Biomedical subjects

S Tufik

Publications and source records attributed to S Tufik.

At least 91 records · Page 5Linked to original sources

PubMed1998

Neuroethologic differences in sleep deprivation induced by the single- and multiple-platform methods.

It has been proposed that the multiple-platform method (MP) for desynchronized sleep (DS) deprivation eliminates the stress induced by social isolation and by the restriction of locomotion in the single-platform (SP) method. MP, however, induces a higher increase in plasma corticosterone and ACTH levels than SP. Since deprivation is of heuristic value to identify the functional role of this state of sleep, the objective of the present study was to determine the behavioral differences exhibited by rats during sleep deprivation induced by these two methods. All behavioral patterns exhibited by a group of 7 albino male Wistar rats submitted to 4 days of sleep deprivation by the MP method (15 platforms, spaced 150 mm apart) and by 7 other rats submitted to sleep deprivation by the SP method were recorded in order to elaborate an ethogram. The behavioral patterns were quantitated in 10 replications by naive observers using other groups of 7 rats each submitted to the same deprivation schedule. Each quantification session lasted 35 min and the behavioral patterns presented by each rat over a period of 5 min were counted. The results obtained were: a) rats submitted to the MP method changed platforms at a mean rate of 2.62 +/- 1.17 platforms h-1 animal-1; b) the number of episodes of noninteractive waking patterns for the MP animals was significantly higher than that for SP animals (1077 vs 768); c) additional episodes of waking patterns (26.9 +/- 18.9 episodes/session) were promoted by social interaction in MP animals; d) the cumulative number of sleep episodes observed in the MP test (311) was significantly lower (chi-square test, 1 d.f., P < 0.05) than that observed in the SP test (534); e) rats submitted to the MP test did not show the well-known increase in ambulatory activity observed after the end of the SP test; f) comparison of 6 MP and 6 SP rats showed a significantly shorter latency to the onset of DS in MP rats (7.8 +/- 4.3 and 29.0 +/- 25.0 min, respectively; Student t-test, P < 0.05). We conclude that the social interaction occurring in the MP test generates additional stress since it increases the time of forced wakefulness and reduces the time of rest promoted by synchronized sleep.

Adrenocorticotropic Hormone↗

PubMed1997

Absence of oxidative stress following paradoxical sleep deprivation in rats.

Paradoxical sleep deprivation was performed on rats using platform technique to investigate the oxidative process associated with it. Levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), total glutathione (GSH) and malondialdehyde production were measured in brain of rats under control conditions (C) and those on single large platforms (SLP), multiple large platforms (MLP), single small platforms (SSP) and multiple small platforms (MSP) groups. SOD, CAT and GPx brain activity and malondialdehyde production were not modified by any of the procedures. Brain GSH, however, was significantly reduced in both SSP and SLP groups. These results suggest that paradoxical sleep deprivation per se is not associated with oxidative damage. The observed alterations could be attributed to factors such as immobilization and social isolation present in the single platform techniques.

Animals↗

PubMed1997

Correlation between K complex, periodic leg movements (PLM), and myoclonus during sleep in paraplegic adults before and after an acute physical activity.

K complex is the characteristic wave of stage II of sleep. The relationship between periodic limb movements (PLM) and the restless legs syndrome (RLS), and the incidence of K complexes and alpha activity has been previously described. The aim of the present study was to evaluate the effect of an acute physical activity upon K complex, PLM, and myoclonus during sleep in individuals who were paraplegic. We evaluated 84 polysomnograms from 28 volunteers with a spinal cord injury at the level of T7-T12, obtained during three consecutive nights. On day 3, the volunteers were submitted to a test of maximum effort (manual cycloergometer, with the equipment Cybex Met 300, with a progressive load increase of 12.5 w, every 2 min). The analysis of the polysomnographic recordings showed a positive correlation between the incidence of K complex and limb movements on nights 1, 2 and 3. Similarly, a correlation between the incidence of K complex and myoclonus was observed on nights 1, 2 and 3. An increased incidence of the total K complex was seen on night 3, 36 h after the test maximum effort. Both total K complex and K complex/h were reduced on night 2, compared to basal recording (night 1). There was a reduction of sleep latency on night 2, whereas total sleeping time increased progressively on night 3, as well as REM phase on nights 2 and 3. These findings indicate that physical activity can effect or modulate the incidence of K complex and suggest that a positive correlation between PLM and K complex may occur in those who are paraplegic from a spinal cord injury. In conclusion, sleep can be consolidated after physical activity.

