[Genetic study of paradoxical sleep in mice. Connection with coloration genes]

The study of Paradoxical Sleep (PS) from 94 male mice belonging to five inbred strains: C57BR/cdOrl (BR), BALB/cOrl (C), AKROrl, A/JOrl (A/J) and C57BL/6-c2J (B6-c2J), reciprocal F1 hybrids between BR and C strains and backcrosses between F1 hybrids and BR or C was carried out. The results showed that 1) night PS duration was independent from that of day PS; 2) C type of PS seemed to be dominant over BR type; 3) C type is linked to the albino gene; and 4) the albino gene, per se, is not involved in PS regulation. From these results a two locus model was elaborated. This model explains most of the results. The nature of such a genetic support was discussed

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 SWS period was 24 h 8 +/- 6 min and the acrophase occurred at 15:44 +/- 1.35, while for PS, the period was more stable than during LD (24 h 10 +/- 8 min vs. 24 h 55 +/- 43 min) and the acrophase occurred at 16:44 +/- 1:54. Under LL conditions, circadian sleep rhythms persisted during the first 3 days, then completely disappeared during the third week, to be replaced by ultradian rhythms (period of 4-6 h). Time-series analysis showed that the two sleep states became synchronous as early as the second day under constant conditions; the total amount of PS was increased under both conditions (LL and DD) at the expense of duration of waking. Under LD and constant conditions, the pattern of changes in cerebral temperature was similar to that for wakefulness (W). Sulfatoxymelatonin was rhythmically secreted under both LD and DD conditions, whereas, under LL conditions, its rhythm was abolished. the results show that, in IPL rats in the absence of a zeitgeber, the PS and SWS rhythms recover a synchronous phase relationship and PS amounts are increased. (C) 1999 Elsevier Science B.V. All rights reserved.Univ Lyon 1, INSERM, U480, F-69373 Lyon 08, FranceCtr Med Nucl, Serv Radiopharm & Radioanalyse, F-69394 Lyon, FranceUniversidade Federal de São Paulo, EPM, Dept Psicobiol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, EPM, Dept Psicobiol, BR-04023062 São Paulo, BrazilWeb of Scienc