Selective Blockade of α<inf>2</inf>-Adrenoceptor Subtypes Modulates Contractility of Rat Myocardium

Abstract

© 2016 Springer Science+Business Media New YorkThe study examined the dose-dependent effects of selective antagonists of α2A/D-, α2B-, and α2C- adrenoceptors applied in concentrations of 10—9-10—5 M on atrial and ventricular contractility of rat myocardium in vitro. Selective blockade of each α2-adrenoceptor subtype affected the contractile force of the atrial and ventricular strips. Various concentrations of α2A/D- and α2C-adrenoceptor antagonists produced positive inotropic effect on ventricular strips and negative effect on atrial strips. α2B-Adrenoceptor blocker in the majority of the tested concentrations produced a positive inotropic effect in both atria and ventricles.