[Effects of the destruction of the suprachiasmatic nuclei on the circadian rhythms of ACTH corticosterone and the general activity of female rats exposed to a aperiodic environment].
The effects of bilateral destruction of suprachiasmatic nuclei (SCN) on the temporal patterns of plasma concentrations in ACTH and corticosterone (sequential blood samples from an aortic cannula, at 4 h intervals over 48 h) and of general activity (stabilimeter recordings) were studied in female rats under constant illumination (LL : 10 lx). Under this arrhythmic environment, the SCN lesions induced a syndrome similar to that previously described in a photoperiodic environment (12 L-12 D). This SCN syndrome included : 1) blockade of the ACTH rhythm at baseline levels ; 2) maintained fluctuations of corticosterone, with either circadian or ultradian profiles ; 3) persistent rhythmicity of general activity, with a circadian periodicity in addition to ultradian periods. The persistence of a circadian rhythmicity in the SCN syndrome under arrhythmic environmental conditions, clearly argues in favour of the occurrence of endogenous components of the circadian pacemaker outside the SCN.
D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000818:Animals; D002940:Circadian Rhythm; D003345:Corticosterone / Q000097:blood*; D005260:Female; D007031:Hypothalamus / Q000502:physiology*; D008027:Light; D009043:Motor Activity / Q000502:physiology*; D010507:Periodicity; D051381:Rats; D011919:Rats, Inbred Strains; D013495:Supraoptic Nucleus / Q000502:physiology*; D013997:Time Factors
D000324:Adrenocorticotropic Hormone; D003345:Corticosterone
Effeets de la destruction des noyaux suprachiasmatiques sur les rythmes circadiens de l'ACTH, de la corticostérone et de l'activité générale chez des rattes soumises à un environnement apériodique.