Identification of beta-adrenergic receptor subtypes mediating relaxation in isolated equine ileum
Re, G.; Belloli, C.; Badino, P.; Arioli, F.; Novelli, A.; Girardi, C.; Beretta, C.
American Journal of Veterinary Research 58(6): 621-625
1997
ISSN/ISBN: 0002-9645 PMID: 9185969 Document Number: 480162
Objective-To identify beta-adrenergic receptor subtypes in ileum smooth muscle of the horse. Sample Population-Isolated strips of equine longitudinal ileum smooth muscle and membrane preparations from smooth muscle of the intestinal wall. Procedure-Functional assays and radioligand binding assays. Results-Relaxation of ileum longitudinal smooth muscle proved to be mainly caused by stimulation of beta-atypical and beta-2-adrenergic receptors. Binding studies on cell membranes indicated that the total beta-adrenergic receptors population consists of 54% beta-atypical, 34% beta-2-, and 12% beta-1-subtypes. Conclusions-The data suggest that sympathetic relaxation of equine ileum smooth muscle depends mainly on beta-atypical receptor subtypes activation, with Clinical Relevance-The important role of beta-atypical adrenergic receptor subtypes in the relaxation of equine ileum suggests possible clinical use of selective beta-atypical receptor agonists to control intestinal disturbances.