| hazard assessment of boric acid in toys. | boric acid (h3bo3) has been used in a wide variety of applications--medication, pesticides, and household products. reports of child poisoning by h3bo3 were common in the clinical literature before 1975. however, a decline in its use as a bacteriostatic agent coupled with increased regulatory control has almost eliminated poisonings by accidental ingestion. schedule i (part i, item 8) of the hazardous products act of canada, proclaimed in the late 1960s, followed in the wake of concerns about ac ... | 1997 | 9441917 |
| activation of a distinct arousal state immediately after spontaneous awakening from sleep. | in contrast to the many neural studies into the mechanisms of sleep onset and maintenance, few studies have focused specifically on awakening from sleep. however, the abrupt electrographic changes and large brief cardio-respiratory activation at awakening suggest that a distinct, transiently aroused, awake state may exist compared to later wakefulness. to test this hypothesis we utilized the acoustic startle reflex, a standard un-conditioned reflex elicited by a sudden loud noise. this reflex is ... | 1997 | 9462884 |
| eeg power densities (0.5-20 hz) in different sleep-wake stages in rats. | frontofrontal and frontoparietal eeg power densities (0.5-20 hz) in waking, light and deep slow-wave sleep, transition-type sleep, and rapid-eye-movement (rem) sleep were investigated for 8 h during the light period in 16 male wistar rats. the data indicate that as delta activity (0.5-4.5 hz) increased from light to deep slow-wave sleep, the number of epochs per scoring epoch with high sigma activity (11-16 hz) as well as power densities in the rest of the spectrum (5-20 hz) including sigma freq ... | 1998 | 9469736 |
| on-line detection of extracellular levels of serotonin in dorsal raphe nucleus and frontal cortex over the sleep/wake cycle in the freely moving rat. | we used in vivo microdialysis coupled with polygraphic recording to monitor 5-hydroxytryptamine levels in the dorsal raphe nucleus and frontal cortex across waking, slow-wave sleep and rapid eye-movement sleep. male sprague-dawley rats were prepared with electroencephalogram and electromyogram electrodes. microdialysis probes were placed in dorsal raphe nucleus and/or frontal cortex. dialysate samples were manually collected during polygraphically-defined behavioural states and the level of sero ... | 1998 | 9483564 |
| effects of paradoxical sleep deprivation on thermoregulation in the rat. | rats were subjected to chronic paradoxical sleep deprivation (psd) by the disk-over-water method to determine if they would develop the sustained increase in core (hypothalamic) temperature (t(hy)); elevated temperature setpoint (tset); and the attenuation of the normal decline in core temperature during the transition from wake to sleep observed in rats subjected to total sleep deprivation (tsd). psd rats did not show a significant elevation in t(hy). psd rats and their yoked controls (psc) wer ... | 1998 | 9485528 |
| differential modulation of high-frequency gamma-electroencephalogram activity and sleep-wake state by noradrenaline and serotonin microinjections into the region of cholinergic basalis neurons. | several lines of evidence indicate that cholinergic basalis neurons play an important role in cortical activation. the present study was undertaken to determine the effect of noradrenergic and serotonergic modulation of the cholinergic neurons on cortical eeg activity and sleep-wake states. the neurotransmitters were injected into the region of the basalis neurons by remote control in freely moving, naturally sleeping-waking rats during the day when the rats are normally asleep the majority of t ... | 1998 | 9502823 |
| origin of the neurotensinergic innervation of the rat basal forebrain studied by retrograde transport of cholera toxin. | basal forebrain cholinergic neurons project to the hippocampus and cerebral cortex where they play an important role in cortical activation, attention, and memory. these neurons have been shown to express functional neurotensin receptors and to receive a dense neurotensinergic innervation. in the present study, we investigated the origin of this innervation by combining retrograde transport of cholera toxin with immunohistochemical detection of neurotensin. after injection of cholera toxin in th ... | 1998 | 9527539 |
| the effects of sensory stimulation on rem sleep duration. | previous experiments have demonstrated that auditory (as) and/or somatosensory (ss) stimulation can increase the duration of rem sleep periods in rats, cats and humans. the objectives of this study were to determine whether repeated as stimulation causes habituation to the stimulus and whether any additive effects could be obtained with the simultaneous application of as and ss. three experimental procedures were used in this study. in experiment 1, animals were recorded for 4 consecutive days w ... | 1998 | 9542797 |
| effects of temperature on sleep in the developing rat. | in altricial species, such as humans and rats, much of the development of autonomic systems occurs postnatally. consequently, vulnerabilities exist early in postnatal development when immature autonomic functions are challenged by external factors such as variations in ambient temperature (ta). ta profoundly influences sleep/wake state structure in adult animals and humans, and exposure to excessive warmth has been implicated as a risk factor in sudden infant death syndrome. to better understand ... | 1998 | 9575973 |
| blood glucose and ischemic brain damage. | the effect of hyperglycemia on ischemic brain damage was studied in a rat model of incomplete ischemia. incomplete ischemia was produced by permanent occlusion of one (either left or right) common carotid artery (cca). hyperglycemia was induced by intraperitoneal injection of 50% glucose, and same volume of physiological saline was injected in the controls 40 min before cca ligation. serum glucose level, at the time of vessel ligation, was 33.3 mmol/l. after cca ligation, the rats were allowed t ... | 1998 | 9581071 |
| effects of muscimol or homotaurine on sleep-wake states in alcohol-dependent rats during withdrawal. | sleep-wake states were studied following withdrawal in 36 adult male wistar alcohol-dependent rats, after chronic administration of ethanol (10 g/kg/24 h) for 13 days. in the light phase of the withdrawal day, 12 alcohol-dependent rats received muscimol (0.25 mg/kg), 12 received homotaurine (140 mg/kg), and 12 received 0.9% physiological saline (10 ml/kg). the results have been compared with a control group of 36 rats that received water during the treatment phase of the experiment, and the 14th ... | 1998 | 9586855 |
| altered neuronal activity rhythm and glutamate receptor expression in the suprachiasmatic nuclei of trypanosoma brucei-infected rats. | the parasites trypanosoma brucei cause african trypanosomiasis (sleeping sickness), a severe neuropsychiatric disease with marked disturbances of sleep-wake alternation. the sites of brain lesions are not well characterized. the present experimental investigation is focused on the hypothalamic suprachiasmatic nuclei, which play a role of a biological clock entraining endogenous rhythms in the mammalian brain. the electrophysiological properties of these neurons were analyzed in slice preparation ... | 1998 | 9600194 |
