | 16779920 |
| obestatin alters sleep in rats. | obestatin is a recently identified peptide derived from the ghrelin gene. ghrelin stimulates food intake whereas obestatin has an opposite effect in rats. previous experiments in our laboratory revealed that ghrelin also induces wakefulness in rats. the aim of the present experiments was to study the effect of obestatin on sleep. rats received intraperitoneal (n = 7; 16 or 64 microg/kg) or intracerebroventricular (i.c.v.; n = 11) injection of pyrogen-free isotonic nacl or obestatin (1, 4 and 16 ... | 2006 | 16806691 |
| hippocampal synaptic plasticity and spatial learning are impaired in a rat model of sleep fragmentation. | sleep fragmentation, a symptom in many clinical disorders, leads to cognitive impairments. to investigate the mechanisms by which sleep fragmentation results in memory impairments, rats were awakened once every 2 min via 30 s of slow movement on an automated treadmill. within 1 h of this sleep interruption (si) schedule, rats began to sleep in the 90-s periods without treadmill movement. total non-rapid eye movement sleep (nrem) sleep time did not change over the 24 h of si, although there was a ... | 2006 | 16817877 |
| prenatal malnutrition and sleep states in adult rats: effects of restraint stress. | independently, prenatal malnutrition and psychological/physical stress have been shown to affect sleep architecture in adult rats. as malnutrition and stress commonly co-exist in malnourished human populations, the objective of the present study was to ascertain the combined effects of these two insults by examining sleep-wake parameters following a brief restraint stress in prenatally protein malnourished rats. the male offspring of rats provided with a protein deficient diet (6% casein) for 5 ... | 2006 | 16828813 |
| the sleep-enhancing effect of valerian inhalation and sleep-shortening effect of lemon inhalation. | we examined the effects of odorant inhalation on the sleep-wake states in rats. odorants used in the experiment were clove, jasmine, lavender, lemon, peppermint, pine, rose, sandalwood, valerian, and ylang-ylang. valerian and rose inhalation significantly prolonged the pentobarbital-induced sleeping time, whereas lemon inhalation significantly shortened it. the effect of valerian inhalation was markedly noticeable. in the anosmic rats, a significant effect of odorants on the pentobarbital sleep ... | 2006 | 16857858 |
| cholinergic regulation of the posterior medial thalamic nucleus. | we previously showed that the gabaergic nucleus zona incerta (zi) suppresses vibrissae-evoked responses in the posterior medial (pom) thalamus of the rodent somatosensory system. we proposed that this inhibitory incertothalamic pathway regulates pom responses during different behavioral states. here we tested the hypothesis that this pathway is modulated by the ascending brain stem cholinergic system, which regulates sleep-wake cycles and states of vigilance. we demonstrate that cholinergic inpu ... | 2006 | 16870838 |
| serotonin and 5-hydroxy-indole-acetic acid contents in dorsal raphe and suprachiasmatic nuclei in normal, malnourished and rehabilitated rats under 24 h of sleep deprivation. | it has been discussed that serotonin (5-ht) could be involved in the effects of sleep deprivation (sd) and/or malnutrition (m) on the sleep-wake cycle. the aim of this work was to study the effects of the m, sd and its interaction on 5-ht and 5-hydroxy-indole-acetic acid (5-hiaa) contents in the dorsal raphe (dr) and the suprachiasmatic nuclei (scn), two sleep-wake cycle regulators. forty-eight puppets rats were obtained from mothers fed with low or normal casein diet. they were allocated in 3 g ... | 2006 | 16876773 |
| evaluation of the effect of chronic exposure to 137cesium on sleep-wake cycle in rats. | since the chernobyl accident, the most significant problem for the population living in the contaminated areas is chronic exposure by ingestion of radionuclides, notably (137)cs, a radioactive isotope of cesium. it can be found in the whole body, including the central nervous system. the present study aimed to assess the effect of (137)cs on the central nervous system and notably on open-field activity and the electroencephalographic pattern. rats were exposed up to 90 days to drinking water con ... | 2006 | 16876929 |
