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Biomedical subjects

J Danguir

Publications and source records attributed to J Danguir.

32 records · Page 2Linked to original sources
PubMed1982

LCEC monitoring of 5-hydroxyindolic compounds in the cerebrospinal fluid of the rat related to sleep and feeding.

A new technique which allows for both the chronic withdrawal of CSF and continuous recording of EEG sleep patterns and food intake in the freely moving rat is described. Liquid chromatography with electrochemical detection (LCEC) was used for the direct assay of tryptophan metabolites in the CSF. Both 5-hydroxyindolacetic acid (5-HIAA) and 5-hydroxytryptophan (5-HTP) were easily detectable. However, serotonin (5-HT) levels were relatively low and 5-hydroxytryptophol (5-HTPhol) and N-methylserotonin (N-Me-5HT) were undetectable in several cases. The continuous monitoring of 5-HIAA and 5-HTP indicated stable values throughout the 3-hr experiments during which no food or small meals were consumed. In the rat which consumed a large meal, both 5-HIAA and 5-HTP significantly increased following that meal. This increase in metabolites may be the result of an increased availability of tryptophan to the brain as a result of the meal. Although this study is preliminary, the described technique can provide further information about the possible relationship between behavioral (sleep and/or feeding) changes and the concomitant neurochemical fluctuations.

5-Hydroxytryptophan↗
PubMed1980

Cortical activity and sleep in the rat lateral hypothalamic syndrome.

Continuous EEG recordings were performed in lateral hypothalamic (LH) damaged rats from day 1 post-lesion when totally aphagic and adipsic until complete recovery of their feeding and drinking. During the early post-operative stage (days 1--3 post-lesion), LH rats showed a complete disorganization of their basal EEG which was characterized by two superimposed activities, a constant rapid low voltage activity modulated by high voltage low frequency waves. Except in the case of intense illumination, several arousing stimuli did not affect this activity. By day 4 post-lesion, the two overlapping activities were replaced by less abnormal waves on top of which the first normal sleep spindles appeared. Sleep increased gradually and normal amounts of both slow-wave and paradoxical sleep were observed during 'stage 4' of recovery when rats again ate food and drank water. During this stage, and contrary to normal rats, meal size was correlated only with sleep events occurring within the intermeal interval following the next meal, when most of the ingested nutrients reached the systemic compartment. The effect of sleep of intragastric or intravenous caloric repletion was, at least in part, in agreement with the view of indirect effect of LH lesions on sleep through metabolic impairment. Whatever the mechanism underlying sleep deficits, these are one of the major symptoms of the lateral hypothalamic syndrome.

Animals↗
PubMed1980

Circadian sleep and feeding patterns in the rat: possible dependence on lipogenesis and lipolysis.

Sleep and feeding patterns were continuously recorded in rats under intravenous saline (control) and alternating insulin-epinephrine (experimental) infusions. The infusion of insulin (lipogenetic hormone) during the normally light period (0800-1600) replaced by epinephrine (lipolytic hormone) during the normally lipogenetic dark period (1600-0800) resulted in a complete inversion of the normal circadian distribution of sleep and feeding patterns and also of their correlation. Insulin infusion resulted in low blood glucose and glycerol levels whereas epinephrine increased these physiological parameters. Different control conditions showed that the fluctuations of sleep and feeding were dependent on the rate of utilization of the circulating metabolites at the cellular level. These results together with previous data suggest that the relation between sleep and feeding and their concomitant circadian fluctuation are possibly modulated by a common factor, namely the metabolic rate that is influenced by the lipogenesis/lipolysis rate.

Animals↗
PubMed1980

Intravenous infusions of nutrients and sleep in the rat: an ischymetric sleep regulation hypothesis.