| cortical and thalamic visual evoked potentials during sleep-wake states and spike-wave discharges in the rat. | flash visual evoked potentials (vep) were simultaneously recorded from the primary visual cortex and the dorsal lateral geniculate nucleus in freely-moving wag/rij rats, to investigate whether the thalamic vep shows the same state-dependent alterations as the cortical vep. veps obtained during active and passive wakefulness (aw and pw), slow-wave sleep (sws), rem sleep and during the occurrence of spike-wave discharges (swd), a specific trait of the genetically epileptic wag/rij rat, were compar ... | 1998 | 9607520 |
| innervation of histaminergic tuberomammillary neurons by gabaergic and galaninergic neurons in the ventrolateral preoptic nucleus of the rat. | the tuberomammillary nucleus (tmn) is the major source of histaminergic innervation of the mammalian brain and is thought to play a major role in regulating wake-sleep states. we recently found that sleep-active neurons in the ventrolateral preoptic nucleus (vlpo) provide a major input to the tmn, but the specificity of this projection and the neurotransmitters involved remain unknown. in this study, we examined the relationship of vlpo efferents to the tmn using both retrograde and anterograde ... | 1998 | 9614245 |
| compensatory sleep responses to wakefulness induced by the dopamine autoreceptor antagonist (-)ds121. | the effect of the dopamine autoreceptor antagonist (-)ds121 on wakefulness, locomotor activity, body temperature and subsequent compensatory sleep responses was examined in the rat. animals entrained to a light-dark cycle were treated at 5 h after lights-on (ct-5) with 0.5, 1, 5 or 10 mg/kg i.p. (-)ds121 or methylcellulose vehicle. an additional group received 5 mg/kg i.p. (-)ds121 or vehicle 6 h after lights-off (ct-18). at ct-5, (-)ds121 dose-dependently increased wakefulness, locomotor activi ... | 1998 | 9618410 |
| influence of cedar essence on spontaneous activity and sleep of rats and human daytime nap. | we investigated whether exposure to the odor of extracted cedar essence (ce) has (i) an influence on spontaneous activity and sleep-wake states of rats and (ii) a sleep-promoting effect on human daytime nap after taking an ordinary night's sleep. in rats exposed to ce, spontaneous activities and amount of wake were significantly decreased, while the amount of non-rapid eye movement (nrem) sleep was significantly increased. in human daytime nap, nrem sleep stage 2 latency was significantly shorte ... | 1998 | 9628112 |
| age-dependent effect of ketanserin on the sleep-waking phases in rats. | the age-dependent effect of the specific 5-ht2 receptor antagonist ketanserin at two doses (1 mg/kg and 6 mg/kg) on six sleep-waking phases was electroencephalographically (eeg) examined in young, middle-aged, and old male wistar rats. because 5-ht2 receptor binding sites decrease with aging, the question of whether ketanserin can produce any effect on sleep-wake in advanced age was addressed. ketanserin enhanced deep slow wave sleep in the three age groups. however, in the old rats this effect ... | 1998 | 9639243 |
| noradrenaline neurotoxin dsp-4 effects on sleep and brain temperature in the rat. | n-(2-chloroethyl)-n-ethyl-2-bromobenzylamine (dsp-4) has a selective degenerative effect on noradrenergic fibers originating from locus coeruleus (lc) neurons. in the present study, we studied its effect on vigilance states and brain temperature by continuous recordings for periods of 1-5 days and 2-4 weeks following dsp-4 treatment. on the first day, paradoxical sleep duration was significantly decreased (-67%, p < 0.05), slow-wave sleep (sws) duration increased (+16%, p < 0.05) up to 48 h afte ... | 1998 | 9654350 |
| 5-hydroxyindoles compounds and nitric oxide voltammetric detection in the rat brain: changes occurring throughout the sleep-wake cycle. | the release of serotonin may occur throughout the sleep-wake cycle according to 2 different modalities: - by the axonal nerve endings during waking; - by the dendrites and/or the soma of the nucleus raphe dorsalis (nrd) during sleep. neuronal nitric oxide (no), synthesised by constitutive no synthase (nos), is colocalized with neurotransmitters such as gaba, acetylcholine, somatostatin, serotonin, etc. in order to evaluate its modalities of release throughout the rat sleep-wake cycle, a sensor a ... | 1998 | 9660098 |
| [melatonin: a popular hormone]. | this contribution makes an attempt to critically reassess the impressive career of melatonin (mel) from a stepchild of hormone research to a best-seller of drug marketing. melatonin, the hormone of the pineal gland, provides temporal information on diurnal and seasonal variation to the body and brain and it is involved in the synchronization of many different aspects of circadian systems to the light-dark cycle. in addition to these receptor-mediated functions, mel may act as a modulator of intr ... | 1998 | 9676179 |
| measurements of behavior in the naked mole-rat after intraperitoneal implantation of a radio-telemetry system. | the naked mole-rat (heterocephalus glaber) is a unique fossorial mammal that is eusocial, object blind, and virtually poikilothermic. this animal is an ideal model to examine questions pertaining to the thermoregulatory aspects of sleep/wake cycles and other circadian events. however, the monitoring of mammalian sleep usually involves implanting permanent electrodes into the skull which are linked to a counter-weighted cable apparatus. this is not a viable option for h. glaber because of the tun ... | 1998 | 9696320 |
| rolipram, an antidepressant that increases the availability of camp, transiently enhances wakefulness in rats. | a study was carried out on the effects on sleep of rolipram, an antidepressant that increases the availability of camp by inhibiting a phosphodiesterase isoenzyme. rats were treated with rolipram (0.1 or 1 mg/kg) twice a day (at light and dark onset) for 11 days, after a chronic period of injection of physiological saline for habituation purposes. the sleep-wake activity was recorded for 12 h following the injection at light onset on the baseline day (physiological saline), on rolipram days 1, 5 ... | 1998 | 9700966 |
| adrenergic and cholinergic inputs in preoptic area of rats interact for sleep-wake thermoregulation. | isolated studies have shown that both norepinephrine and acetylcholine into the medial preoptico-anterior hypothalamic area tonically regulate sleep-wake and body temperature. a possible interaction between these neurotransmitters for the regulation of such functions has been investigated in this study. to study this interaction a combination of either prazosin and carbachol or, scopolamine and methoxamine was injected into the medial preoptico-anterior hypothalamic area and the effect on sleep, ... | 1998 | 9738535 |
| [are active neurons a better defense against aging in alzheimer's disease?]. | this article deals with the question whether metabolic activity of neurons interferes with their survival during brain aging and alzheimer's disease (ad). this 'use it or lose it' concept assumes that active neurons have a better chance to survive these conditions. we have monitored activity changes in human hypothalamic nuclei, that show differential survival patterns in aging and ad. the size of the golgi apparatus (ga) was measured in e.g. the nucleus basalis of meynert (nbm), that is severel ... | 1998 | 9746932 |
| albumin enhances sleep in the young rat. | rats 4 to 7 days after weaning received intraperitoneal (i.p.) injections of vehicle (baseline day), and either serum (2 ml of lyophilized rabbit serum), 140 mg of rat albumin, or hyperosmotic nacl (experimental day). injections were given 1 h before light onset. sleep-wake activity and cortical brain temperature were recorded during the subsequent 12-h light period. the intensity of non-rapid eye movement sleep (nrems) was characterized by the power density values of the electroencephalogram sl ... | 1998 | 9748091 |