| adenosine and sleep homeostasis in the basal forebrain. | it is currently hypothesized that the drive to sleep is determined by the activity of the basal forebrain (bf) cholinergic neurons, which release adenosine (ad), perhaps because of increased metabolic activity associated with the neuronal discharge during waking, and the accumulating ad begins to inhibit these neurons so that sleep-active neurons can become active. this hypothesis grew from the observation that ad induces sleep and ad levels increase with wake in the basal forebrain, but surpris ... | 2006 | 16885223 |
| sleep-wake study in an animal model of acute and chronic heat stress. | the study of the variations in different parameters of sleep-wake states following exposure to high environmental heat in three different age groups of freely moving rats have been presented in this paper. each age group of rats was subdivided in three group (i) acute heat stress--subjected to a single exposure for 4 h in the bod (biological oxygen demand) incubator at 38 degrees c; (ii) chronic heat stress--exposed for 21 days daily for 1 h in the incubator at 38 degrees c, and (iii) handling c ... | 2006 | 16899261 |
| central administration of neuropeptide y induces wakefulness in rats. | neuropeptide y (npy) is a well-characterized neuromodulator in the central nervous system, primarily implicated in the regulation of feeding. npy, orexins, and ghrelin form a hypothalamic food intake regulatory circuit. orexin and ghrelin are also implicated in sleep-wake regulation. in the present experiments, we studied the sleep-modulating effects of central administration of npy in rats. rats received intracerebroventricular injection of physiological saline or three different doses of npy ( ... | 2006 | 16914434 |
| sleep and brain monoamine changes produced by acute and chronic acetaldehyde administration in rats. | acetaldehyde, the most toxic metabolite of ethanol, has been implicated in many toxic effects of ethanol. in the present study, we used rats to investigate the possible changes on the sleep-wake cycle and brain regional concentrations of noradrenaline and serotonin after intraperitoneal administration of several doses of acetaldehyde. results showed that acetaldehyde significantly decreases the time spent in rapid eye movements sleep and wakefulness and increases the time spent in slow-wave slee ... | 2006 | 16920203 |
| fast modulation of prefrontal cortex activity by basal forebrain noncholinergic neuronal ensembles. | traditionally, most basal forebrain (bf) functions have been attributed to its cholinergic neurons. however, the majority of cortical-projecting bf neurons are noncholinergic and their in vivo functions remain unclear. we investigated how bf modulates cortical dynamics by simultaneously recording </=50 bf single neurons along with local field potentials (lfps) from the prefrontal cortex (pfcx) in different wake-sleep states of adult rats. using stereotypical spike time correlations, we identifie ... | 2006 | 16928796 |
| csf orexin a concentrations and expressions of the orexin-1 receptor in rat hippocampus after cardiac arrest. | orexins/hypocretins are neuropeptides that have various physiological effects, including the regulation of feeding behavior, neuroendocrine functions and sleep-wake cycles. recent studies have suggested that the orexin system may also be involved in brain ischemic reactions. it is also known that changes in sleep patterns, energy homeostasis and neuroendocrine functions are often occur in neurological conditions associated brain ischemia. in the current study, we investigated the time-dependent ... | 2006 | 16930690 |
| endogenous excitatory drive modulating respiratory muscle activity across sleep-wake states. | the concept of a tonic drive activating respiratory muscle in wakefulness but not sleep has been an important and enduring notion in respiratory medicine, not least because it is useful in modeling sleep effects on breathing and understanding the pathogenesis of sleep-related breathing disorders such as obstructive sleep apnea. however, a neurotransmitter substrate mediating respiratory muscle activation across sleep-wake states has not been identified. | 2006 | 16931636 |
| firing properties of anatomically identified neurons in the medial septum of anesthetized and unanesthetized restrained rats. | cholinergic and gabaergic neurons in the medial septum-diagonal band of broca (ms-db) project to the hippocampus where they are involved in generating theta rhythmicity. so far, the functional properties of neurochemically identified ms-db neurons are not fully characterized. in this study, ms-db neurons recorded in urethane anesthetized rats and in unanesthetized restrained rats were labeled with neurobiotin and processed for immunohistochemistry against glutamic acid decarboxylase (gad), parva ... | 2006 | 16943562 |
