Correlation Between the Results of Functional and Receptor Binding Studies in Cardiac Muscle
Studies comparing the negative inotropic effect of calcium antagonists and “related” receptor-affinities showed inconsistent results. We tested the possible relationship between the potency in inhibiting CaCl2-induced positive inotropy and receptor affinity. Therefore, we determined the relative potency of Nifedipine, Verapamil, Fendiline, Bepridil and Diltiazem both in isolated rabbit papillary muscle against CaCl2-induced positive inotropy (pA2) and their relative affinity (-log KD) in receptor binding experiments in rat cardiac homogenates.
KeywordsCardiac Muscle Relative Potency Negative Inotropic Effect Receptor Binding Affinity Receptor Binding Study