Adult↗

PubMed1997

Effects of alcohol on sleep parameters of sleep-deprived healthy volunteers.

Both partial and total sleep deprivation frequently result in a rebound of paradoxical sleep (PS), as well as of slow-wave or delta sleep. Acute administration of ethanol inhibits PS in normal volunteers. This effect is dose-dependent and consists of increased latency to and reduced duration of paradoxical sleep. It has also been shown that PS rebound may occur on the same night, as blood alcohol concentration (BAC) declines. The present study examined the effects of sleep deprivation prior to ethanol administration on nocturnal-sleep parameters in healthy male volunteers. Polysomnograms were performed with a randomized, crossover design on baseline, placebo, post-placebo, ethanol (0.9 g/kg), and post-ethanol recovery nights. Subjects were submitted to partial (PSD) (n = 6) or total (TSD) (n = 6) sleep deprivation for 40 hours before placebo or ethanol conditions. Results evidenced a PS inhibition after ethanol treatment in both deprivation groups, despite their sleep debt (PSD, placebo = 103.7 minutes and ethanol = 72.7 minutes; TSD, placebo = 111.8 minutes and ethanol = 76.6 minutes). This inhibition was BAC-dependent and specific to PS, since delta sleep remained unaltered. These effects could be due to the reduction of cholinergic release and/or glutamatergic inhibition, both of which modulate acetylcholine release.

Adult↗

PubMed1997

Long-term effects of maternal deprivation on the corticosterone response to stress in rats.

Twenty-four hours of maternal deprivation result in activation of the infant rat's adrenocortical axis. In the present study we examined the long-term effects of maternal deprivation on the corticosterone (Cort) response to stress. Pups were maternally deprived (Dep) on postnatal day (PND) 11 and tested immediately (PND 12) or returned to their mothers and tested at later ages. Testing consisted of a time course of the Cort response to a saline injection (5, 15, 30, and 60 min). At PND 12, the response of Dep pups was higher than that of nondeprived (non-Dep) pups. No group differences were observed at PND 16 and 22. On PND 30, Dep rats showed lower Cort levels than non-Dep pups at 0, 5, and 30 min after saline. At PND 60, non-Dep females showed higher Cort levels than males at 5, 15, and 30 min. This gender difference for Dep pups was observed only at 5 min. Male and female Dep animals presented lower Cort levels than non-Dep counterparts at 60 and 30 min after saline, respectively. These findings indicate that maternal deprivation effects on Cort secretion are long lasting. Dep rats showed a smaller adrenal response to stress at PND 30, whereas as adults the stress response was similar but the turnoff was different.

Aging↗

PubMed1997

Juvenile fibromyalgia: clinical and polysomnographic aspects.

OBJECTIVE: To identify the child-mother diagnostic correlation in fibromyalgia (FM), to study sleep disturbance in juvenile FM, and to compare clinical aspects and sleep disorders between these groups. METHODS: We studied 34 children with confirmed FM aged 11 +/- 1 years, 10 children with diffuse pain, and 17 age and sex matched asymptomatic controls. The respective 61 mothers were included: 34 asymptomatic and 27 with FM. All participants were subjected to clinical evaluation, a sleep questionnaire, and nocturnal polysomnography, preceded by a night of adaptation. Sleep scoring was done visually and a computerized analysis was performed for alpha, theta, and delta waves in slow wave sleep (SWS). RESULTS: A significant predominance of mothers with FM was observed in the group of children with FM (71%) compared to children with diffuse pain (30%) and asymptomatic children (0%). According to the sleep questionnaire, the complaints of superficial sleep and nonrestorative sleep were more prominent in mothers with FM than in children with FM, whereas motor agitation during sleep was more frequent in the children with FM. Polysomnographic anomalies were also more prominent in mothers with FM than in children with FM in terms of decrease in sleep efficiency, increase of number of arousals during sleep, and alpha intrusion in SWS. Both FM groups presented an increased alpha + theta time/delta time index during SWS compared to respective controls, and mothers with FM also showed an increase in alpha time/delta time index during SWS, compared to asymptomatic mothers. A correlation was found between alpha + theta time/delta time index during SWS and intensity of clinical manifestations of pain and sleep anomalies in children and their mothers. CONCLUSION: Significant concordance was observed regarding FM diagnosis in children and their mothers. Sleep complaints and polysomnography findings were less prominent in affected children compared to mothers with FM. In addition, we observed a significant correlation between polysomnographic indexes, sleep anomalies, and pain manifestations in children and their mothers.