| ghrelin and sleep-wake regulation. | | 2007 | 16946077 |
| memory-based detection of rare sound feature combinations in anesthetized rats. | it is unclear whether the ability of the brain to discriminate rare from frequently repeated combinations of sound features is limited to the normal sleep/wake cycle. we recorded epidural auditory event-related potentials in urethane-anesthetized rats presented with rare tones ('deviants') interspersed with frequently repeated ones ('standards'). deviants differed from standards either in frequency alone or in frequency combined with intensity. in both cases, deviants elicited event-related pote ... | 2006 | 16957608 |
| p2y receptor-mediated excitation in the posterior hypothalamus. | histaminergic neurons located in the posterior hypothalamus (tuberomamillary nucleus, tmn) project widely through the whole brain controlling arousal and attention. they are tonically active during wakefulness but cease firing during sleep. as a homeostatic theory of sleep involves atp depletion and adenosine accumulation in the brain, we investigated the role of atp and its analogues as well as adenosine on neuronal activity in the tmn. we show increased firing of rat tmn neurons by atp, adp, u ... | 2006 | 16965543 |
| homeostatic regulation of sleep: a role for preoptic area neurons. | the median preoptic nucleus (mnpn) and the ventrolateral preoptic area (vlpoa) contain putative sleep-regulatory neurons that exhibit elevated discharge rates during sleep compared with waking. expression of c-fos protein immunoreactivity (ir) in gabaergic neurons in the mnpn and the vlpoa is high in spontaneously sleeping rats and in rats undergoing recovery sleep after sleep deprivation. however, it is unclear whether c-fos-ir in these neurons is evoked by increases in sleep pressure or by inc ... | 2006 | 16971526 |
| inducible and neuronal nitric oxide synthases (nos) have complementary roles in recovery sleep induction. | sleep homeostasis is the process by which recovery sleep is generated by prolonged wakefulness. the molecular mechanisms underlying this important phenomenon are poorly understood. we have previously shown that nitric oxide (no) generation increases in the basal forebrain (bf) during sleep deprivation (sd). moreover, both no synthase (nos) inhibition and a no scavenger prevented recovery sleep induction, while administration of a no donor during the spontaneous sleep-wake cycle increased sleep, ... | 2006 | 16987226 |
| monoaminergic system lesions increase post-sigh respiratory pattern disturbance during sleep in rats. | monoamines are important regulators of behavioral state and respiratory pattern, and the impact of monoaminergic control during sleep is of particular interest for the stability of breathing regulation. the aim of this study was to test the effects of systemically induced chemical lesions to noradrenergic and serotonergic efferent systems, on the expression of sleep-wake states, pontine wave activity, and sleep-related respiratory pattern and its variability. in chronically instrumented male adu ... | 2007 | 16989875 |
| innervation of orexin/hypocretin neurons by gabaergic, glutamatergic or cholinergic basal forebrain terminals evidenced by immunostaining for presynaptic vesicular transporter and postsynaptic scaffolding proteins. | orexin/hypocretin (orx) neurons are critical for the maintenance of waking in association with behavioral arousal and postural muscle tone, since with their loss narcolepsy with cataplexy occurs. given that basal forebrain (bf) neurons project to the hypothalamus and play important diverse roles in sleep/wake states, we sought to determine whether acetylcholine (ach), glutamate (glu), and/or gaba-releasing bf neurons innervate and could thereby differentially regulate the orx neurons. from discr ... | 2006 | 17029265 |
| circadian regulation of arousal: role of the noradrenergic locus coeruleus system and light exposure. | noradrenergic locus coeruleus (lc) neurons regulate arousal. previous studies have shown that noradrenergic lc neurons exhibit a circadian rhythm in impulse activity, which peaks during the active period. this is mediated by an indirect circuit projection from the suprachiasmatic nucleus (scn) to the lc. here we sought to evaluate the hypothesis that the lc regulates the circadian properties of the sleep-wake cycle. | 2006 | 17068987 |
