pituitrin and cilnidipine

We assessed the anti-anginal effects of cilnidipine in comparison with those of nicardipine and nifedipine (1 and 10 µg/kg, n = 6 for each drug) or vehicle (n = 6) by using the vasopressin-induced angina model of rats. The administration of vasopressin (0.5 IU/kg, i.v.) to the rats depressed the S-wave level of the electrocardiogram reflecting the presence of subendocardial ischemia, whereas it significantly increased the mean blood pressure, resulting in the decrease of the heart rate and the prolongation of the PR interval possibly through a reflex-mediated increase in vagal tone. Cilnidipine suppressed the vasopressin-induced depression of the S-wave level in a dose-related manner, which was not observed by nicardipine or nifedipine. In addition, the low dose of cilnidipine hardly affected the vasopressin-induced pressor response, but it attenuated the negative dromotropic effect, suggesting N-type Ca

Topics: Angina Pectoris; Animals; Blood Pressure; Calcium Channel Blockers; Calcium Channels, L-Type; Calcium Channels, N-Type; Coronary Vasospasm; Coronary Vessels; Dihydropyridines; Disease Models, Animal; Dose-Response Relationship, Drug; Electrocardiography; Heart Rate; Male; Nicardipine; Nifedipine; Rats; Time Factors; Vasoconstriction; Vasodilator Agents; Vasopressins