| subdiaphragmatic vagotomy does not block sleep deprivation-induced sleep in rats. | cytokines, such as interleukin-1beta (il-1beta), are involved in physiological sleep regulation and in the sleep responses to sleep deprivation. sleep deprivation increases systemic cytokine levels and recent evidence suggests that cytokine-to-brain communication occurs via the vagus nerve. furthermore, the vagus nerve plays a role in sleep responses elicited by feeding and vagal activity affects electroencephalographic (eeg) activity. thus, this study examined sleep-wake activity and brain temp ... | 1998 | 9748105 |
| brain regional substrates for the actions of the novel wake-promoting agent modafinil in the rat: comparison with amphetamine. | modafinil is a novel wake-promoting compound for which the mechanism and sites of action are unknown. we examined the neural substrates in the brain for the actions of modafinil using 2-deoxyglucose autoradiography and compared the findings to those obtained with amphetamine. modafinil showed a relatively restricted pattern of changes in brain regional metabolic activity, while amphetamine altered glucose utilization in a wide variety of brain regions. both modafinil and amphetamine increased gl ... | 1998 | 9759978 |
| morphological substrates underlying opioid, epinephrine and gamma-aminobutyric acid inhibitory actions in the rat locus coeruleus. | the locus coeruleus (lc) has been implicated in attentional processes related to orienting behaviors, learning and memory, anxiety, stress, the sleep-wake cycle, and autonomic control, as well as to contributing to the affective state. direct activation of lc neurons causes desynchronization of the electroencephalogram, suggesting that the lc is an important modulator of the behavioral state. the lc has been an intensely studied neuronal system, as the physiology and pharmacology of this nucleus ... | 1998 | 9766384 |
| output signals of the scn. | the suprachiasmatic nucleus (scn) of the hypothalamus controls circadian rhythmicity in mammals (for reviews, see refs. 33 and 59). responses modulated by the scn are numerous and include rhythms in sleep/wake cycles, locomotor, gnawing and general activity, temperature, ingestive behavior, and rhythms of hormonal and peptide secretions. though a great deal is known about the neuroanatomical organization of the scn, many elements of the structure-function relationships remain to be discovered. f ... | 1998 | 9787940 |
| daily rhythms in fos activity in the rat ventrolateral preoptic area and midline thalamic nuclei. | the present experiment investigated the expression of the nuclear phosphoprotein fos over the 24-h light-dark cycle in regions of the rat brain related to sleep and vigilance, including the ventrolateral preoptic area (vlpo), the paraventricular thalamic nucleus (pvt), and the central medial thalamic nucleus (cmt). immunocytochemistry for fos, an immediate-early gene product used as an index of neuronal activity, was carried out on brain sections from rats perfused at zeitgeber time (zt) 1, zt 5 ... | 1998 | 9791082 |
| the fasciculus retroflexus controls the integrity of rem sleep by supporting the generation of hippocampal theta rhythm and rapid eye movements in rats. | the fasciculus retroflexus (fr) fiber bundle comprises the intense cholinergic projection from the medial division of the habenula nucleus (hbn) of the epithalamus to the interpeduncular nucleus (ipn) of the limbic midbrain. due to the widespread connections of the hbn and ipn, it could be surmised that the fr is integrated in the processings of various subsystems that are known to be involved in the sleep-wake mechanisms; relevant sites include the limbic forebrain and midbrain areas and more c ... | 1998 | 9820735 |
| localization of nitric oxide-synthesizing neurons sending projections to the dorsal raphe nucleus of the rat. | the origin of the nerve fibers immunoreactive for neuronal nitric oxide synthase (nnos) in the rat dorsal raphe nucleus (drn) was determined by combining the use of cholera toxin subunit b (ctb) as a retrograde tracer and nnos immunohistochemistry with a monoclonal anti-nnos antibody. double labeled ctb-nnos cell bodies were distributed from the rostral diencephalon to the caudal medulla oblongata, in about 20 areas of the brain. several of the areas displaying double labeled cells are known for ... | 1998 | 9870341 |
| endogenous nitric oxide in the rat pons promotes sleep. | pontine cholinergic structures are known to play a key role in the regulation of vigilance states associated with desynchronised eeg, i. e., wakefulness and paradoxical sleep. as the cholinergic cells of these nuclei, the pedunculopontine tegmentum (ppt) and the laterodorsal tegmentum, are enriched with nitric oxide synthase (nos), we tested the hypothesis that nitric oxide (no) in the pons is implicated in wake and sleep regulation. for this reason, a nos inhibitor, a no precursor and a no dono ... | 1999 | 9878741 |
| manipulations during forced wakefulness have differential impact on sleep architecture, eeg power spectrum, and fos induction. | we propose a hypothesis suggesting that the most prominent experiences occurring during wakefulness activate specific clusters of neurons related to such experiences. these neurons could possibly then evoke the release of various types of sleep-inducing molecules, thereby causing different patterns of sleep architecture. in this study, we therefore sought to determine whether manipulations of behavior during wakefulness, such as forced wakefulness induced by gentle handling, forced wakefulness a ... | 1998 | 9886782 |
| ionic mechanisms of action of neurotensin in acutely dissociated neurons from the diagonal band of broca of the rat. | whole cell recordings were performed on acutely dissociated neurons from the horizontal limb of the diagonal band of broca (hdbb) from rats to elucidate the ionic mechanisms of action of neurotensin. neurotensin caused a decrease in whole cell voltage-activated outward currents and failed to elicit a response when ca2+ influx was blocked by changing the external solution to the one containing 0 mm ca2+ and 50 microm cd2+, suggesting the involvement of ca2+-dependent conductances. charybdotoxin, ... | 1999 | 9914284 |
| prostaglandin d2 and sleep regulation. | prostaglandin (pg) d2 is recognized as the most potent endogenous sleep-promoting substance whose action mechanism is the best characterized among the various sleep-substances thus far reported. the pgd2 concentration in rat cerebrospinal fluid (csf) shows a circadian change coupled to the sleep-wake cycle and elevates with an increase in sleep propensity during sleep deprivation. lipocalin-type pgd synthase is dominantly produced in the arachnoid membrane and choroid plexus of the brain, and is ... | 1999 | 9989291 |
| intrapreoptic microinjection of ghrh or its antagonist alters sleep in rats. | previous reports indicate that growth hormone-releasing hormone (ghrh) is involved in sleep regulation. the site of action mediating the nonrapid eye movement sleep (nrems)-promoting effects of ghrh is not known, but it is independent from the pituitary. ghrh (0.001, 0. 01, and 0.1 nmol/kg) or a competitive antagonist of ghrh (0.003, 0.3, and 14 nmol/kg) was microinjected into the preoptic area, and the sleep-wake activity was recorded for 23 hr after injection in rats. ghrh elicited dose-depend ... | 1999 | 10066272 |