| sleep, temperature, activity, and prolactin phenotypes of genetically epilepsy-prone rats. | sleep-wake disturbances are common in epilepsy, yet the potential adverse effect of seizures on sleep is not well characterized. genetically epilepsy-prone rats (geprs) are a well-studied model of genetic susceptibility to audiogenic seizures. to assess their suitability for investigating relationships between seizures and disordered sleep, we characterized the sleep, activity, and tempera ture patterns of 2 gepr strains (designated 3 and 9) and sprague-dawley (sd) rats in the basal state, after ... | 2006 | 17069025 |
| effect of the beta3 adrenoceptor agonist cl 316243 on hypothalamic 5-ht synthesis and suppression of rem sleep in the rat. | beta3 adrenoceptor agonists show an antidepressant-like profile in preclinical rodent assays and improve mood in clinically-obese patients. these observations suggest a possible antidepressant utility for beta3 adrenoceptor agonists. the present study examined the effects of acute and chronic administration of the beta3 adrenoceptor agonist cl 316243 on two physiological indicators of antidepressant activity in the rat: hypothalamic 5-ht synthesis and suppression of rem sleep. 5-ht synthesis was ... | 2007 | 17092981 |
| lipocalin-type prostaglandin d synthase produces prostaglandin d2 involved in regulation of physiological sleep. | prostaglandin (pg) d2 has been proposed to be essential for the initiation and maintenance of the physiological sleep of rats because intracerebroventricular administration of selenium tetrachloride (secl4), a selective inhibitor of pgd synthase (pgds), was shown to reduce promptly and effectively the amounts of sleep during the period of infusion. however, gene knockout (ko) mice of pgds and prostaglandin d receptor (dp1r) showed essentially the same circadian profiles and daily amounts of slee ... | 2006 | 17093043 |
| relationship between the perifornical hypothalamic area and oral pontine reticular nucleus in the rat. possible implication of the hypocretinergic projection in the control of rapid eye movement sleep. | the perifornical (pef) area in the posterior lateral hypothalamus has been implicated in several physiological functions including the regulation of sleep-wakefulness. some pef neurons, which contain hypocretin, have been suggested to play an important role in sleep-wake regulation. the aim of the present study was to examine the effect of the pef area and hypocretin on the electrophysiological activity of neurons of the oral pontine reticular nucleus (pno), which is an important structure in th ... | 2006 | 17116163 |
| impact of proestrous milieu on expression of orexin receptors and prepro-orexin in rat hypothalamus and hypophysis: actions of cetrorelix and nembutal. | orexins and their receptors ox1 and ox2 regulate energy balance and the sleep-wake cycle. we studied the expression of prepro-orexin (ppo), ox1, and ox2 in brain and pituitary under the influence of the hormonal status in adult rats. primarily, ppo, ox1, and ox2 expression was determined in sprague-dawley female cycling rats during proestrus and in males. animals were killed at 2-h intervals. anterior (ah) and mediobasal (mbh) hypothalamus, anterior pituitary (p), and frontoparietal cortex (cc) ... | 2007 | 17122088 |
| sedative and hypnotic activities of the ethanol fraction from fructus schisandrae in mice and rats. | fruits of fructus schisandrae have been used as medicine for the treatment for insomnia in traditional chinese medicine. in the present research, the sedative and hypnotic activities of the ethanol fraction of fructus schisandrae fruit (sy3) were studied in mice and rats. in the open field test, sy3 (25, 50 and 100 mg/kg) significantly inhibited the motor activity of mice compared to the normal. results also showed sy3 potentiated pentobarbital-induced sleep by not only increasing the number of ... | 2007 | 17127021 |
| armodafinil, the r-enantiomer of modafinil: wake-promoting effects and pharmacokinetic profile in the rat. | modafinil reduces the excessive sleepiness associated with narcolepsy, obstructive sleep apnea/hypopnea syndrome, and shift work sleep disorder. in rats, modafinil promotes dose-dependent increases in wake duration. the wake-promoting activity of the r-enantiomer of modafinil (armodafinil) was evaluated in wky rats and compared to the classical stimulant, d-methamphetamine. electroencephalographic and electromyographic signals were assessed via a tethered cranial implant. body temperature and lo ... | 2006 | 17134745 |
