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Lability and diversity of circadian rhythms of cotton rats Sigmodon hispidus

Lability and diversity of circadian rhythms of cotton rats Sigmodon hispidus IRVING ZUCKER University of Cctlifornia, Berkeley, California IJo~~~~~~, PHYLLIS G., IRVING ZUCKER, LabiliLy diversity of circadian rhythms of cotton rats Sigmodon hispidus. Am. J. Physiol. 244 (Regulatory Integrative Comp. Physiol. 13): R338-R346, 1983.-Cotton rats (Sigmodon hispidus) were maintained from birth in constant LD 14:10 photoperiods temperatures. Wheel running was diurnal for 6 of 13 juvenile rats nocturnal for most others. Most diurnal rats eventually added nocturnal activity components. In constant darkness the activity rhythms of adult rats free-ran with a period of 23.2 k 0.3 h; in constant illumination the period was 24.7 k 0.1 h, in conformation to Aschoffs rule for nocturnal rodents. Some previously nocturnal adult rats eventually adopted stable diurnal activity cycles other were successively nocturnal, diurnal for 6 mo, then nocturnal again while maintained in the LD 14:lO photoperiod. The existence of multiple activity types, as well as the spontaneous inversions from nocturnal to diurnal status substantiate extend field observations of this species, Seasonal inversions from nocturnal to diurnal activity, previously attributed to fluctuating environmental conditions, may also be subject to regulation by endogenous processes. It is suggested that spontaneous phase reversals in activity reflect changes in entrainment of circadian pacemakers by the lightdark http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png AJP - Regulatory, Integrative and Comparative Physiology The American Physiological Society

Lability and diversity of circadian rhythms of cotton rats Sigmodon hispidus

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Publisher
The American Physiological Society
Copyright
Copyright © 1983 the American Physiological Society
ISSN
0363-6119
eISSN
1522-1490
Publisher site
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Abstract

IRVING ZUCKER University of Cctlifornia, Berkeley, California IJo~~~~~~, PHYLLIS G., IRVING ZUCKER, LabiliLy diversity of circadian rhythms of cotton rats Sigmodon hispidus. Am. J. Physiol. 244 (Regulatory Integrative Comp. Physiol. 13): R338-R346, 1983.-Cotton rats (Sigmodon hispidus) were maintained from birth in constant LD 14:10 photoperiods temperatures. Wheel running was diurnal for 6 of 13 juvenile rats nocturnal for most others. Most diurnal rats eventually added nocturnal activity components. In constant darkness the activity rhythms of adult rats free-ran with a period of 23.2 k 0.3 h; in constant illumination the period was 24.7 k 0.1 h, in conformation to Aschoffs rule for nocturnal rodents. Some previously nocturnal adult rats eventually adopted stable diurnal activity cycles other were successively nocturnal, diurnal for 6 mo, then nocturnal again while maintained in the LD 14:lO photoperiod. The existence of multiple activity types, as well as the spontaneous inversions from nocturnal to diurnal status substantiate extend field observations of this species, Seasonal inversions from nocturnal to diurnal activity, previously attributed to fluctuating environmental conditions, may also be subject to regulation by endogenous processes. It is suggested that spontaneous phase reversals in activity reflect changes in entrainment of circadian pacemakers by the lightdark

Journal

AJP - Regulatory, Integrative and Comparative Physiology – The American Physiological Society

Published: Mar 1, 1983

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