AJP - Regulatory, Integrative and Comparative Physiology, Vol 261, Issue 4 819-R827, Copyright © 1991 by American Physiological Society
Restricted feeding entrains circadian wheel-running activity rhythms of the kowari
G. A. Kennedy, G. J. Coleman and S. M. Armstrong
Department of Psychology, La Trobe University, Bundoora, Victoria, Australia.
The effect of daily restricted feeding (RF) on the circadian wheel-running
rhythms of the kowari, Dasyuroides byrnei, was examined in two experiments.
Kowaris were presented with a preferred food (determined in a pilot study)
during a daily 2-h meal in the light period of a 14:10 light-dark (LD)
cycle (expts 1 and 2), during constant dark (DD) immediately after
termination of the LD cycle (expt 1), and during DD when kowaris were free
running (expt 1). Results showed that 1) RF elicited anticipatory activity
similar in duration and phasing to that observed in the rat; 2) cycles of
meal-associated activity free ran for up to 6 days after the termination of
RF; 3) activity persists at a phase near that of the former mealtime during
periods of food deprivation; and 4) activity indicative of beating between
two pacemakers occurred when feeding was restricted to the L period of LD
cycles. Together these observations suggest that the activity rhythms of
the kowari may be controlled by separate, but possibly coupled,
light-entrainable and food-entrainable pacemakers, as are those of the rat.
