Suprachiasmatic nuclei lesions eliminate light/dark variations in short-term feeding responses to deprivation or insulin treatment in rats.
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.
Stoynev
A G
AG
Department of Physiology, Medico-Biological Institute, Medical Academy, Sofia, Bulgaria.
Ikonomov
O C
OC
Damova
I A
IA
Penev
P D
PD
Usunoff
K G
KG
Paloff
A M
AM
D000818:Animals; D001931:Brain Mapping; D002940:Circadian Rhythm / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D006815:Hunger / Q000502:physiology*; D007328:Insulin / Q000502:physiology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013493:Suprachiasmatic Nucleus / Q000502:physiology*
D007328:Insulin