Independence of feeding-associated circadian rhythm from light conditions and meal intervals in SCN lesioned rats.
Free-running period of the feeding-associated circadian rhythm was assessed in suprachiasmatic nucleus (SCN) lesioned rats under three different conditions using a feeding-fasting (FF) paradigm; restricted feeding (RF) with meal intervals of 24 h (T = 24 h) under 24 h light-dark cycle (LD), RF with T = 24 h under continuous dim light (dim LL), and RF with T = 25 h under dim LL. After the termination of RF, the rats were subjected to FF regimen five times repeatedly, in which food and water were available for 7 days, followed by total food deprivation for 3 days with free-access to water. Free-running period, which was measured with reference to the prefeeding activity peak during food deprivation, was very close to 24 h and was not different under three conditions. It is concluded that the feeding-associated circadian rhythm has a major period close to 24 h, which is not affected either by light conditions nor by meal intervals.
Yoshihara
T
T
Department of Physiology, Hokkaido University School of Medicine, Sapporo, Japan.
Honma
S
S
Mitome
M
M
Honma
K
K
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D004435:Eating / Q000502:physiology; D005215:Fasting / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D008027:Light; D008297:Male; D010507:Periodicity; D010805:Physical Conditioning, Animal / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012044:Regression Analysis; D013493:Suprachiasmatic Nucleus / Q000502:physiology* / Q000601:surgery*