ICV-CRH alters stress-induced freezing behavior without affecting pain sensitivity.
Freezing is an adaptive response often induced by stressful, fear-eliciting stimuli. Three experiments with rats investigated the effects of intracerebroventricular (ICV) administration of corticotropin-releasing hormone (CRH) on freezing behavior and pain sensitivity. Experiments 1 and 3 demonstrated that ICV-CRH (300 ng) enhanced shock-elicited freezing. In Experiment 1, ICV-CRH also enhanced recovery from shock-elicited freezing, suggesting that the peptide has a biphasic effect. Experiments 2 and 3 established that CRH-induced freezing was not caused by heightened pain sensitivity. Interestingly, in Experiment 2, hot-plate exposure produced increased freezing that was attenuated by ICV-CRH. Thus, the direction of the ICV-CRH effect on freezing was found to depend on the nature of the stressor. These results suggest that endogenous CRH systems modulate stress-induced freezing.
Sherman
J E
JE
Psychiatry Service, William S. Middleton Memorial Veterans Hospital, Madison, WI 53705.
Kalin
N H
NH
D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D004597:Electroshock; D005239:Fear; D006120:Grooming / Q000187:drug effects; D007276:Injections, Intraventricular; D009043:Motor Activity / Q000187:drug effects; D010146:Pain / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013239:Stereotyped Behavior / Q000187:drug effects*; D013315:Stress, Psychological / Q000503:physiopathology*
D003346:Corticotropin-Releasing Hormone