Aging lengthens circadian period for wheel-running activity in C57BL mice.
Previous reports of age effects on circadian period in rodents show a slight shortening of period with age, with the exception of house mice (Mus domesticus) where a number of studies report mixed results. The present study consists of three comparisons of circadian period for wheel-running activity in young vs. older C57BL inbred mice following entrainment to 16:8 LD, 12:12 LD and 8:16 LD photoperiods. The free-running circadian period (tau(DD)) for wheel-running activity was significantly longer in older mice following entrainment to all three photoperiods. These results support a model of heterogeneous effects of aging on circadian period among different rodent species, and suggest that the lengthening of circadian period with age in house mice is not a function of age-dependent differences in after-effects imposed by prior entrainment.
Possidente
B
B
Department of Biology, Skidmore College Saratoga Springs, NY 12866, USA.
McEldowney
S
S
Pabon
A
A
D000375:Aging / Q000502:physiology*; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity; D017440:Photoperiod; D012420:Running