| distinct patterns of striatal medium spiny neuron activity during the natural sleep-wake cycle. | striatal medium-sized spiny neurons (msns) integrate and convey information from the cerebral cortex to the output nuclei of the basal ganglia. intracellular recordings from anesthetized animals show that msns undergo spontaneous transitions between hyperpolarized and depolarized states. state transitions, regarded as necessary for eliciting action potential firing in msns, are thought to control basal ganglia function by shaping striatal output. here, we use an anesthetic-free rat preparation t ... | 2006 | 17135420 |
| prominent burst firing of dopaminergic neurons in the ventral tegmental area during paradoxical sleep. | dopamine is involved in motivation, memory, and reward processing. however, it is not clear whether the activity of dopamine neurons is related or not to vigilance states. using unit recordings in unanesthetized head restrained rats we measured the firing pattern of dopamine neurons of the ventral tegmental area across the sleep-wake cycle. we found these cells were activated during paradoxical sleep (ps) via a clear switch to a prominent bursting pattern, which is known to induce large synaptic ... | 2007 | 17151599 |
| gamma-aminobutyric acid (gaba) receptor mediates suanzaorentang, a traditional chinese herb remedy, -induced sleep alteration. | the sedative-hypnotic medications, including benzodiazepines and non-benzodiazepines, are the most common treatments for insomnia. however, concerns regarding patterns of inappropriate use, dependence and adverse effects have led to caution in prescribing those sedative-hypnotic medications. on the other hand, a traditional chinese herb remedy, suanzaorentang, has been efficiently and widely used in clinic for insomnia relief without severe side effects in asia. although suanzaorentang has been ... | 2007 | 17151826 |
| midfrequency cortico-thalamic oscillations and the sleep cycle: genetic, time of day and age effects. | wag/rij rats have various types of mid frequency cortico-thalamic oscillations, such as anterior and posterior sleep spindles and two types of spike-wave discharges (swd). the generalized swd (type i) preferentially occur at transitions from wake to sleep, type ii can be found at the occipital cortex during quite wakefulness. in the present experiment sleep spindles, swd and sleep cycle characteristics of 6-month-old wag/rij rats were studied and compared with those of younger wag/rij rats with ... | 2007 | 17156975 |
| mesopontine cholinergic projections to the hypoglossal motor nucleus. | mesopontine cholinergic (ach) neurons have increased discharge during wakefulness, rapid eye movement (rem) sleep, or both. hypoglossal (12) motoneurons, which play an important role in the control of upper airway patency, are postsynaptically excited by stimulation of nicotinic receptors, whereas muscarinic receptors presynaptically inhibit inputs to 12 motoneurons. these data suggest that ach contributes to sleep/wake-related changes in the activity of 12 motoneurons by acting within the hypog ... | 2007 | 17174027 |
| changes in extracellular glutamate levels in rat orbitofrontal cortex during sleep and wakefulness. | functional neuroimaging studies have shown that limbic and paralimbic areas display increased activity during rem sleep when compared to wakefulness. this increase in limbic activity is specific to the rem period of sleep. pet scanners do not provide a neurochemical explanation for this increased activity during rem sleep. in order to better understand the neurochemical basis of this increase, extracellular glutamate levels were measured in the rat orbitofrontal cortex during the stages of sleep ... | 2007 | 17174723 |
| extra-auditory effects of noise in laboratory animals: the relationship between noise and sleep. | noise has both auditory and extra-auditory effects. some of the most deleterious extra-auditory effects of noise are those leading to sleep disturbances. these disturbances seem to be related to both endogenous (physical parameters) and exogenous (sex, age) factors of noise. despite correlative relations between noise level and awakenings, the scientific community has not reached consensus regarding a specific action of these factors on the different sleep stages. in animal research, 2 complemen ... | 2007 | 17203914 |