| insulin-like growth factor-1 (igf-1)-induced inhibition of growth hormone secretion is associated with sleep suppression. | the hypothalamic growth hormone (gh)-releasing hormone (ghrh) promotes non-rapid eye movement sleep (nrems). insulin-like growth factor-1 (igf-1) acts as a negative feedback in the somatotropic axis inhibiting ghrh and stimulating somatostatin. to determine whether this feedback alters sleep, rats and rabbits were injected intracerebroventricularly (i.c.v.) with igf-1 (5.0 and 0.25 microgram, respectively) and the sleep-wake activity was studied. compared to baseline (i.c.v. injection of physiol ... | 1999 | 10082812 |
| fos expression in the sleep-active cell group of the ventrolateral preoptic area in the diurnal murid rodent, arvicanthis niloticus. | the ventrolateral preoptic area (vlpo) of the nocturnal laboratory rat receives direct input from the retina and is active during sleep; however, nothing is known about vlpo function in day-active (diurnal) species. in the first study, we used 24-h videotaping of arvicanthis niloticus, a diurnal murid rodent, to estimate the distribution of sleep and wakefulness across a 12:12 light-dark cycle. based on behavioral data, a. niloticus were perfused at a time when the animals are inactive (zeitgebe ... | 1999 | 10082823 |
| sino-aortic denervation augments the increase in blood pressure seen during paradoxical sleep in the rat. | using a computer assisted telemetric system, we have re-examined the effect of sino-aortic denervation (sad) on the changes in arterial blood pressure (ap) and heart rate (hr) during sleep in the rat suitably recovered from the operation. eight 1 hourly polygraphic recordings were performed 4 weeks after the initial sad surgery. in the sad rats, the increase in ap during paradoxical sleep (ps) was much larger than that in sham-operated rats. hr in the sad rats increased on-going from slow-wave s ... | 1999 | 10188135 |
| neurotolerability of gadobenate dimeglumine in a rat model of focal brain ischemia: eeg evaluation. | the neurologic pathologies for which contrast-enhanced mri is indicated are often accompanied by a disruption of the blood-brain barrier (bbb), which allows the contrast agent to come into contact with the nervous tissue. thus, assessment of the neurologic safety for a new contrast agent is of crucial importance. the objective of this study was to assess the neurotolerability of the new mri contrast agent gadobenate dimeglumine using eeg in the presence of focal lesions of the bbb. | 1999 | 10196717 |
| age-related changes in sleep in the rat. | human sleep in old age is characterized by a number of changes, including reductions in sleep efficiency, amounts of visually scored slow-wave and rem sleep, and amplitude of the diurnal sleep/wake rhythm. in older rats, some, but not all, of these traits have been reported, including a decrease in the mean duration of sleep bouts, an increase in the number of sleep bouts, and a modest reduction of rem sleep. studies of the diurnal rhythm of total sleep have had varied results. there are, howeve ... | 1999 | 10201059 |
| subnuclear organization of the rat habenular complexes. | the habenular complexes represent phylogenetically constant structures in the diencephalon of all vertebrates. available evidence suggests that this area is engaged in a variety of important biological functions, such as reproductive behaviors, central pain processing, nutrition, sleep-wake cycles, stress responses, and learning. based on nissl-stained sections, one medial nucleus and two lateral nuclei (divisions) have been widely accepted in the rat. cytochemical, hodologic, and functional stu ... | 1999 | 10213193 |
| region-dependent difference in the sleep-promoting potency of an adenosine a2a receptor agonist. | the present study has demonstrated that the sleep-promoting potency of 2-[p-(2-carboxyethyl)phenethylamino]-5'-n-ethylcarboxamido adenosine (cgs21680), a selective agonist for the adenosine a2a receptor, varies depending on the location of the administration. cgs21680 was continuously administered to rats through a chronically implanted cannula for 6 h during their active phase. the tip of the cannula was located in the subarachnoid space or the brain ventricle neighbouring the established brain ... | 1999 | 10215911 |
| acute and chronic blood pressure response to recurrent acoustic arousal in rats. | repetitive episodic hypoxia every 30 sec administered chronically to sprague-dawley (sd) rats has been shown by previous studies to cause a sustained increase in daytime blood pressure (bp). acoustic arousal in humans during wake or sleep produces an acute bp rise. the question then arises as to whether chronic episodic acoustic arousal applied with the same frequency and duration as episodic hypoxia induces elevated bp. we exposed 14-week-old (n = 10) sd rats in individual cages to recurrent bu ... | 1999 | 10342789 |
| hippocampal type 1 (movement-related) theta rhythm positively correlates with serotonergic activity. | to investigate the relationship between the hippocampal [symbol: see text] activity (or rhythmical slow activity, rsa) and the hippocampal serotonergic activity during spontaneous behavior, simultaneous recordings of i) hippocampal eeg, ii) sleep-wake activity, and iii) hippocampal levels of the serotonin (5-ht) metabolite 5-hydroxyndolacetic acid (5-hiaa--measured by in vivo voltammetry and infrared telemetry) were performed. the results show that hippocampal type 1 rsa recorded during wakefuln ... | 1999 | 10349493 |
| hypothalamic serotonergic activity correlates better with brain temperature than with sleep-wake cycle and muscle tone in rats. | the activity of the serotonergic system varies in phase with the sleep-wake cycle, which is associated with changes in several physiological functions, including electroencephalographic activity, brain temperature, and locomotion. the aim of the present study was to clarify which of these parameters correlates better with serotonergic activity in spontaneous conditions. voltammetric recordings by telemetry of serotonergic metabolism in the medial preoptic area and polygraphic recordings of sleep ... | 1999 | 10362311 |
| automated sleep staging systems in rats. | one of the major inconveniences encountered in sleep studies is the time consuming labor involved in equating visual analysis of physiological recordings (eeg, emg, eog, ...) to an appropriate state of vigilance. the explosion of computer technology is responsible for the emergence of several automated sleep-wake staging systems to supplement human analysis. conversely to human sleep analysis, rat sleep is characterized by the absence of consensus about numerous elements constituting the sleep-w ... | 1999 | 10389657 |
| a comparative study of quiet sleep, active sleep, and waking on the first 2 days of life. | direct behavioral observation and motility monitoring procedures provide reliable data, and both are appropriate for sleep/wake state measurements starting immediately after birth. using these procedures, newborn rats, rabbits, and humans were found to have a greater amount of quiet sleep on the day of birth rather than 24 hr later. changes in active sleep and wake were inconsistent across the 2 days. the quiet sleep findings are contrary to the developmental course which increases with age. the ... | 1999 | 10397895 |
| nitric oxide and sleep in the rat: a puzzling relationship. | to date, only a few studies indicate that nitric oxide may play a role in the regulation of the sleep-wake cycle. however, data reported are controversial and the part played by nitric oxide in sleep-wake cycle regulation still remains uncertain. in the present report, we studied the effects on sleep amounts of two different nitric oxide synthase inhibitors: n-nitro-l-arginine methyl ester, a non-selective nitric oxide synthase inhibitor, and 7-nitro-indazole, a specific inhibitor of neuronal ni ... | 1999 | 10408611 |
