[Effects of aprindine on the electromechanical coupling of the myocardium and smooth muscle].

The effect of aprindine on myocardial and smooth muscle preparations activity were studied. Aprindine exerts a marked inhibition of the rate and contractility of guinea pig isolated atria and counteracts the inotropic effect induced by calcium. On the isolated guinea-pig left atrium electrically driven, apridine was found to exert negative inotropic effect both at low and high rates of stimulation, without depressing the "post-stimulation" potentiation. In spontaneously active guinea-pig taenia coli aprindine induces stimulation and regularization of the mechanical and electrical activity; on the other hand, aprindine is able to inhibit the contraction induced by acetylcholine, and this inhibition is counteracted by increasing concentration of calcium. Aprindine exerts no influence on the electrical membrane resistence of the guinea-pig taenia coli.