EFFECT OF NICORANDIL ON CARDIAC DYSFUNCTION DURING REPERFUSION IN NORMOTENSIVE AND SPONTANEOUSLY HYPERTENSIVE RATS

The cardioprotective effect of nicorandil, an opener of ATP-sensitive potassium channels, was studied in the isolated perfused hearts of the spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (W KY) rat, The hearts were subjected to 30 min of global ischemia follow ed by 30 min of reperfusion. Controls received no drug, In the nicoran dil group, the hearts were treated with 0.03 to 0.3 mmol/L nicorandil for 15 min before ischemia. Left ventricular developed pressure (LVDP) and end diastolic pressure (LVEDP) at 30 min of reperfusion were sign ificantly lower and larger, respectively; in SHR than in WKY rats. Nic orandil improved LVDP and decreased LVEDP at 30 min of reperfusion in both SHR and WKY rats dose-dependently. The hypertensive heart in the early stage is already susceptible to reperfusion-cardiac dysfunction. Nicorandil has a beneficial effect on the post-ischemic dysfunction i n both SHR and WKY rats.