| blockade of 5-hydroxytryptamine (serotonin)-2 receptors alters interleukin-1-induced changes in rat sleep. | recent data suggest that interleukin-1-induced enhancement of non-rapid eye movement sleep is mediated, in part, by the serotonergic system. to determine if sleep changes induced by interleukin-1 are mediated by a specific serotonergic receptor subtype, we evaluated interleukin-1 effects on sleep in rats pretreated with the 5-hydroxytryptamine (serotonin)-2 receptor antagonist ritanserin. ritanserin (0.63 mg/kg, intraperitoneally) by itself did not alter sleep-wake behavior, although it did redu ... | 1999 | 10408622 |
| critical threshold cerebral hypoperfusion causes alzheimer's disease? | after nearly a century of inquiry, the cause of alzheimer's disease (ad) remains to be found. in this review, basic and clinical evidence is presented that assembles and hypothetically explains most of the key pathologic events associated with the development of ad. these pathologic events are triggered in ad by an impaired cerebral perfusion originating in the microvasculature which affects the optimal delivery of glucose and oxygen and results in a breakdown of metabolic energy pathways in bra ... | 1999 | 10412794 |
| hypoprolactinemic rats under conditions of constant darkness or constant light. effects on the sleep-wake cycle, cerebral temperature and sulfatoxymelatonin levels. | in genetic hypoprolactinemic rats under light-dark (ld) conditions, the circadian rhythms of slow-wave (sws) and paradoxical (ps) sleep display an alteration of their phase relationship. the aim of our study was to investigate the effects of constant darkness (dd) or constant light (ll) on the daily distribution and amounts of sleep-wake stages, cerebral temperature and concentrations of the urinary melatonin metabolite, 6-sulfatoxymelatonin, in prolactin-deficient rats. after 3 weeks of dd, the ... | 1999 | 10415384 |
| retinal input to the sleep-active ventrolateral preoptic nucleus in the rat. | light-dark periodicity and luminance play important roles in regulating sleep-wake cycles. we recently identified a discrete cluster of sleep-active cells in the ventrolateral preoptic nucleus that we hypothesize plays a central role in sleep regulation. these ventrolateral preoptic nucleus neurons are gabaergic and galaninergic and innervate the monoaminergic cell groups that contribute to the ascending arousal system. to determine whether there are retinal inputs to sleep-active ventrolateral ... | 1999 | 10430484 |
| immunohistochemical distribution of the somatostatin receptor subtype 5 in the adult rat brain: predominant expression in the basal forebrain. | somatostatin exerts its actions by means of a family of g protein-coupled receptors, five of which have so far been cloned. whereas mrnas for receptor subtypes sst(1)-sst(4) have been unequivocally localized in the brain, the data concerning the fifth subtype, sst(5), are contradictory. moreover, whereas sst(1) and sst(2a) receptor proteins have been localized by immunohistochemistry, the distribution of sst(3)-sst(5) receptor proteins and/or subtype-specific binding remains to be determined in ... | 1999 | 10440710 |
| forced desynchrony of circadian rhythms of body temperature and activity in rats. | the daily rhythm in body temperature is thought to be the result of the direct effects of activity and the effects of an endogenous circadian clock. forced desynchrony (fd) is a tool used in human circadian rhythm research to disentangle endogenous and activity-related effects on daily rhythms. in the present study, we applied an fd protocol to rats. we subjected 8 rats for 5 days to a 20 h forced activity cycle consisting of 10 h of forced wakefulness and 10 h for rest and sleep. the procedure ... | 1999 | 10442237 |
| psychogenetically selected (roman high- and low-avoidance) rats differ in 24-hour sleep organization. | a comparison of sleep organization in roman high-(rha/verh) and low-(rla/verh) avoidance rats, which differ in the way they respond to environmental stimuli and in several neuroendocrine and neurochemical parameters, was carried out. eeg-sleep recordings were obtained from adult males over 12:12 light-dark periods to determine how these two psychogenetically selected rat lines might also differ in their sleep-wake cycle. there was no significant difference in total sleep time between the two lin ... | 1999 | 10452334 |
| orexin a activates locus coeruleus cell firing and increases arousal in the rat. | the localization of orexin neuropeptides in the lateral hypothalamus has focused interest on their role in ingestion. the orexigenic neurones in the lateral hypothalamus, however, project widely in the brain, and thus the physiological role of orexins is likely to be complex. here we describe an investigation of the action of orexin a in modulating the arousal state of rats by using a combination of tissue localization and electrophysiological and behavioral techniques. we show that the brain re ... | 1999 | 10485925 |
| high corticosterone levels in prenatally stressed rats predict persistent paradoxical sleep alterations. | prenatal stress predisposes rats to long-lasting disturbances that persist throughout adulthood (e.g., high anxiety, dysfunction of the hypothalamo-pituitary-adrenal axis, and abnormal circadian timing). these disturbances parallel to a large extent those found in depressed patients, in which hypercortisolemia and sleep alterations may be related to stress-inducing events. we studied sleep-wake parameters in control and prenatally stressed adult rats (3-4 months old) and examined possible relati ... | 1999 | 10493766 |
| chronic, low-level exposure to the cholinesterase inhibitor dfp. ii. time course of behavioral state changes in rats. | rats were repeatedly administered with low doses of diisopropylfluorophosphate (dfp; 0.2 mg/kg/day, sc), an irreversible cholinesterase (che) inhibitor. control rats received a daily injection of oil vehicle or of saline. recordings of the sleep-wake states were obtained in the 6 h following 1, 3, 6, 9, 13, 17, and 21 injections, as well as 2, 4, and 19 days after 9-day treatment. dfp administration increased waking at the expense of slow-wave sleep (sws), but not of paradoxical sleep (ps); as a ... | 1999 | 10495004 |
| choline acetyltransferase expression during periods of behavioral activity and across natural sleep-wake states in the basal forebrain. | the present study examined whether the expression of the messenger rna encoding the protein responsible for acetylcholine synthesis is associated with sleep-wakefulness. choline acetyltransferase messenger rna levels were analysed using a semi-quantitative assay in which reverse transcription was coupled to complementary dna amplification using the polymerase chain reaction. to examine the relationship between steady-state messenger rna and behavioral activity, rats were killed during the day (4 ... | 1999 | 10501461 |
| gadolinium chloride pretreatment prevents cafeteria diet-induced sleep in rats. | the liver kupffer cells constitute the largest population of fixed macrophages in the body and reside at a strategic position in liver sinusoids to interact with mediators from the gut. previously, we showed that cafeteria feeding increases sleep by a subdiaphragmatic mechanism and increases interleukin-1beta (il-1beta) mrna expression in rat liver and brain. thus, the aim of the present experiment was to test the hypothesis that macrophages, in particular liver kupffer cells, contribute to the ... | 1999 | 10505816 |