| evidence for electrical coupling in the subcoeruleus (subc) nucleus. | subcoeruleus (subc) neurons, which are thought to modulate rapid-eye-movement (rem) sleep, were recorded in brain stem slices from 7- to 20-day rats and found to manifest spikelets, indicative of electrical coupling. spikelets occurred spontaneously or could be induced by superfusion of the cholinergic agonist carbachol. whole cell recordings revealed that carbachol induced membrane oscillations and spikelets in the theta frequency range in subc neurons in the presence of fast synaptic blockers. ... | 2007 | 17215497 |
| effects of serotonin on perifornical-lateral hypothalamic area neurons in rat. | the hypocretin (hcrt) system of the perifornical-lateral hypothalamic area (pf-lha) has been implicated in the facilitation of behavioral arousal. hcrt neurons receive serotonergic afferents from the dorsal raphe nucleus. although in-vitro pharmacological studies suggest that serotonin (5-ht) inhibits hcrt neurons, the in-vivo effects of 5-ht on hcrt neurons in the pf-lha and associated behavioral changes have not been described. we examined the effects of 5-ht delivered locally into the pf-lha ... | 2007 | 17241281 |
| [orexinergic neurons and noradrenergic awakening system in general anesthesia]. | the sleep-wake cycle is regulated by interaction between monoaminergic, cholinergic and gabaergic neuronal activities. monoaminergic neurons including noradrenergic (locus coeruleus: lc), histaminergic (tuberomammillary nucleus) and serotonergic (raphe nuclei) neurons projected diffusely to the cerebrocortex, thalamus and brainstem are known as the center of sleep regulation. interestingly, although the cell bodies displaying prepro-orexin (prepro-ox) immunoreactivity are limited to the hypothal ... | 2007 | 17243641 |
| [orexins and pain processing]. | orexin-a and orexin-b are hypothalamic peptides and regulate feeding behavior, energy metabolism and the sleep-wake cycle. orexin-a binds equally to both orexin-1 and orexin-2 receptors, while orexin-b has a preferential affinity for orexin-2 receptors. orexin-a and orexin-b are concentrated in superficial laminae of the spinal dorsal horn, and orexin-a and orexin-1 receptors are found in the dorsal root ganglion cells. intravenous injection of orexin-a produces an anti-thermal hyperalgesic effe ... | 2007 | 17243644 |
| promotion of sleep by targeting the orexin system in rats, dogs and humans. | orexins are hypothalamic peptides that play an important role in maintaining wakefulness in mammals. permanent deficit in orexinergic function is a pathophysiological hallmark of rodent, canine and human narcolepsy. here we report that in rats, dogs and humans, somnolence is induced by pharmacological blockade of both orexin ox(1) and ox(2) receptors. when administered orally during the active period of the circadian cycle, a dual antagonist increased, in rats, electrophysiological indices of bo ... | 2007 | 17259994 |
| effect of valerian extract preparation (bim) on the sleep-wake cycle in rats. | in the present study, we studied the effect of valerian extract preparation (bim) containing valerian extract, golden root (rhodiola rosea l.) extract and l-theanine (gamma-glutamylethylamide) on the sleep-wake cycle using sleep-disturbed model rats in comparison with that of valerian extract. a significant shortening in sleep latency was observed with valerian extract and the bim at a dose of 1000 mg/kg. on the other hand, valerian extract and the bim caused no significant effects on total time ... | 2007 | 17268081 |
| involvement of nitric oxide in cocaine-induced erections and ejaculations after paradoxical sleep deprivation. | as nitric oxide (no) is involved in penile erectile (pe) function and also influences the sleep-wake cycle, we speculated that no could play a role in pe and ejaculation of paradonical sleep deprivation (psd) rats. | 2007 | 17276569 |
| influence of time-varying magnetic field on the release of neurotransmitters in raphe nuclei of rats. | a specially-designed time-varying magnetic field was developed to treat insomnia. clinical results showed that this method could shorten the time to go to sleep and prolong the sleep duration. however, the mechanism of this method is still not well understood. in this study, the effect of magnetic stimulation on the release of serotonin (5-ht), noradrenaline (ne), dopamine (da) in raphe nuclei of rats, which are known to play an important role in the sleep-wake regulation, was investigated. it w ... | 2005 | 17281685 |
| developmental divergence of sleep-wake patterns in orexin knockout and wild-type mice. | narcolepsy, a disorder characterized by fragmented bouts of sleep and wakefulness during the day and night as well as cataplexy, has been linked in humans and nonhuman animals to the functional integrity of the orexinergic system. adult orexin knockout mice and dogs with a mutation of the orexin receptor exhibit symptoms that mirror those seen in narcoleptic humans. as with narcolepsy, infant sleep-wake cycles in humans and rats are highly fragmented, with consolidated bouts of sleep and wakeful ... | 2007 | 17284193 |
