Role of sarcolemmal KATP channel in sevoflurane-induced maintenance of electrophysiological stabili-ty of ventricular myocardium in diabetic rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of sarcolemmal ATP-sensitive potassium ( sarcKATP ) channel in sevoflurane-induced maintenance of electrophysiological stability of ventricular myocardium in di-abetic rats. Methods Clean-grade healthy male Sprague-Dawley rats, aged 3 months, weighing 280-320 g, in which diabetes mellitus ( DM) was induced by intraperitoneal streptozotocin 60 mg/kg and confirmed by blood glucose ≥16. 7 mmol/L, were used in this study. Their hearts were excised after anesthesia and retrogradely perfused in a Langendorff apparatus at 4 weeks after establishing the DM model. Twenty-four Langendorff-perfused hearts were divided into 3 groups ( n=8 each) using a random number table method:DM group ( group D) , DM plus sevoflurane group ( group DS) and DM plus sevoflurane plus HMR-1098 group (group DSH). Another 8 Langendorff-perfused hearts of normal rats were selected as control group ( group C) . Hearts were perfused with 37℃ K-H solution via the aorta in each group, 15 min of equilibra-tion later hearts were continuously perfused for 30 min with K-H solution in C and D groups, with K-H solu-tion saturated with 2. 5％ sevoflurane in group DS, or with K-H solution saturated with 10 μmol/L HMR-1098 and 2. 5％ sevoflurane in group DSH. Monophasic action potential (MAP) duration at 50％ and 90％repolarization ( MAPD50 and MAPD90 ) in the endocardium and epicardium of the left ventricular anterior wall were recorded at 15 min of equilibration ( T0 ) and 15 and 30 min of reperfusion ( T1,2 ) , transmural dispersion of repolarization ( TDR) was calculated. S1S2 program-controlled stimulation was performed at the end of perfusion to record the effective refractory period (ERP), ventricular arrhythmia (VA) induced and the longest pacing cycle length ( PCL) of ventricular fibrillation threshold ( VFT) induced. ERP/MAPD90 ratio was calculated. Results Compared with group C, TDR was significantly increased at T0 , ERP/MADP90 ratio was decreased, the incidence of VA induced was increased, and the longest PCL of VFT induced was prolonged in group D ( P＜0. 05) . Compared with group D, TDR was significantly decreased at T2 in group DS (P＜0. 05), and ERP/MADP90 ratio was significantly increased, the incidence of VA in-duced was decreased, and the longest PCL of VFT induced was shortened in DS and DSH groups ( P＜0. 05). TDR was significantly smaller at T2 in group DSH than in group DS (P＜0. 05). Conclusion sarcKATP channel is involved in sevoflurane-induced maintenance of electrophysiological stability of ventricu-lar myocardium in diabetic rats.