ISSN:
1420-9071
Keywords:
Melatonin
;
circadian rhythms
;
metabolic rate
;
re-entrainment
;
birds
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract Administration of melatonin in the drinking water (200 μg/ml in 1% ethanol) decreased the time of re-entrainment of the circadian rhythm of the metabolic rate (measured as oxygen uptake) of domestic canaries (Serinus canaria) after 10-h delay phase shifts of the light-dark (LD) cycle by 1.3 days on average. Associated with faster re-entrainment, the amplitude of the metabolic rhythm was attenuated by 46% on, average on the first day after the shift as compared with about 25% in the controls. After re-entrainment, the amplitude of the metabolic rhythm during melatonin administration was about 23% lower than in the controls. The minimum resting metabolic rate increased by ca 5% on average during treatment with melatonin. The results are consistent with the hypothesis that constant high plasma levels of melatonin act on higher levels of the circadian oscillatory system rather than by directly affecting peripheral or central photoreceptors.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01925577
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