The rat suprachiasmatic nucleus is a clock for all seasons.
AUTOR(ES)
Sumová, A
RESUMO
Seasonal changes of daylength (photoperiod) affect the expression of hormonal and behavioral circadian rhythms in a variety of organisms. In mammals, such effects might reflect photoperiodic changes in the circadian pace-making system [located in the suprachiasmatic nucleus (SCN) of the hypothalamus] that governs these rhythms, but to date no functionally relevant, intrinsic property of the SCN has been shown to be photoperiod dependent. We have analyzed the temporal regulation of light-induced c-fos gene expression in the SCN of rats maintained in long or short photoperiods. Both in situ hybridization and immunohistochemical assays show that the endogenous circadian rhythm of light responsiveness in the SCN is altered by photoperiod, with the duration of the photosensitive subjective night under the short photoperiod 5-6 h longer than under the long photoperiod. Our results provide evidence that a functional property of the SCN is altered by photoperiod and suggest that the nucleus is involved in photoperiodic time measurement.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=41224Documentos Relacionados
- Insight into molecular core clock mechanism of embryonic and early postnatal rat suprachiasmatic nucleus
- An ultrastructural study of the rat's suprachiasmatic nucleus.
- Neurones in the supraoptic nucleus of the rat are regulated by a projection from the suprachiasmatic nucleus.
- Two distinct oscillators in the rat suprachiasmatic nucleus in vitro.
- Calcium signaling: A tale for all seasons
