The β‐adrenoceptor of pig coronary arteries: determination of β₁ and β₂ subtypes by radioligand binding

Abstract

beta-Adrenoceptors of pig coronary arteries were investigated by the use of a new ligand, 125iodocyanopindolol (ICYP) in binding studies. Inhibition of ICYP binding by betaxolol (a selective beta 1-antagonist), zinterol (a selective beta 2-agonist) and ICI 118551 (a selective beta 2-blocking drug) resulted in non-linear Scatchard plots, suggesting that both beta-adrenoceptor subtypes are present in pig coronary arteries. Computer analysis of the data gave a beta 1:beta 2-adrenoceptor ratio of approximately 65:35.