| gabaa receptor modulation of temperature sensitive neurons in the diagonal band of broca in vitro. | several regions of the brain, including the horizontal limb of the diagonal band of broca (hdb), contain neurons that are responsive to changes in local temperature. these neurons are hypothesized to participate in thermoregulation and sleep-wake control. the hdb contains a large number of gamma-aminobutyric acid (gaba) terminals, and it has many neurons that utilize gaba as a neurotransmitter. therefore, in this study we characterized the in vitro effects of the gabaa receptor agonist muscimol ... | 1999 | 10536201 |
| pituitary adenylyl cyclase-activating peptide: a pivotal modulator of glutamatergic regulation of the suprachiasmatic circadian clock. | the circadian clock in the suprachiasmatic nucleus (scn) of the hypothalamus organizes behavioral rhythms, such as the sleep-wake cycle, on a near 24-h time base and synchronizes them to environmental day and night. light information is transmitted to the scn by direct retinal projections via the retinohypothalamic tract (rht). both glutamate (glu) and pituitary adenylyl cyclase-activating peptide (pacap) are localized within the rht. whereas glu is an established mediator of light entrainment, ... | 1999 | 10557344 |
| sleep impairments in rats implanted with morphine pellets. | morphine pellets (2 x 75 mg) were subcutaneously implanted in rats and vigilance states (wakefulness, slow wave sleep and paradoxical sleep) were observed during ten days. significant impairment of each vigilance state distribution appeared during the first days of morphine dependence. although waking and slow wave sleep were not affected during the last days, paradoxical sleep duration was reduced during dependence. nevertheless, the sleep-wake circadian rhythm was not abolished. these results ... | 1999 | 10559705 |
| the burst-suppression electroencephalogram. | the burst-suppression (bs) pattern of the eeg occurs in a rather limited number of conditions. it has been observed in deep stages of general anesthesia and in conjunction with sedative overdoses. it is also known to occur in the wake of cardiorespiratory arrest. undercutting of the cortex has been found to result in bs activity. rare neonatal epileptic encephalopathies also give rise to bs. our personal interest was prompted by the consistent finding of bs activity in rats following cerebral an ... | 1999 | 10578472 |
| mirtazapine, a mixed-profile serotonin agonist/antagonist, suppresses sleep apnea in the rat. | serotonin enhancing drugs, including l-tryptophan and, more recently, fluoxetine and paroxetine, have been tested as pharmacologic treatments for sleep apnea syndrome. although some patients have demonstrated reduced apnea expression after treatment with these compounds, this improvement has been restricted to nonrapid eye movement (nrem) sleep, with some patients showing no improvement. this study reports the effects of mirtazapine, an antidepressant with 5-ht(1) agonist as well as 5-ht(2) and ... | 1999 | 10588592 |
| adenosinergic modulation of rat basal forebrain neurons during sleep and waking: neuronal recording with microdialysis. | 1. the cholinergic system of the basal forebrain (bf) is hypothesized to play an important role in behavioural and electrocortical arousal. adenosine has been proposed as a sleep-promoting substance that induces sleep by inhibiting cholinergic neurons of the bf and brainstem. however, adenosinergic influences on the activity of bf neurons in naturally awake and sleeping animals have not been demonstrated. 2. we recorded the sleep-wake discharge profile of bf neurons and simultaneously assessed a ... | 1999 | 10601498 |
| pituitary crh receptor blockade reduces waking in the rat. | we have previously hypothesized that corticotropin-releasing hormone (crh) is involved in the regulation of physiological waking. central administration of crh receptor antagonists reduces spontaneous waking in the rat. some of the responses to central administration of crh receptor antagonists may be mediated by mechanisms involving the hypothalamic-pituitary-adrenal axis, either by direct actions on the hypothalamus or by actions at the level of the pituitary due to leakage of the antagonists ... | 1999 | 10604839 |
| studies on sleep/wake effects of serotonin reuptake inhibitors and receptor subtype involvement. | studies with the serotonin uptake inhibitors zimeldine and alaproclate show biphasic effects on the sleep/wake axis in rats and cats. zimeldine induced an initial waking response succeeded by a small sws-2 increase in rats. the waking increase was not blocked by the 5-ht2 antagonist ritanserin nor by the putative 5-ht1a antagonist (-)-alprenolol. in cats, zimeldine induced initial behavioural changes which were succeeded by a large sws-2 increase. alaproclate gave similar initial responses as zi ... | 1992 | 10607045 |
| dynamic changes in hypothalamic monoamines during sleep/wake cycles assessed by parallel eeg and microdialysis in the rat. | monoaminergic changes during sleep/wake cycles were investigated in the rostral hypothalamic areas since feeding, metabolism and sleep were shown to be causally related. thus, the microdialysis probe was located stereotaxically in the ventromedial and paraventricular nuclei and cemented together with cortical electrodes for eeg sleep recordings. the monoaminergic changes were extensively investigated. sampling of dialysates over six minutes in freely behaving rats showed an increase in 5-ht and ... | 1995 | 10607153 |
| relationship of activity in the subthalamic nucleus-globus pallidus network to cortical electroencephalogram. | one of the functions of the excitatory subthalamic nucleus (stn) is to relay cortical activity to other basal ganglia structures. the response of the stn to cortical input is shaped by inhibition from the reciprocally connected globus pallidus (gp). to examine the activity in the stn-gp network in relation to cortical activity, we recorded single and multiple unit activity in stn and/or gp together with cortical electroencephalogram in anesthetized rats during various states of cortical activati ... | 2000 | 10632612 |
| density of perfused brain capillaries in the aged rat during the wake-sleep cycle. | structural and functional age-related changes in brain vasculature might affect the cerebral microcirculation. the present study evaluated the density of perfused brain capillaries and the perfusion fraction (perfused/existing capillaries) in aged rats (24 months) during the states of the wake-sleep cycle (quiet wakefulness, quiet sleep, active sleep) characterized by different levels of brain activation. the number of perfused capillaries was determined by intravascular injection of the fluores ... | 2000 | 10638443 |
| involvement of the caudal raphe nuclei in the feeding behavior of rats. | involvement of the caudal raphe nuclei (raphe pallidus, rpa; raphe magnus, rmg, and raphe obscurus, rob) in feeding behavior of adult rats was studied by measuring c-fos protein expression, in animals submitted to the "meal-feeding" model of food restriction in which the rats were fed ad libitum only from 7:00 to 9:00 h, for 15 days. the experimental groups submitted to chronic fasting, named 'search for food' (sf), 'ingestion of food' (if) and 'satiety of food' (saf) were scheduled after a prev ... | 2000 | 10657063 |
