5-HT(1A) autoreceptor antagonist-induced 5-HT release in the hamster suprachiasmatic nuclei: effects on circadian clock resetting.
Serotonin (5-HT) has been implicated in phase shifting of mammalian circadian rhythms by non-photic stimuli. This study tests whether pharmacological induction of endogenous 5-HT release can shift circadian phase in the Syrian hamster. Systemic injections of the 5-HT(1A) antagonist WAY100635 during the mid-subjective day significantly increased 5-HT in dialysate from the hamster suprachiasmatic nucleus (SCN) circadian pacemaker by approximately 50% for 40-60 min. However, this was not associated with phase shifts or with potentiation of phase shifts induced by a 3 h bout of running. These results indicate that enhanced 5-HT release in the SCN or possibly other regions is not sufficient to induce phase shifts in the subjective day.
Antle
M C
MC
Department of Psychology, Simon Fraser University, Burnaby, Canada.
Glass
J D
JD
Mistlberger
R E
RE
D000818:Animals; D017660:Autoreceptors / Q000037:antagonists & inhibitors* / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D006224:Cricetinae; D008647:Mesocricetus; D017551:Microdialysis; D005082:Physical Exertion; D010879:Piperazines / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D011985:Receptors, Serotonin / Q000187:drug effects* / Q000502:physiology; D044263:Receptors, Serotonin, 5-HT1; D012701:Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology*; D013493:Suprachiasmatic Nucleus / Q000187:drug effects / Q000378:metabolism*
D017660:Autoreceptors; D010879:Piperazines; D011725:Pyridines; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D012702:Serotonin Antagonists; D012701:Serotonin; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide