Stoynev A G, Ikonomov O C, Damova I A, Penev P D, Usunoff K G, Paloff A M
Department of Physiology, Medico-Biological Institute, Medical Academy, Sofia, Bulgaria.
Physiol Behav. 1990 Dec;48(6):795-9. doi: 10.1016/0031-9384(90)90229-w.
Short-term (1-h, 4-h and 12-h) and long-term (24-h) feeding responses to 24-h food deprivation (FD) or insulin treatment (IT) (8 mU/kg IP) were studied in male rats under a 12/12-h light/dark (L/D) cycle. The 24-h FD or the IT began either at onset (Dawn) or offset (Dusk) of the lights. In sham-operated rats (Shams) both protocols elicited greater short-term feeding responses at Dusk (p less than 0.05 or less). In suprachiasmatic nuclei (SCN)-lesioned rats the L/D variations in short-term responses were absent. In both SCN and Shams the 24-h feeding responses did not depend on stimuli time-schedule. We conclude that the regulation of short-term (circadian), but not long-term, feeding responses to metabolic stimuli is dependent on SCN integrity in the rat.
