Glucocorticoid-mediated nycthemeral and photoperiodic regulation of tph2 expression |
| |
Authors: | Nexon Laurent Sage Dominique Pévet Paul Raison Sylvie |
| |
Institution: | Département de Neu\robiologie des Rythmes, Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR-3212, 5 rue Blaise Pascal, 67084 Strasbourg, France. |
| |
Abstract: | In the Syrian hamster dorsal and median raphé nuclei, the tryptophan hydroxylase 2 gene (tph2), which codes the rate-limiting enzyme of serotonin synthesis, displays daily variations in its expression in animals entrained to a long but not to a short photoperiod. The present study aimed to assess the role of glucocorticoids in the nycthemeral and photoperiodic regulation of daily tph2 expression. In hamsters held in long photoperiod from birth, after adrenalectomy and glucocorticoid implants the suppression of glucocorticoid rhythms induced an abolition of the daily variations in tph2-mRNA concentrations, a decrease in the amplitude of body temperature rhythms and an increase in testosterone levels. All these effects were reversed after experimental restoration of a clear daily rhythm in the plasma glucocorticoid concentrations. We conclude that the photoperiod-dependent rhythm of glucocorticoids is the main regulator of tph2 daily expression. |
| |
Keywords: | body temperature rhythm Syrian hamster testosterone tryptophan hydroxylase |
本文献已被 PubMed 等数据库收录! |
|