Effect of Gαq／11 protein and ATP-sensitive potassium channels on prostaglandin E1 preconditioning in rat hearts

Effect of G(alphaq/11) protein and ATP-sensitive potassium channels on prostaglandin E(1) preconditioning in rat hearts

To investigate the effect of G~11 signaling pathway and ATP-sensitive potassium channels (KAxP channels) on prostaglandin E1 (PGE0 induced early and delay-preconditioning protection in rat hearts. METHODS: Two series of experiments were performed in Wistar rat hearts. In the first series of experiment, all rats were pretreated with PGE 40 min or 23 h 20 min before the experiment. Ischemia-reperfusion injury was induced by 30 min coronaryartery occlusion followed by 90 min reperfusion. Hemodynamics, infarct size, and scores of ventricular arrhythmias were measured. The expression of G~q/H protein in the heart was measured by Western blot analysis in the second series. RESULTS: Preconditioning with PGE~ (25 lag/kg ) markedly reduced infarct size, left ventricular enddiastolic pressure, and scores of ventricular arrhythmia. The effect of PGE1 was significantly attenuated by glibenclamide (1 mg/kg, ip), a nonselective KA~ channel inhibitor. PGE~ caused a significant increase in the expression of G~/~ protein. CONCLUSION: Activations of G~/H signal pathway and Kgrp channel played significantroles in the cardioprotection of PGE~ preconditioning in rat heart and might be an important mechanism of signal transduction pathway during the PGEj preconditioning.