Investigation of K_(ATP) channel on ischemic preconditioning

[Objective] To investigate the effect of KATP channel on ischemic preconditioning. [Methods] The snare for occlusion and reperfusion had been put into the anterior descending coronary artery in 60 rats which were divided into 5 groups: ischemic/reperfusion (IR) group, ischemic preconditioning (IP) group, nicorandil (NIC) group, glibenclamide (GLI) group, 5-HD group. The activity of creatine kinase (CK) and lactate dehydrogenase (LDH) in plasma and the infarct size were measured. The episode of arrhythmias was monitored. The ultrastructural changes of the myocardium were observed under electron microscope. [Results] Compared with IR group, IP groups decreased significantly the incidence of ventricular fibrillation and arrhythmia scores (P0.05), however, the arrhythmia of 5-HD group was aggravated. Compared with IR group, NIC group could mimic part of cardioprotective effect of IP group. The cardioprotective effect was completely disappeared in 5-HD group. [Conclusions] It is suspected that KATP channel is the effector of ischemic preconditioning. The effect of anti-ischemic cardioprotection is blocked by mitokATP-selective antagonist-glibenclamide. It is suspected that mitochondrial KATP channel plays a primary role in ischemic period of ischemic preconditioning.