INVESTIGATIONS ON THE STEREOSELECTIVE ACTION OF ISOXSUPRINE ON ALFA AND BETA ADRENOCEPTORS IN EQUINE COMMON DIGITAL ARTERY
Articolo
Data di Pubblicazione:
1999
Citazione:
INVESTIGATIONS ON THE STEREOSELECTIVE ACTION OF ISOXSUPRINE ON ALFA AND BETA ADRENOCEPTORS IN EQUINE COMMON DIGITAL ARTERY / C.BELLOLI, P.BADINO, R.CARCANO, R. ODORE, F. ARIOLI, F. CALONI, G. RE G. - In: PHARMACOLOGICAL RESEARCH. - ISSN 1043-6618. - 40:2(1999), pp. 177-182.
Abstract:
The affinity and functional effects of isoxsuprine enantiomers were investigated to determine the enantiospecificity of the β-agonistic and α-blocking effects. Functional assays on isolated smooth muscle preparations from equine common digital artery were performed to determine the apparent affinity (pD2) and intrinsic activity (α(E)) of (-)erythro-isoxsuprine (αS, βR, γR) and (+)erythro-isoxsuprine (αR, βS, γS). The affinity of two enantiomers for the different adrenoceptor types was studied by radioligand binding assays on membrane preparations from the same tissue: using (-)[3H]CGP12177 and [3H]prazosin. On noradrenaline-precontracted artery preparations (-)isoxsuprine was markedly more potent than(+)isoxsuprine in dilating preparations, indicating that the laevorotatory enantiomer has a very high apparent affinity for α-adrenoceptors. Binding studies confirmed that (-)isoxsuprine has a higher affinity than (+)isoxsuprine for α-adrenoceptors, while the (+) isomer competes for β-adrenoceptors with an affinity similar to that of propranolol. As described for other β-phenylethylamines, the two isoxsuprine enantiomers studied have different efficacies for α- and β-adrenoceptors and the effects of the commercially available mixture of stereoisomers therefore depend on the density and functional importance of the adrenoceptor types present in the tissue studied.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
C.BELLOLI, P.BADINO, R.CARCANO, R. ODORE, F. ARIOLI, F. CALONI, G. RE G
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