Central beta 1-adrenergic receptors are involved in CRF-induced defensive withdrawal.
Previous studies indicated that peripheral administration of propranolol, a nonselective beta-adrenergic antagonist, attenuated ICV CRF-induced suppression of a conditioned emotional response and defensive withdrawal behavior in rats, suggesting the involvement of a beta-adrenergic receptor in the CRF-induced behavioral changes. The present study was carried out to determine whether central or peripheral beta-adrenergic receptors are involved in CRF-induced defensive withdrawal behavior, and which subtype of beta-adrenergic receptor is involved. l-Propranolol (2.5 mg/kg IP) significantly reversed CRF-induced defensive withdrawal behavior. CGP-12177 (1 mg/kg IP), a beta-adrenergic antagonist with predominant effects on peripheral beta-adrenergic receptors, and ICI 118,551 (0.5 mg/kg IP), a selective beta 2-adrenergic antagonist, had no significant effects on CRF-induced defensive withdrawal. When administered ICV, two selective beta 1-adrenergic antagonists, CGP-20712A (10 micrograms) and atenolol (100 micrograms), significantly antagonized CRF-induced defensive withdrawal. Our results suggest that a central beta 1-adrenergic receptor is involved in CRF-induced defensive withdrawal in rats.
Yang
X M
XM
Department of Pharmacology and Therapeutics, Louisiana State University Medical Center, Shreveport 71130-3932.
Dunn
A J
AJ
D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects*; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D008297:Male; D011412:Propanolamines / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000502:physiology*
D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; C026777:ICI 118551; D001262:Atenolol; D003346:Corticotropin-Releasing Hormone; D011433:Propranolol; C033394:CGP 12177