Binding of 125i-cyanopindolol to beta-1-adreno-ceptors in a high and low affinity state

Abstract

Investigation of binding properties of (+ (- and (±125Iodocyanopindolol (ICYP) to ß1-adrenoceptors of guinea pig left ventricle membranes revealed that these radioligands bind to receptors in a high and low affinity state which is not influenced by guanylnucleotides. The contribution of the (+enantiomer to the binding of the racemic ligand at low receptor concentrations can be neglected since the dissociation time courses of (± and (-ICYP are identical. The existence of two affinity states of ßadrenoceptors interacting with the antagonist ICYP was evident from 1: biphasic dissociation kinetics and 2: from curvilinear Scatchard plots. © 1983 Informa UK Ltd All rights reserved: reproduction in..