Adult↗

PubMed1996

Comparative bioavailability study of an once-a-week matrix versus a twice-a-week reservoir transdermal estradiol delivery systems in postmenopausal women.

An open-label, randomised, crossover study was conducted with in healthy postmenopausal women to compare the relative bioavailability of a matrix transdermal estradiol delivery system worn for 7 consecutive days, versus a reservoir transdermal patch worn for 4 days followed by its immediate replacement by another patch worn for further 3 consecutive days. There was a minimum 7-day washout period between the two study periods. Both systems were labelled to release approximately 50 micrograms/day of estradiol. Twenty-six subjects were evaluated with regard to estradiol serum levels. Blood samples were taken immediately before and at regular intervals until 192 h after the initiation of each study treatment (patch application) and assayed for estradiol. There was no difference between the patches with regard to Cmax. Based on the relative bioavailability, one matrix patch proved to be bioequivalent to two reservoir patches worn consecutively for 7 days. These results demonstrate the ability of one matrix patch to deliver consistent therapeutic levels of estradiol over a 7-day period.

Administration, Cutaneous↗

PubMed1996

Incidence of periodic leg movements and of the restless legs syndrome during sleep following acute physical activity in spinal cord injury subjects.

The purpose of the present study was to evaluate sleep patterns and complaints, and Periodic Limb Movement (PLM) and the Restless Legs Syndrome (RLS) in subjects with complete spinal cord injury. Volunteers were submitted to two polysomnograms (Oxford Medilog SAC system--EEG, EMG, EOC): (1) basal night, when the volunteer arrived at the Sleep Center, and (2) after a maximal physical test (Cybex Met 300/increase of 12.5 watts/2 min until exhaustion). Eleven volunteers with complete spinal cord injury between T7-T12 were evaluated. Data were analyzed by the paired Student's test (total sleeping time) and by the Wilcoxon matched paired test (change of sleep states, number of awakenings during sleep, latency to REM sleep and leg movements--PLM + RLS). Comparison of sleep recordings from the night before with that from the night after (12 h) practice of physical activity, showed a significant reduction in all of the sleep parameters. The results indicate that physical activity improves the sleep patterns of spinal cord injured volunteers. In particular, we noticed that PLM and RLS after physical activity were inhibited during sleep.

Adult↗

PubMed1995

Paradoxical sleep deprivation in female rats alters drug-induced behaviors.

Paradoxical sleep deprivation (PSD) induces changes in behaviors induced by dopaminergic and cholinergic agonists, including increased aggressive behavior and stereotypy, decreased number of yawns, and shedding of bloody tears in male rats. In female rats, however, very little is known about the relationship between PSD and the effect of these drugs. The present study sought to examine this issue. As in males, PSD in females resulted in increased apomorphine-induced stereotypy, decreased pilocarpine-induced chromodacryorrhea, and hyperthermia. Unlike males, however, no apomorphine-induced aggressiveness or apomorphine- and pilocarpine-induced yawning were observed in PSD females. These findings suggest that female sexual hormones may affect the expression of some behaviors and not the neurotransmission as a whole, because drug-induced behaviors in PSD females were partly similar to those observed in PSD males.

Aggression↗

PubMed1995

Effects of stress on drug-induced yawning: constant vs. intermittent stress.

Effects of stress on drug-induced yawning: Constant vs. intermittent stress. PHYSIOL BEHAV 58(1) 181-184, 1995.--Experiment 1 tested whether chronic exposure to immobilization, foot shock or forced swimming would result in suppression of apomorphine-, pilocarpine-, and physostigmine-induced yawning. Immobilization caused suppression of yawning, whereas foot shock and swimming resulted in increased number of yawns. Since interstressor interval was long in the two latter stressors, animals could have recovered and the increase in yawning could be due to the last (acute) exposure to stress. In Experiment 2 we recorded the number of yawns induced by pilocarpine in animals exposed to 1 h of swimming or foot shock. No differences between control and acutely stressed animals were detected. These results suggest that yawning is differently altered by constant and intermittent stressors (i.e., diminished by constant and increased by intermittent stress).

