title: Corticotropin-releasing factor antagonist attenuates defensive-withdrawal behavior elicited by odors of stressed conspecifics.
abstract: This study examined the hypothesis that defensive responsiveness induced by threatening stimuli of biological origin is mediated by the action of endogenous corticotropin-releasing factor (CRF). Rats were exposed for 15 min to a large open field containing a small chamber. Twenty-four hours later, rats received intracerebroventricular injections of either vehicle or 20 micrograms of alpha-helical CRF(9-41), a CRF receptor antagonist. After 20 min, rats were reexposed to the open field, which now contained odors of urine and feces from a stressed conspecific. In the reexposure test, vehicle- and antagonist-treated rats withdrew rapidly into the chamber. Antagonist-treated rats, however, emerged subsequently from the chamber to explore the open field as indicated by a significant increase in the number of passages made between the chamber and the open field. Results suggest that central injection of alpha-helical CRF(9-41) reduces the level of fear induced by odors associated with threat. In addition, CRF receptors are implicated in mediating the species-typical display of defensive-withdrawal behavior.
authors.affiliation: Department of Psychiatry, University of Wisconsin Medical School, Madison.
authors.forename: L K
authors.initials: LK
authors.lastname: Takahashi
authors.forename: N H
authors.initials: NH
authors.lastname: Kalin
authors.forename: E W
authors.initials: EW
authors.lastname: Baker
mesh_terms: D000818:Animals; D001143:Arousal / Q000187:drug effects*; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D004597:Electroshock; D005106:Exploratory Behavior / Q000187:drug effects*; D005239:Fear / Q000187:drug effects*; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D012903:Smell / Q000187:drug effects*; D012931:Social Environment
chemical_list: D010446:Peptide Fragments; D003346:Corticotropin-Releasing Hormone; C045089:corticotropin releasing hormone (9-41)