COMPARISON OF THE EFFECTS OF KRN2391 AND OTHER CORONARY DILATORS ON PORCINE ISOLATED CORONARY-ARTERIES OF DIFFERENT SIZES

The present study was performed to determine whether KRN2391 yano-N'-( 2-nitroxyethyl)-3-pyridinecarboximidamide monomethanesulphonate), a no vel vasodilator, shows different effects on porcine isolated coronary arteries of different sizes. The vasodilating effects of KRN2391 on po rcine large (2.5-3.0 mm outer diam.) and small (0.8-1-0 mm) coronary a rteries were also compared with those of cromakalim, nicorandil, nifed ipine, nitroglycerin and adenosine. The relaxant effects of these drug s were examined in coronary arteries contracted by 25 mM KCl. Nitrogly cerin caused greater relaxation in large vessels than in small vessels . In contrast, adenosine, nifedipine and cromakalim caused greater rel axation in small vessels. However, there was no difference between lar ge and small vessels in the relaxing effects of KRN2391 and nicorandil . These unique features of KRN2391 and nicorandil appear to be benefic ial in ischaemic heart disease.