Animals↗

PubMed1995

Atropine increases pilocarpine-induced yawning behavior in paradoxical sleep deprived rats.

Paradoxical sleep (PS) deprivation has been suggested to induce supersensitivity of postsynaptic dopamine (DA) receptors and subsensitivity of acetylcholine (ACh) receptors. Yawning behavior is reduced after PS deprivation and is believed to result from an interaction between ACh and DA systems. Concomitant treatment of PS deprived animals with DA agonists reverses PS deprivation effects on stereotypy and aggressiveness. To examine this possibility on yawning behavior, rats were treated, during the deprivation period, with atropine, methamphetamine, haloperidol or distilled water. Following PS deprivation, rats were injected with apomorphine or pilocarpine and number of yawns was recorded. Atropine increased yawning of PS deprived rats induced by pilocarpine, but not by apomorphine. Treatment with methamphetamine and haloperidol did not change PS deprivation effect on pilocarpine- and apomorphine-induced yawning. The data suggest that reversal of PS deprivation-induced yawning inhibition is mediated distinctly by both acetylcholine and dopamine systems.

Animals↗

PubMed1994

Decreased muscarinic receptor binding in rat brain after paradoxical sleep deprivation: an autoradiographic study.

Previous work demonstrated that paradoxical sleep deprivation (PSD) leads to a decrease in yawning behavior elicited by cholinergic agonists, suggesting that a downregulation of cholinergic muscarinic receptors may occur after PSD. More recent work using intracerebral injections of muscarinic agonists has suggested a critical role for M2 receptors in paradoxical sleep. In this study [3H]AF-DX 384 was used to investigate the effects of PSD on M2-type cholinergic receptors throughout the brain using quantitative autoradiography. After 96 h of paradoxical sleep deprivation, [3H]AF-DX 384 binding was generally reduced throughout the brain, and significantly so in the olfactory tubercle (-20%), n. accumbens (-23%), frontal caudate-putamen (-16%), islands of Callejas (-20%), piriform cortex (-24%), lateral (-26%) and medial (-24%) septum, anteromedial (-19%), ventrolateral (-22%), and lateral geniculate (-15%) nuclei of thalamus, deep layers of the superior colliculus (-15%), entorhinal cortex (-12%) and subiculum (-23%). [3H]AF-DX 384 binding was reduced in pontine structures, but not to a higher degree than in other brain areas. The observed downregulation of M2-type muscarinic receptors after PSD may be causally related to the previously reported decrease in cholinergically induced behaviors after PSD.

Animals↗

PubMed1994

Dissociated paradoxical sleep deprivation effects on inhibitory avoidance and conditioned fear.

Rats were submitted to paradoxical sleep deprivation (PSD) for 24, 72, or 96 h and were trained on a double aversively motivated task, encompassing a step-through inhibitory avoidance and a classical conditioning of fear to a brief tone serving as conditional stimulus. Retention test of the inhibitory avoidance was performed at the same apparatus of training (without tone presentation). Retention of conditioned fear was assessed in an open field apparatus, where the freezing reaction to the tone was measured. PSD for 24 and 72 h preceding the training session had no effect on either task. However, PSD during the 96 h preceding the training session impaired acquisition of inhibitory avoidance, but had no effect on classically conditioned fear. It is concluded that PSD had differential effects on the two tasks, both aversively motivated and trained at the same time and conditions.

Acoustic Stimulation↗

PubMed1994

Autoradiographic analysis of D1 and D2 dopaminergic receptors in rat brain after paradoxical sleep deprivation.