| propionate increases neuronal histone acetylation, but is metabolized oxidatively by glia. relevance for propionic acidemia. | in propionic acidemia, propionate acts as a metabolic toxin in liver cells by accumulating in mitochondria as propionyl-coa and its derivative, methylcitrate, two tricarboxylic acid cycle inhibitors. little is known about the cerebral metabolism of propionate, although clinical effects of propionic acidemia are largely neurological. we found that propionate was metabolized oxidatively by glia: [3-(14)c]propionate injected into mouse striatum or cortex, gave a specific activity of glutamine that ... | 2007 | 17286595 |
| effects of some h1-antagonists on the sleep-wake cycle in sleep-disturbed rats. | the present study was undertaken to investigate the effects of some h(1)-antagonists on the sleep-wake cycle in sleep-disturbed rats in comparison with those of nitrazepam. electrodes were chronically implanted into the frontal cortex and the dorsal neck muscle of rats for the electroencephalogram (eeg) and electromyogram (emg), respectively. eeg and emg were recorded with an electroencephalograph. sleepsign ver. 2.0 was used for eeg and emg analysis. the total times of waking, non-rapid eye mov ... | 2007 | 17287588 |
| the median preoptic nucleus reciprocally modulates activity of arousal-related and sleep-related neurons in the perifornical lateral hypothalamus. | the perifornical-lateral hypothalamic area (pf/lh) contains neuronal groups playing an important role in control of waking and sleep. among the brain regions that regulate behavioral states, one of the strongest sources of projections to the pf/lh is the median preoptic nucleus (mnpn) containing a sleep-active neuronal population. to evaluate the role of mnpn afferents in the control of pf/lh neuronal activity, we studied the responses of pf/lh cells to electrical stimulation or local chemical m ... | 2007 | 17301170 |
| genioglossus muscle activity and serotonergic modulation of hypoglossal motor output in obese zucker rats. | obese zucker rats have a narrower and more collapsible upper airway compared with lean controls, similar to obstructive sleep apnea (osa) patients. genioglossus (gg) muscle activity is augmented in awake osa patients to compensate for airway narrowing, but the neural control of gg activity in obese zucker rats has not been investigated to determine whether such neuromuscular compensation also occurs. this study tests the hypotheses that gg activity is augmented in obese zucker rats compared with ... | 2007 | 17332267 |
| effects of the fatty acid amide hydrolase inhibitor urb597 on the sleep-wake cycle, c-fos expression and dopamine levels of the rat. | our group has described previously that the endogenous cannabinoid anandamide induces sleep. the hydrolysis of this lipid involves the activity of the fatty acid amide hydrolase (faah), which additionally catalyzes the degradation of the satiety factor oleoylethanolamide and the analgesic-inducing lipid palmitoylethanolamide. it has been demonstrated that the inhibition of the faah by urb597 increases levels of anandamide, oleoylethanolamide and palmitoylethanolamide in the brain of rats. in ord ... | 2007 | 17336288 |
| neural prosthesis in the wake of nanotechnology: controlled growth of neurons using surface nanostructures. | neural prosthesis has been successfully applied to patients with motional or sensory disabilities for clinical purpose. to enhance the performance of the neural prosthetic device, the electrodes for the biosignal recording or electrical stimulation should be located in closer proximity to target neurons than they are now. instead of revising the prior implanting surgery to improve the electrical contact of neurons, we propose a technique that can bring the neurons closer to the electrode sites. ... | 2006 | 17370781 |
| spontaneous sleep and homeostatic sleep regulation in ghrelin knockout mice. | ghrelin is well known for its feeding and growth hormone-releasing actions. it may also be involved in sleep regulation; intracerebroventricular administration and hypothalamic microinjections of ghrelin stimulate wakefulness in rats. hypothalamic ghrelin, together with neuropeptide y and orexin form a food intake-regulatory circuit. we hypothesized that this circuit also promotes arousal. to further investigate the role of ghrelin in the regulation of sleep-wakefulness, we characterized spontan ... | 2007 | 17409264 |
