title: Effects of ambient light on body temperature regulation in resting and exercising rats.
abstract: We investigated the effects of environmental light and darkness on thermoregulation during both daytime and nighttime by monitoring body temperature (T(b)) and physical activity of rats using a telemetry system. Experiments were performed in both resting and exercising rats. In resting rats, lights-off during the daytime resulted in an increase in both T(b) and activity. Conversely, during the nighttime, T(b) decreased with the lights-on stimulus despite the fact that the activity was left unchanged. Treadmill exercise (10 m/min) always increased T(b) from the basal resting level. In both daytime and nighttime, exercising rats exhibited a persistent T(b)-rise when lights were on. However, in the lights-off condition at nighttime, the T(b) of exercising rats increased to a level significantly higher than that of exercising rats with the lights-on. Our results suggest that light at nighttime causes the suppression of T(b) in both resting and exercising rats.
authors.affiliation: Department of Biology, Tokyo Metropolitan University, Japan. hasehiro@hiroshima-u.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Hasegawa
authors.forename: T
authors.initials: T
authors.lastname: Yazawa
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: M
authors.initials: M
authors.lastname: Yasumatsu
authors.forename: M
authors.initials: M
authors.lastname: Otokawa
authors.forename: Y
authors.initials: Y
authors.lastname: Aihara
mesh_terms: D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology; D003213:Conditioning, Psychological / Q000502:physiology; D003624:Darkness; D008029:Lighting; D008124:Locomotion / Q000502:physiology; D008297:Male; D010775:Photic Stimulation; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012146:Rest / Q000502:physiology*; D013686:Telemetry