Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Autoreceptors / antagonists & inhibitors*
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Autoreceptors / physiology
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Circadian Rhythm / physiology*
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Cricetinae
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Mesocricetus
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Microdialysis
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Physical Exertion
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Piperazines / pharmacology*
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Pyridines / pharmacology*
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Receptors, Serotonin / drug effects*
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Receptors, Serotonin / physiology
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Receptors, Serotonin, 5-HT1
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Serotonin / metabolism*
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Serotonin Antagonists / pharmacology*
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Suprachiasmatic Nucleus / drug effects
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Suprachiasmatic Nucleus / metabolism*
Substances
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Autoreceptors
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Piperazines
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Pyridines
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Receptors, Serotonin
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Receptors, Serotonin, 5-HT1
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Serotonin Antagonists
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Serotonin
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N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide