EFFECTS OF THE NEW IMIDAZOPYRIDINE CL-86-02-01 ON ISOLATED PAPILLARY-MUSCLE OF GUINEA-PIG HEARTS

Inotropic activity and the effect of CL 86-02-01 ethylsulfinyl-2-thien yl)-1H-imidazo[4,5-c]pyridine hydrochloride, CAS 109 792-24-7) on memb rane resting and action potentials were studied in isolated guinea-pig papillary muscles. Membrane resting potential and action potential pa rameters were not significantly changed, while CL 86-02-01 exerted a c oncentration-dependent inotropic effect by increasing the maximum rate of force development and maximum rate of force relaxation. Time to pe ak force, relaxation time and total contraction time were reduced. The se effects are similar to those of beta-adrenergic drugs and phosphodi esterase inhibitors, but markedly differ from those described for othe r positive inotropic agents like cardiac glycosides, calcium agonists, alpha-adrenergic drugs or increased extracellular calcium concentrati on.