Effects of urocortin 2 and 3 on motor activity and food intake in rats.
Urocortin 2 (Ucn 2) and Ucn 3 are new members of the corticotropin-releasing factor (CRF) family and bind selectively to the CRF type 2 receptor (CRF2). The effects of these peptides on behavioral changes induced by CRF were examined in rats. In a familiar environment, intracerebroventricular injection of Ucn 2 attenuated the stimulatory effect of CRF on motor activity, although it alone produced no effect. Ucn 3 suppressed motor activity and attenuated the stimulatory effect of CRF. In an open field, CRF decreased locomotion and rearing but increased grooming behavior. Ucn 2 attenuated the inhibition of locomotor activity induced by CRF without affecting other activities, such as rearing or grooming behavior. Ucn 3 had no effect on the behavioral changes induced by CRF, although it alone decreased locomotion and rearing in a manner similar to CRF. Ucn 2 was thus found to have an antagonistic effect on bi-directional motor activation induced by CRF, while Ucn 3 had a suppressive effect on motor activity. Both Ucn 2 and Ucn 3 suppressed food intake in freely-fed rats, but not immediately after injection. These results suggest that the CRF2 receptor is involved in motor suppressive effects as well as anxiolytic and anorectic effects of Ucn 2 and Ucn 3.
Department of Physiology, Nippon Medical School, 1-1-5 Sendagi Bunkyo-ku, Tokyo 113-8602, Japan. h_ohata@nms.ac.jp
Hisayuki
H
Ohata
Tamotsu
T
Shibasaki
D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D002149:Energy Intake / Q000187:drug effects*; D005106:Exploratory Behavior / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D011187:Posture; D051381:Rats; D017208:Rats, Wistar; D054832:Urocortins
D054832:Urocortins; D003346:Corticotropin-Releasing Hormone