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Duration of Melatonin Regulates Seasonal Changes in Song Control Nuclei of the House Sparrow, Passer domesticus: Independence from Gonads and Circadian Entrainment

Duration of Melatonin Regulates Seasonal Changes in Song Control Nuclei of the House Sparrow,... Avian behavior and physiology are temporally regulated by a complex circadian clock on both a daily and an annual basis. The circadian secretion of the hormone melatonin is a critical component of the regulation of circadian/daily processes in passerine birds, but there is little evidence that the gland regulates annual changes in primary reproductive function. Here it is shown that locomotor rhythms of house sparrows, Passer domesticus, which are made arrhythmic by either pinealectomy or maintenance in constant light, can be synchronized by daily administration of melatonin of different durations to simulate the melatonin profiles indicative of long and short photoperiods. Pinealectomized male sparrows maintained in constant darkness were entrained by both melatonin regimens. In both cases, testes were regressed and the song control nuclei were small. Intact male house sparrows maintained in constant light were also entrained to both melatonin regimens. However, sparrows that received a long duration melatonin cycle exhibited small song control nuclei, while sparrows that received short duration melatonin or no melatonin at all exhibited large song control nuclei. The data indicate that seasonal changes in melatonin duration contribute to the regulation of song control nuclei. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Biological Rhythms SAGE

Duration of Melatonin Regulates Seasonal Changes in Song Control Nuclei of the House Sparrow, Passer domesticus: Independence from Gonads and Circadian Entrainment

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References (41)

Publisher
SAGE
Copyright
Copyright © by SAGE Publications
ISSN
0748-7304
eISSN
1552-4531
DOI
10.1177/0748730407311110
pmid
18258757
Publisher site
See Article on Publisher Site

Abstract

Avian behavior and physiology are temporally regulated by a complex circadian clock on both a daily and an annual basis. The circadian secretion of the hormone melatonin is a critical component of the regulation of circadian/daily processes in passerine birds, but there is little evidence that the gland regulates annual changes in primary reproductive function. Here it is shown that locomotor rhythms of house sparrows, Passer domesticus, which are made arrhythmic by either pinealectomy or maintenance in constant light, can be synchronized by daily administration of melatonin of different durations to simulate the melatonin profiles indicative of long and short photoperiods. Pinealectomized male sparrows maintained in constant darkness were entrained by both melatonin regimens. In both cases, testes were regressed and the song control nuclei were small. Intact male house sparrows maintained in constant light were also entrained to both melatonin regimens. However, sparrows that received a long duration melatonin cycle exhibited small song control nuclei, while sparrows that received short duration melatonin or no melatonin at all exhibited large song control nuclei. The data indicate that seasonal changes in melatonin duration contribute to the regulation of song control nuclei.

Journal

Journal of Biological Rhythms – SAGE

Published: Feb 1, 2008

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