| 5-hydroxytryptophan, but not l-tryptophan, alters sleep and brain temperature in rats. | the precise role of serotonin (5-hydroxytryptamine) in the regulation of sleep is not fully understood. to further clarify this role for 5-hydroxytryptamine, the 5-hydroxytryptamine precursors l-tryptophan (40 and 80 mg/kg) and l-5-hydroxytryptophan (25-, 50-, 75-, 100 mg/kg) were injected intraperitoneally into freely behaving rats 15 min prior to dark onset, and subsequent effects on sleep-wake activity and cortical brain temperature were determined. l-5-hydroxytryptophan, but not l-tryptophan ... | 2000 | 10658624 |
| diurnal variation in orexin a immunoreactivity and prepro-orexin mrna in the rat central nervous system. | orexins are a family of neuropeptides originally believed to be important mediators of food intake. the wide distribution of orexins and their receptors, however, has suggested other regulatory functions for these peptides including involvement in sleep and arousal mechanisms. in this study, we have demonstrated diurnal variation in orexin a immunoreactivity in the pons, from where locus coeruleus noradrenergic neurones innervate other brain areas to stimulate arousal, and in the preoptic/anteri ... | 2000 | 10674633 |
| a new method for continuous, long-term polysomnographic recording of neonatal rats. | many findings suggest that in altricial mammals neonatal rem sleep has developmental functions. however, investigations of these developmental functions has been hampered by technical limitations of the conventional polysomnographic (psg) recording technique. one limitation is that continuous (24 hour/day), long-term (weeks) psg recordings have not been achieved. a second limitation is that the metal screw electrodes and head plugs cemented to the skull cannot be removed to allow the neonate to ... | 2000 | 10678461 |
| a sparse projection from the suprachiasmatic nucleus to the sleep active ventrolateral preoptic area in the rat. | the circadian clock of the suprachiasmatic nucleus (scn) may control the sleep-wake cycle by modulating the activity of brain regions important in sleep onset and maintenance, such as the ventrolateral preoptic area (vlpo). the aim of this study was to determine whether the vlpo receives direct projections from the scn. the retrograde tracer cholera toxin (beta subunit; ct beta) was injected into the vlpo of male rats and the scn was examined for the presence of labeled, vlpo-projecting neurons. ... | 2000 | 10683837 |
| cholinergic modulation of respiratory brain-stem neurons and its function in sleep-wake state determination. | 1. shifts in behavioural state are controlled by reciprocal changes in discharge of cholinergic and aminergic groups of brain-stem/pontine neurons. during rapid eye movement (rem) sleep, cholinergic neurons are most active and aminergic neurons are least active. 2. significant changes occur in the central control of breathing during rem sleep; respiration rate increases in frequency and variability, brain-stem respiratory neuron discharge is generally enhanced and the outputs of some respiratory ... | 2000 | 10696542 |
| effects of sleep deprivation on sleep and sleep eeg in three mouse strains: empirical data and simulations. | gene targeted mice can be used as models to investigate the mechanisms underlying sleep regulation. three commonly used background strains for gene targeting (129/ola, 129/svj and c57bl/6j) were subjected to 4-h and 6-h sleep deprivation (sd), and their sleep and sleep eeg were continuously recorded. the two-process model of sleep regulation has predicted the time course of slow-wave activity (swa) in nonrem sleep after several sleep-wake manipulations in humans and the rat [3] [9]. we tested th ... | 2000 | 10700548 |
| the novel brain neuropeptide, orexin-a, modulates the sleep-wake cycle of rats. | orexin-a is a novel neuropeptide initially isolated from hypothalamic extracts but now known to be present in fibres distributed throughout the rat cns including many regions associated with sleep-wake regulation. the recognition of a particularly dense innervation of orexinergic nerves in the locus coeruleus, together with the observed increase in firing rate of locus coeruleus neurons following application of orexin-a in vitro, further highlighted a potential involvement of the peptide in modu ... | 2000 | 10712652 |
| sleep in the wistar-kyoto rat, a putative genetic animal model for depression. | the wistar-kyoto (wky) rat exhibits several behavioral and hormonal abnormalities often associated with depression. one of the hallmarks of depression consists of alterations in the sleep-wake cycle, particularly in rapid eye movement (rem) sleep. if the wky rat is indeed an animal model for depression, we hypothesized that it should also show sleep abnormalities relative to the control strain, the wistar (wis) rat under baseline conditions, wky rats showed a 50% increase in total rem sleep time ... | 2000 | 10718326 |
| molecular mechanisms of sleep-wake regulation: a role of prostaglandin d2. | prostaglandin (pg) d2 is a major prostanoid in the brains of rats and other mammals, including humans. when pgd synthase (pgds), the enzyme that produces pgd2 in the brain, was inhibited by the intracerebroventricular infusion of its selective inhibitors, i.e. tetravalent selenium compounds, the amount of sleep decreased both time and dose dependently. the amount of sleep of transgenic mice, in which the human pgds gene had been incorporated, increased several fold under appropriate conditions. ... | 2000 | 10724461 |
| prenatal protein malnourished rats show changes in sleep/wake behavior as adults. | prenatal protein malnutrition significantly elevates brain levels of serotonin in rats, and these levels remain elevated throughout their lives. this biogenic amine is involved in the regulation of many physiological functions, including the normal sleep/wake cycle. the present study examined the effects of prenatal protein malnutrition on the sleep/wake cycle of freely moving adult rats. six prenatally protein malnourished (6% casein) and 10 well-nourished (25% casein) male rats (90-120-day-old ... | 2000 | 10733692 |
| an instrumental method for long-term continuous rem sleep deprivation of neonatal rats. | the present study describes a new method for instrumental rem sleep deprivation (rsd) of neonatal rats. | 2000 | 10737334 |
| down-regulation of orexin gene expression by severe obesity in the rats: studies in zucker fatty and zucker diabetic fatty rats and effects of rosiglitazone. | orexins (hypocretins) are lateral hypothalamic neuropeptides implicated in regulating feeding and the sleep-wake cycle. to study their possible relevance to obesity and diabetes, we measured hypothalamic prepro-orexin mrna levels in obese, normoglycemic zucker fatty (fa/fa) and in hyperglycemic, non-obese zucker diabetic fatty (zdf) rats. hypothalamic prepro-orexin mrna concentrations in zucker fatty rats were 31% lower than those in lean controls (0. 69+/-0.06 vs. 1.00+/-0.10 arbitrary units, p ... | 2000 | 10814839 |
| inhibitory effects of low doses of melatonin on induction of preneoplastic liver lesions in a medium-term liver bioassay in f344 rats: relation to the influence of electromagnetic near field exposure. | we have previously reported that exposures of f344 male rats to both 900 mhz and 1.5 ghz electro-magnetic near fields (emfs) results in slightly decreased numbers and areas of glutathione s-transferase (gst-p)-positive liver foci, liver preneoplastic lesions in rats, in a medium-term liver bioassay (k. imaida, m. taki, t. yamaguchi, t. ito, s. watanabe, k. wake, a. aimoto, y. kamimura, n. ito, t. shirai, lack of promoting effects of the electromagnetic near-field used for cellular phones (929.2 ... | 2000 | 10814886 |
