Entrainment and phase shifting of circadian rhythms in mice by forced treadmill running

Physiol Behav. 1996 Aug;60(2):657-63. doi: 10.1016/s0031-9384(96)80045-x.

Abstract

Daily schedules of spontaneous, drug-, or novelty-induced running can entrain circadian rhythms in rodents. Forced running, by contrast, has been reported to have weak or no effects, although a thorough comparative study in a single species is lacking. To fill this gap, drinking or activity rhythms were monitored in C57 mice subjected to daily, 3-h bouts of forced treadmill running or to 3-h daily access to home cage running wheels. Entrainment to treadmill running was observed in 17/27 mice, and to restricted wheel access in 11/20 mice. Entrainment was affected by availability of a home cage wheel (e.g., 14/16 mice with no wheel entrained to treadmill running). Phase angle of entrainment was related to prior circadian period (tau), and tau following entrainment exhibited aftereffects. No mice entrained to a 3-h daily schedule of water access, suggesting that entrainment to scheduled running was not related to water or associated food intake. Phase shifts in response to single 3-h bouts of treadmill running or wheel access were small and not reliably induced. The entrainment paradigm is thus recommended for further study of behavioral effects on the mouse circadian system; forced running, in particular, offers several methodological advantages. The results do not support prior suggestions that forced and voluntary activity differ in value as nonphotic zeitgebers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Circadian Rhythm / physiology*
  • Drinking / physiology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Motor Activity / physiology
  • Physical Exertion / physiology*