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Article Dans Une Revue Neuropharmacology Année : 2007

5-HT3 receptor-mediated photic-like responses of the circadian clock in the rat.

Résumé

Serotonin (5-HT) and 5-HT agonists have various resetting effects on the master clock, located in the suprachiasmatic nucleus (SCN), depending on the species. In rats, they induce photic-like effects on both locomotor activity rhythms and gene expression in the SCN. The 5 HT receptor(s) mediating these effects at circadian time 22 are localized in the SCN, most likely at a presynaptic level, on the retinohypothalamic terminals (RHT) known to convey photic information by releasing glutamate. Indeed, RHT degeneration blocks photic-like effects of a non-specific 5 HT agonist, quipazine. However, the 5-HT receptor subtype(s) involved is still unknown, although 5-HT3 receptor activation is known to induce glutamate release. We thus analyzed the effects of selective 5 HT3 agonist and antagonist, as well as a specific NMDA receptor antagonist, on different parameters of the clock. This study shows that the 5-HT3 receptor mediates the resetting effects of quipazine on locomotor activity rhythms. The 5-HT3 receptor is only partially implicated in quipazine-induced expression of c-FOS, while NMDA receptor inhibition blocks quipazine photic-like effects on both parameters. Taken together, photic-like responses produced by 5-HT stimulation in rats are likely mediated by (presynaptic ?) 5-HT3 receptor activation followed by NMDA receptor activation.
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Dates et versions

hal-00097720 , version 1 (22-09-2006)

Identifiants

  • HAL Id : hal-00097720 , version 1

Citer

Caroline Graff, Etienne Challet, Paul Pevet, Franziska Wollnik. 5-HT3 receptor-mediated photic-like responses of the circadian clock in the rat.. Neuropharmacology, 2007, 52, pp.662-671. ⟨hal-00097720⟩

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