Effects of corticotropin-releasing factor on circadian locomotor rhythm in the golden hamster.
Stress produces a reduction in the amplitude of some circadian rhythms. The neurochemical mechanisms underlying stress-induced changes in circadian rhythms are not known. To investigate a possible role of corticotropin-releasing factor (CRF) in this phenomenon, three related experiments were carried out: activity rhythms of male golden hamsters (10/14 hours light/dark entrained, lights on at 0800 h) were measured 1) following the intracerebroventricular administration of CRF (0.5, 1.0, 2.0, or 4.0 microg) at two different times of day, 2) following social stress (30-min resident-intruder confrontation), 3) and following the administration of the CRF-antagonist alpha-helical CRF9-41 (2.0 microg) prior to a 15-min resident-intruder confrontation. CRF produced a significant, dose-related decrease in circadian rhythm amplitude following administration in the morning hours, but not in the afternoon. CRF also induced transient increases in activity post injection concomitant with an activation of the hypothalamic-pituitary-adrenocortical (HPA) system. Stress similarly reduced the amplitude of activity patterns and stimulated the HPA system. The stress-induced depression of circadian rhythm amplitude was significantly attenuated following alpha-helical CRF9-41. These data suggest a role for CRF in the stress-related modulation of circadian locomotor rhythm amplitude.
Seifritz
E
E
Veterans Affairs Medical Center and Department of Psychiatry, University of California at San Diego, 92161, USA.
Klemfuss
H
H
Montes
J M
JM
Britton
K T
KT
Ehlers
C L
CL
D000374:Aggression / Q000187:drug effects; D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects*; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology*; D006224:Cricetinae; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D008647:Mesocricetus; D009043:Motor Activity / Q000187:drug effects*; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000502:physiology
C050191:alpha-helical corticotropin releasing hormone (3-41), Tyr(3), Pro(4), Nle(18,21)-; D003346:Corticotropin-Releasing Hormone