Scheduled exposures to a novel environment with a running-wheel differentially accelerate re-entrainment of mice peripheral clocks to new light-dark cycles.
Effects of scheduled exposures to novel environment with a running-wheel were examined on re-entrainment to 8 h shifted light-dark (LD) cycles of mouse circadian rhythms in locomotor activity and clock gene, Per1, expression in the suprachiasmatic nucleus (SCN) and peripheral tissues. Per1 expression was monitored by a bioluminescence reporter introduced into mice. The animals were exposed to the novel environment for 3 h from the shifted dark onset for four cycles and released into constant darkness. In the phase-advance shift, the circadian rhythm in locomotor activity fully re-entrained in the exposed group, whereas it was in transients in the control. On the other hand, the circadian rhythm of Per1 expression in the SCN almost completely re-entrained in both the control and exposed groups. In the skeletal muscle and lung, the circadian rhythm fully re-entrained in the exposed group, whereas the rhythms in the control did not. In the phase-delay shift, the circadian rhythms in locomotor activity and Per1 expression almost completely re-entrained in both groups. These findings indicate that the scheduled exposures to novel environment with a running-wheel differentially accelerate the re-entrainment of the mouse peripheral clocks to 8 h phase-advanced LD cycles.
Yamanaka
Yujiro
Y
Department of Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
Honma
Sato
S
Honma
Ken-ichi
K
D000818:Animals; D001683:Biological Clocks; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002940:Circadian Rhythm; D003624:Darkness; D008027:Light; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009043:Motor Activity; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D056950:Period Circadian Proteins; D013493:Suprachiasmatic Nucleus / Q000378:metabolism
D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C539023:Per1 protein, mouse; D056950:Period Circadian Proteins