Cardiovascular Effects of Orally Administered HNS-32, an Originally Synthesized Azulene-1-carboxamidine Derivative, Assessed in the In Vivo Rat Model

HNS-32, an azulene-1-carboxamidine derivative, is an originally synthesized antiarrhythmic compound. Its cardiovascular effects after oral administration (1 – 10 mg/kg) were assessed using the pentobarbital-anesthetized in vivo rat model in comparison with those of verapamil (3 mg/kg, p.o.). Verapamil decreased the heart rate and mean blood pressure and prolonged the PR interval without changing the QRS width (n = 6). Similar results were observed for HNS-32 except that the QRS width was prolonged by the highest dose and the effects occurred slowly and lasted longer. These results suggest that HNS-32 is an orally active slowly-acting calcium plus sodium channel blocker.