Author(s): Gong JS, Yao YT, Fang NX, Huang J, Li LH
BACKGROUND: It has been proved that sevoflurane postconditioning (SpostC) could protect the heart against myocardial ischemia/reperfusion injury, however, there has been few research focused on the electrophysiological effects of SpostC. The objective of the study was to investigate the effects of SpostC on action potential duration (APD) and L-type calcium current (I(Ca, L)) in isolated cardiomyocytes. METHODS: Langendorff perfused SD rat hearts were randomly assigned to one of the time control (TC), ischemia/reperfusion (I/R, 25 minutes of ischemia followed by 30 minutes of reperfusion), and SpostC (postconditioned with 3% sevoflurane) groups. At the end of reperfusion, epicardial myocytes were dissociated enzymatically for patch clamp studies. RESULTS: Sevoflurane directly prolonged APD and decreased peak I(Ca, L) densities in epicardial myocytes of the TC group (P < 0.05). I/R injury shortened APD and decreased peak I(Ca, L) densities in epicardial myocytes of the I/R group (P < 0.05). SpostC prolonged APD and increased peak I(Ca, L) densities in epicardial myocytes exposed to I/R injury (P < 0.05). SpostC decreased intracellular reactive oxygen species (ROS) levels, reduced the incidence of ventricular tachycardia and ventricular fibrillation, and decreased reperfusion arrhythmia scores compared with the I/R group (all P < 0.05). CONCLUSIONS: SpostC attenuates APD shortening and I(Ca, L) suppression induced by I/R injury. The regulation of APD and I(Ca, L) by SpostC might be related with intracellular ROS modulation, which contributes to the alleviation of reperfusion ventricular arrhythmia.