| [oscillations in the oxidation-reduction potential of the brain tissue in rats developing during wakefulness and slow-wave sleep]. | variations of the brain cortex redox state potential (e) were recorded in freely moving white rats (mass of 300-350 g) with implanted platinum electrodes (with the platinum reference electrode in the nasal bone) during sleep-wake cycles. it was found that transitions from the slow-wave sleep to wakefulness were accompanied in the number of cortical areas (metabolic-active sites) by the e rise, while the transitions from the wakefulness to slow-ware sleep were associated with a drop of e. however ... | 2000 | 10822845 |
| article reviewed: the novel brain neuropeptide, orexin-a, modulates the sleep-wake cycle of rats. | | 2000 | 10828439 |
| neuromodulation of the prefrontal cortex during sleep: a microdialysis study in rats. | to test the hypothesis that biogenic amines of the prefrontal cortex are involved in state-dependent cortical and behavioural activation, changes in extracellular levels of serotonin (5-ht), dopamine (da), and noradrenaline (na) were determined during the sleep-wake cycle in freely moving rats using microdialysis probes with parallel eeg recording. serotonin gradually increased up to 450% during wakefulness (w) as compared to slow wave sleep (sws), before decreasing toward stable levels during t ... | 2000 | 10852212 |
| changes in rem sleep occurrence due to rhythmical auditory stimulation in the rat. | the effects of the rhythmical delivery of an auditory stimulus (1000 hz, from 50 to 100 db, 20 ms, every 20 s) on the pattern of rapid eye movement (rem) sleep occurrence was studied in the rat. the stimulation was simultaneously carried out on pairs of rats over 5 consecutive days (10-h recording sessions), during which a tone of increasing intensity (50, 63, 75, 88, 100 db) was used. in each experimental session, auditory stimulation was triggered by the rem sleep occurrence of one rat (rems-s ... | 2000 | 10854576 |
| infusion of adenylyl cyclase inhibitor sq22,536 into the medial pontine reticular formation of rats enhances rapid eye movement sleep. | microinjection of cholinergic and adenosinergic agonists into the medial pontine reticular formation of rats produces long lasting increases in the time spent in rapid eye movement sleep. several g-protein-coupled muscarinic and adenosinergic receptors share a common action of inhibition of adenylyl cyclase and inhibition of cyclic adenosine monophosphate. inhibition of cyclic adenosine monophosphate has been implicated in the mechanism of rapid eye movement sleep induction in the cat. we sought ... | 2000 | 10854762 |
| effects of cholinomimetic injection into the brain stem reticular formation on halothane anesthesia and antinociception in rats. | the brain stem reticular formation plays an important role in determining consciousness and arousal. modulation of cholinergic neurotransmission in this region alters the sleep-wake cycle. in the present study, we examined the effect of the direct application of cholinergic agents into the pontine reticular nucleus on anesthetic requirements and recovery and antinociception in rats. sprague-dawley rats were implanted with 24-gauge guide cannulas 1.0 mm above the oral portion of pontine reticular ... | 2000 | 10869384 |
| distribution of orexin-a and orexin-b (hypocretins) in the rat spinal cord. | orexin-a and orexin-b (also known as hypocretin-1 and hypocretin-2) are hypothalamic peptides that regulate feeding behavior, energy metabolism, and sleep-wake cycle. we determined the distribution of orexin-a and -b in the rat spinal cord, using sensitive radioimmunoassays and an immunohistochemical technique with three antisera specific for these orexins. orexins were distributed throughout the spinal cord, and their contents were highest in the cervical region. orexin fibers were concentrated ... | 2000 | 10876067 |
| diurnal variations in lipopolysaccharide-induced sleep, sickness behavior and changes in corticosterone levels in the rat. | inoculation of rats with microorganisms or microbial constituents that activate host defense promotes non-rapid eye movement sleep (non-rems) and suppresses rems. in this study, we evaluated circadian influences on the effects of lipopolysaccharide (lps) on sleep, sickness behavior and plasma corticosterone levels in the rat. three sets of experiments were performed. in each, the animals were intraperitoneally injected with vehicle for lps (30 microg/kg) during 2 consecutive days, at the beginni ... | 2000 | 10878499 |
| effects of glutamate agonist versus procaine microinjections into the basal forebrain cholinergic cell area upon gamma and theta eeg activity and sleep-wake state. | serving as the ventral, extra-thalamic relay from the brainstem reticular activating system to the cerebral cortex, basal forebrain neurons, including importantly the cholinergic cells therein, are believed to play a significant role in eliciting and maintaining cortical activation during the states of waking and paradoxical sleep. the present study was undertaken in rats to examine the effects upon electroencephalogram (eeg) activity and sleep-wake state of inactivating basal forebrain neurons ... | 2000 | 10886356 |
| high doses of systemic dhea-sulfate do not affect sleep structure and elicit moderate changes in non-rem sleep eeg in rats. | the hormone dehydroepiandrosterone (dhea) and its metabolite dhea-sulfate (dheas) occur in huge quantities in the plasma as well as in the brain of vertebrates. to investigate whether dheas modulates sleep-wake behavior, we assessed the sleep response to three doses (25, 50, and 100 mg/kg) of intraperitoneally administered dheas, mixed with oil, in 8 rats. dheas injections produced dose-dependent and long-lasting elevations in the plasma levels of both dheas and dhea. dheas administration did no ... | 2000 | 10913777 |
| il-1 is a mediator of increases in slow-wave sleep induced by crh receptor blockade. | we hypothesize that corticotropin-releasing hormone (crh), a regulator of the hypothalamic-pituitary-adrenal (hpa) axis, is involved in sleep-wake regulation on the basis of observations that the crh receptor antagonist astressin, after a delay of several hours, reduces waking and increases slow-wave sleep (sws) in rats. this delay suggests a cascade of events that begins with the hpa axis and culminates with actions on sleep regulatory systems in the central nervous system. one candidate mediat ... | 2000 | 10956236 |
| suprachiasmatic nucleus projections to the paraventricular thalamic nucleus in nocturnal rats (rattus norvegicus) and diurnal nile grass rats (arviacanthis niloticus). | the circadian pacemaker of the suprachiasmatic nucleus (scn) is likely to control the timing of the sleep-wake cycle in mammals by modulating the daily activity patterns of brain regions important in sleep and wakefulness. one such brain region is the paraventricular nucleus of the thalamus (pvt). in both nocturnal rats and the diurnal rodent arvicanthis niltoicus (nile grass rat), expression of fos (the product of the immediate-early gene c-fos) in the pvt increases at times of day when the ani ... | 2000 | 10960599 |
| role of the lateral preoptic area in sleep-related erectile mechanisms and sleep generation in the rat. | penile erections are a characteristic phenomenon of paradoxical sleep (ps), or rapid eye movement sleep. although the neural mechanisms of ps-related erections are unknown, the forebrain likely plays a critical role (schmidt et al., 1999). the preoptic area is implicated in both sleep generation and copulatory mechanisms, suggesting it may be a primary candidate in ps erectile control. continuous recordings of penile erections, body temperature, and sleep-wake states were performed before and up ... | 2000 | 10964969 |