ISSN:
1440-1681
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
1.The mechanisms underlying the cardiovascular action of YC-93, a new dihydropyridine vasodilator with cyclic AMP phosphodiesterase inhibitory activity, was investigated by comparing its effects wth those of papaverine in various isolated, blood-perfused heart preparations of the dog.2. In all preparations YC-93 injected into the nutrient arteries produced a dose-dependent increase in blood flow, and in this respect YC-93 was about twenty times more potent than papaverine on a weight basis.3. In sinoatrial node preparations YC-93 injected into the sinus node artery decreased sinus rate in a dose-dependent manner, and in large doses produced atrial standstill.4. In atrioventricular (a.v.) node preparations YC-93 injected into the a.v. node artery increased a.v. conduction time in a dose-dependent manner, and in large doses produced a second or third degree block of a.v. conduction. However YC-93 injected into the anterior septal artery scarcely affected a.v. conduction.5. In spontaneously contracting papillary muscle preparations YC-93 injected into the anterior septal artery failed to affect ventricular automaticity in doses which markedly decreased developed tension of papillary muscles.6. In papillary muscle preparations driven at a fixed rate YC-93 injected into the anterior septal artery produced a dose-dependent decrease in developed tension of papillary muscles.7. Unlike YC-93, papaverine decreased a.v. conduction time in a.v. node preparations and increased developed tension of papillary muscle preparations.8. The cardiac effects of YC-93 elucidated in the present experiments are characteristic of calcium-antagonistic vasodilators. The action of YC-93 as an inhibitor of cyclic AMP phosphodiesterase does not appear to play a role in its cardiac action.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1440-1681.1980.tb00069.x
