Effects of nicorandil administration on survival rate and arrhythmias during reperfusion in anesthetized rabbits

The aim was to study the effects of nicorandil (an ATP-sensitive K+ channel opener) and tolbutamide (an ATP-sensitive K+ channel blocker) on reperfusi on-induced arrhythmias in pentobarbitone and ketamine anesthetized rabbits. Arrhythmias were induced by reperfusion for 20 min following a 15-min liga tion of the left main coronary artery with a silk ligature. Rabbits were pr etreated with nicorandil (0.47, 0.93 or 1.86 mg/kg Lv.) or tolbutamide (180 mg/kg Lp.) or vehicle (dimethylsulfoxide/saline) before the coronary arter y occlusion. In the control group (n = 10), only 60% of the animals survive d during reperfusion. Intravenous pretreatment with 0.47, 0.93 or 1.86 mg/k g of nicorandil increased the survival rate to 86% (n = 7), 75% (n = 8) and 86% (n = 7), respectively. Nicorandil pretreatment significantly decreased the incidence and duration of reperfusion-induced life-threatening arrhyth mias and increased the number of animals that survived without developing a ny arrhythmia. Tolbutamide pretreatment was associated with a decreased sur vival rate of 50% (n = 12) and an increase in the incidence and duration of reperfusion-induced arrhythmias. Pretreatment with nicorandil may result i n protection against reperfusion-induced arrhythmias and increased survival in anesthetized rabbits. Copyright (C) 2001 S. Karger AG, Basel.