Previous work had shown that paradoxical sleep deprivation (PSD) results in potentiation of several apomorphine-induced behaviors, leading to the suggestion that PSD induces an upregulation of brain dopamine receptors. In this study, quantitative receptor autoradiography was used to verify whether PSD does, in fact, induce alterations in D1 or D2 receptor binding, and to investigate the regional brain specificity of such effects. After 96 h of PSD, [3H]SCH-23390 binding to D1 receptors was examined in 30 different brain areas of 10 experimental and 10 cage control rats. [3H]Spiperone was used to label D2 sites in adjacent tissue sections. Results revealed a 39% increase in [3H]SCH-23390 binding in the entorhinal cortex of PSD rats (p < 0.05), but no other changes in any of the remaining 29 brain areas examined. In contrast, [3H]spiperone binding was significantly elevated in the n. accumbens (+45%) and in all subregions of the caudate-putamen (range: +13% to +23%). These results, thus, provide evidence that PSD increases D2 but not D1 receptor binding in brain. The present results also suggest that upregulated D2 receptors can account for the previously reported changes in apomorphine-induced behaviors after PSD.

Animals↗

PubMed1994

Effects of a prolonged administration of valepotriates in rats on the mothers and their offspring.

Valeriana officinalis L. (Valerianaceae) is widely known to be associated with sedative properties. The effects of a valepotriates mixtures on mothers and progeny were evaluated in rats. A 30-day administration of valepotriates did not change the average length of estral cycle, nor the number of estrous phases during this period. Also, there were no changes on the fertility index. Fetotoxicity and external examination studies did not show differences, although internal examination revealed an increase in number of retarded ossification after the highest doses employed--12 and 24 mg/kg. No changes were detected in the development of the offspring after treatment during pregnancy. As for temperature, valepotriates caused a hypothermizant effect after administration by the intraperitoneal route but not after oral administration. Generally, the valepotriates employed induced some alterations after administration by the intraperitoneal route, but doses given orally were innocuous to pregnant rats and their offspring.

Administration, Oral↗

PubMed1993

Sodium diclofenac inhibits hyperthermia induced by paradoxical sleep deprivation: the possible participation of prostaglandins.

Sodium diclofenac inhibits hyperthermia induced by paradoxical sleep deprivation (PSD), which suggests the participation of prostaglandins. The temperature of paradoxical sleep-deprived rats increased from the first to the fourth day of deprivation. This hyperthermia was blocked on the second, third, and fourth days by daily administration, twice a day, of 10 mg/kg of sodium diclofenac, a potent prostaglandin synthesis inhibitor. In the dose of 10 mg/kg, a decrease of temperature was observed only on the second and third days of PSD. These data suggest the participation of prostaglandins in modulating the increase in temperature during PSD.

Animals↗

PubMed1991

Effects of selective adrenoceptor agonists and antagonists on aggressive behavior elicited by apomorphine, DL-dopa and fusaric acid in REM-sleep-deprived rats.

REM sleep deprivation (REMSD) results in behavioral changes such as the appearance of affective aggression induced by apomorphine (APO) and other dopaminergic agents. REMSD modifies dopamine-mediated behavior as well as the adrenergic receptor sensitivity. This paper evaluates the interaction between these two neurotransmission systems through changes in APO-, DL-DOPA- and fusaric acid (FA)-induced aggressive behavior in REMSD rats pretreated with phentolamine, propranolol, metaraminol, prazosin, clonidine, yohimbine, isoproterenol, butoxamine and maprotiline. Only isoproterenol reduced FA-induced aggressiveness. No specific changes in aggressiveness were noticed with other treatments and not even inhibitors of norepinephrine transmission induced aggressive behavior. It is concluded that norepinephrine had a slight inhibitory action on aggressiveness elicited by dopaminomimetic agents in REMSD rats. Beta-adrenoceptors could be responsible for this effect since only beta-selective drugs reduced aggression. As REMSD reduces beta-adrenoceptor sensitivity, only minor changes in aggressiveness could be observed. It was noted that the three drugs used to induce aggressive behavior elicited different patterns of aggression.

Aggression↗

PubMed1990

Effects of REM sleep deprivation of ACTH-induced yawning.

Central administration of ACTH in rats induces yawning and stretching. In order to study the effects of REM sleep deprivation on ACTH-induced yawning, the peptide was injected immediately after the REM sleep deprivation period or 24 h later. REM sleep deprivation impaired ACTH-induced yawning, but after a 24-hour recovery period, rats displayed a number of yawns similar to those in control animals. Implications for an involvement of dopaminergic and mainly cholinergic systems are discussed.

Adrenocorticotropic Hormone↗