AJP - Regulatory, Integrative and Comparative Physiology, Vol 235, Issue 3 175-R180, Copyright © 1978 by American Physiological Society
Circadian rhythm dissociation in an environment with conflicting temporal information
F. M. Sulzman, C. A. Fuller, L. G. Hiles and M. C. Moore-Ede
The relative contributions of light-dark (LD) cycles and feeding (EF)
cycles in providing temporal information to the circadian time-keeping
system were examined in chair-acclimatized squirrel monkeys (Saimiri
sciureus). The circadian rhythms of drinking, colonic temperature, urine
volume, and urinary potassium excretion were measured with the LD and EF
cycles providing either conflicting phases or periods. In conflicting phase
experiments, animals were exposed to 24-h LD cycles consisting of 12 h of
600 lx followed by 12 h of less than 1 ls and concurrent 24-h EF cycles in
which the animals ate for 3 h and then fasted for 21 h. One group had food
available at the beginning and a second group at the end of the light
period. In conflicting period experiments, monkeys were exposed to 23-h LD
cycles (LD 11.5:11.5) and 24-h EF cycles (EF 3:21). Analysis of the rhythms
showed that both phase and period information were conveyed to the drinking
and urinary rhythms by the EF cycle, and to the temperature rhythm by the
LD cycle.