| effects of ageing on the fine distribution of the circadian clock protein in reticular formation neurons. | many biochemical, physiological and behavioural processes, from bacteria to human, exhibit roughly 24 h cyclic oscillations defined as circadian rhythms. however, during ageing, numerous aspects of the circadian biology undergo alterations; in particular, the sleep pattern changes, with more frequent awakenings and shorter sleep time. the basic mechanism of the circadian clock relies on intracellular molecular pathways involving interlocking transcriptional/translational feedback loops, and cloc ... | 2007 | 17415583 |
| hypoglycemia activates arousal-related neurons and increases wake time in adult rats. | hypoglycemia resulting from excess of exogenous or endogenous insulin elicits central nervous system activation that contributes to counterregulatory hormone secretion. in adult humans without diabetes, hypoglycemia occurring during sleep usually produces cortical activation with awakening. however, in adult humans with type 1 diabetes, hypoglycemic arousal appears blunted or absent. we hypothesized that insulin injection sufficient to produce hypoglycemia would induce awakening in adult male ra ... | 2007 | 17434543 |
| effect of basal forebrain neuropeptide y administration on sleep and spontaneous behavior in freely moving rats. | neuropeptide y (npy) is present both in local neurons as well as in fibers in the basal forebrain (bf), an area that plays an important role in the regulation of cortical activation. in our previous experiments in anaesthetized rats, significant eeg changes were found after npy injections to bf. eeg delta power increased while power in theta, alpha, and beta range decreased. the aim of the present experiments was to determine whether npy infusion to bf can modulate sleep and behavior in freely m ... | 2007 | 17452289 |
| effects of cox-2 inhibitor in temporomandibular joint acute inflammation. | since it is recognized that cyclo-oxygenase-2 mediates nociception and the sleep-wake cycle as well, and that acute inflammation of the temporomandibular joint (tmj) results in sleep disturbances, we hypothesized that cyclo-oxygenase-2 inhibitor would restore the sleep pattern in this inflammatory rat model. first, sleep was monitored after the injection of freund's adjuvant (fa group) or saline (sham group) into the rats' temporomandibular joint. second, etoricoxib was co-administered in these ... | 2007 | 17452571 |
| circadian desynchronization of core body temperature and sleep stages in the rat. | proper functioning of the human circadian timing system is crucial to physical and mental health. much of what we know about this system is based on experimental protocols that induce the desynchronization of behavioral and physiological rhythms within individual subjects, but the neural (or extraneural) substrates for such desynchronization are unknown. we have developed an animal model of human internal desynchrony in which rats are exposed to artificially short (22-h) light-dark cycles. under ... | 2007 | 17452631 |
| time- and dose-related effects of three 5-ht receptor ligands on the genioglossus activity in anesthetized and conscious rats. | clinical trials in obstructive sleep apnea syndrome patients reported moderate effects of serotoninergic drugs on oropharyngeal apneas, although numerous specific 5-ht ligands highly modulate the genioglossus muscle (gg) activity in experiments performed in anesthetized animals. the purpose of this study was to investigate time- and dose-related effects of central and systemic injections of 8-ohdpat (5-ht1a agonist), sb224289 (5-ht1b antagonist), and doi (5-ht2a/2c agonist) on the gg activity in ... | 2007 | 17457631 |
| central and baroreflex control of heart period during the wake-sleep cycle in spontaneously hypertensive rats. | we investigated whether the relative contribution of the baroreflex and central commands to the control of heart period differs between spontaneously hypertensive rats (shr) and wistar-kyoto normotensive rats (wky) during physiological behavior. rats were instrumented with an arterial catheter and with electrodes for discriminating wakefulness, nonrapid eye movement sleep (nrems), and rapid eye movement sleep (rems). the cross-correlation function (ccf) between spontaneous fluctuations of heart ... | 2007 | 17459912 |