Abstract
In order to elucidate whether a circannual rhythm exists in the function of the central serotonin (5-HT) system, we examined the responsiveness of rats to a selective 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), at different hours of the day in different seasons. The results indicate that both a circadian rhythm and a circannual rhythm exist in the responsiveness. The phases of the circadian rhythm exhibit 1-year period variations, while those of the circannual rhythm exhibit 1-day period variations. These results will help to clarify the disparities among the reports on circadian and circannual rhythms in the phenomenon related to the central 5-HT system.
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Received: 21 April 1997/Final version: 22 July 1997
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Nagayama, H., Lu, JQ. Circadian and circannual rhythms in the function of central 5-HT1A receptors in laboratory rats. Psychopharmacology 135, 279–283 (1998). https://doi.org/10.1007/s002130050510
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DOI: https://doi.org/10.1007/s002130050510