Abstract
1 β-Adrenoceptors of pig coronary arteries were investigated by the use of a new ligand, 125iodocyanopindolol (ICYP) in binding studies. 2 Inhibition of ICYP binding by betaxolol (a selective β1-antagonist), zinterol (a selective β2-agonist) and ICI 118551 (a selective β2-blocking drug) resulted in non-linear Scatchard plots, suggesting that both β-adrenoceptor subtypes are present in pig coronary arteries. 3 Computer analysis of the data gave a β12-adrenoceptor ratio of approximately 65:35.