Unrestrained food-deprived rats received their daily caloric needs through continuous or discontinuous intravenous infusions of specific nutritive substances over a period of 3 consecutive days each, and the effect on sleep monitored by electroencephalogram was examined. Continuous glucose or lipid infusions did not affect the daily sleep quotas. Amino-acid infusion brought about a significant increase in paradoxical sleep (PS), whereas slow-wave sleep (SWS) remained unchanged. Rats that received the highly nutritive composite solution showed significant increase in both SWS and PS. The same increase in SWS and PS was observed when exogenous insulin was coinfused with continuous infusion of glucose or when glucose infusions were discontinuous. These findings suggest that sleep might be related to both the nature and the degree of utilization of the circulating metabolites. A model for the action on sleep of nutrients at the systemic level was proposed; only when substances are metabolized is there a direct effect on sleep mechanisms.

Amino Acids↗
PubMed1976

Effects of lithium chloride on sleep patterns in the rat.

Continuous EEG recordings were performed in rats both after saline injections (control days) and after LiCl treatments. LiCl administration was always followed by an initial period of general distress and sleep inhibition during 2 to 3 hr after low toxic doses (1.5 mEq/kg) and a much more longer period (10 hr) after high toxic doses (3 mEq/kg). Once this state was overcome, the pharmacological effect of lithimia seems to potentiate sleep and particularly paradoxical sleep (PS). It appears that this potentiation of PS occurs once lithimia reaches levels used in human therapeutics.

Animals↗
PubMed1975

[Protection of a naive rat from consuming a solution by a congeneric rat which has learned to refuse it].

When a rat drinks a solution of lithium chloride, it learns once and for all to refuse solutions of similar (salty) taste. In the presence of a naive rat, rats treated with lithium chloride develop an "eviction" behaviour which makes them push the naive rat away from the saline. The result is a "protection" of the naive rat, made apparent from a fall in the consumption of the solution offered.

Animals↗
PubMedDate not supplied

Food intake in rats is increased by intracerebroventricular infusion of the somatostatin analogue SMS 201-995 and is decreased by somatostatin antiserum.

The chronic intracerebroventricular infusion of the somatostatin analogue SMS 201-995 resulted in a significant increase in daily food intake which was accompanied by an unexpected body weight loss. The neutralisation of central somatostatin using a specific somatostatin antiserum resulted in a significant decrease in daily food intake. These results suggest that endogenous somatostatin in the brain can drive feeding behavior and alter body weight.

Animals↗
PubMedDate not supplied

The somatostatin analogue SMS 201-995 promotes paradoxical sleep in aged rats.

Sleep patterns were recorded in aged rats (800- to 840-day-old) under control conditions and following either intraperitoneal injections of three different doses of the octapeptide somatostatin analogue SMS 201-995 (SMS) or after spontaneous oral intake of SMS-containing water (0.003 mg/ml). The intraperitoneal administration of SMS resulted in a dose-dependent and selective increase of paradoxical sleep (SP). Similarly, the spontaneous oral ingestion of SMS induced a significant increase of the daily duration of PS. Slow wave sleep remained unchanged in both cases. These findings confirm previous results demonstrating a role of somatostatin in the generation of PS. In addition, they suggest that sleep deficits during aging may be the consequence of decreased age-related somatostatin release.

Administration, Oral↗
PubMedDate not supplied

Sleep deficits in rats with hereditary diabetes insipidus.

Interest in the Brattleboro diabetes insipidus rat has resurged with the recent increase in research on brain peptides. Various reports have suggested that in these rats, the impaired ability for memory consolidation is due essentially to a chronic lack of vasopressin. On the other hand, sleep stages and particularly the paradoxical phase of sleep have been shown to have a key role in the processes of learning and memory consolidation. Curiously, the possible involvement of sleep deficits in the impairment of memory function in the Brattleboro rat has never been suspected. Here I report a significant reduction (38%) in the daily duration of paradoxical sleep (PS) in the homozygous diabetes insipidus (HODI) rat compared to the heterozygous Long Evans strain. Normal or increased durations of PS were observed after intravenous (i.v.) administration of vasopressin but also when the normal daily water intake (240 ml) was infused i.v. These results provide direct evidence that PS deficits in the HODI rat are not due to the absence of vasopressin. They also suggest that the impaired ability for learning and memory processes are probably due to the impairment of PS rather than to some direct consequence of the hereditary lack of vasopressin.

Animals↗