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Varying photoperiod in the laboratory rat: profound effect on 24-h sleep pattern but no effect on sleep homeostasis
Journal article

Varying photoperiod in the laboratory rat: profound effect on 24-h sleep pattern but no effect on sleep homeostasis

  • Franken, P. Institute of Pharmacology, University of Zurich, Switzerland.
  • Tobler, I. Institute of Pharmacology, University of Zurich, Switzerland.
  • Borbely, A. A. Institute of Pharmacology, University of Zurich, Switzerland.
Published in:
  • American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. - American Physiological Society. - 1995, vol. 269, no. 3, p. R691-R701
English To assess the influence of the photoperiod on sleep regulation, laboratory rats were adapted to a long photoperiod (LPP; 16:8-h light-dark cycle, LD 16:8) or a short photoperiod (SPP; LD 8:16). The electroencephalogram (EEG) and cortical temperature (TCRT) were continuously recorded for a baseline day, a 24-h sleep deprivation (SD) period, and a recovery day. Data obtained previously for LD 12:12 served for comparison. Whereas the photoperiod exerted a prominent effect on the 24-h sleep pattern, the 24-h baseline level of sleep and the response to SD were little affected. Recovery from SD was characterized by a marked rise in rapid eye movement sleep, a moderate rise in non-rapid eye movement sleep, and an initial enhancement of EEG slow-wave activity followed by a decrease below baseline. The amplitude and phase of the "unmasked" 24-h component of TCRT did not differ between LPP and SPP. Computer simulations demonstrated that the changes of TCRT and EEG slow-wave activity can be largely accounted for by the sequence of the vigilance states. We conclude that the photoperiod does not affect the basic processes underlying sleep regulation.
Language
  • English
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closed
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https://sonar.ch/global/documents/31026
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