EFFECTS OF VOLATILE ANESTHETICS ON PH ACTIVITY AND ISCHEMIC-REPERFUSION INJURY IN MYOCARDIAL CELLS

研究了挥发性麻醉药对缺血再灌注损伤心肌细胞pH活性的影响。在这项研究中，我们检测了离体兔心室肌细胞的pH活性、Ca2+瞬态和收缩力。分别用荧光pH指示剂（BCFCE）、Na+指示剂（SBFI）和Ca2+指示剂（Fluo-3）测定细胞内H+浓度（pHi）、Na+浓度（[Na+]i）和Ca2+浓度（[Ca2+]i）。通过电场刺激时细胞缩短的变化来评估收缩性。实验在细胞外pH 7.4， HEPES缓冲液存在下进行。结果表明：1)与异氟烷相比，氟烷可显著降低心肌收缩力；2)氟烷和异氟烷可减弱再灌注期心肌pHi的下降幅度；3)氟烷和异氟烷可减弱缺血期心肌pHi的下降幅度。提示氟烷和异氟烷所致的再灌注后细胞内过量氢的减少可能有利于兔完整心肌再灌注后的心肌功能。

We studied the effects of volatile anesthetics on pH activity in myocardial cells during ischemic-reperfusion injury. In this study, we examined pH activity, Ca2+ transients, and contractility in isolated rabbit ventricular myocytes. Intracellular H+ concentration (pHi), Na+ concentration ([Na+]i) and Ca2+ concentration ([Ca2+]i) were measured with the fluorescent pH indicators (BCFCE), Na+ indicators (SBFI) and Ca2+ indicators (Fluo-3), respectively. Contractility was assessed from changes in cell shortening during field stimulation. Experiments were performed at extracellular pH 7.4 in the presence of HEPES buffer. Our findings demonstrate that 1) halothane significantly decreased contractility compared with isoflurane, 2) halothane and isoflurane attenuate the magnitude in decreases in pHi during reperfusion, 3) halothane and isoflurane attenuate the magnitude in decreases in pHi during ischemic period. It is suggested that a reduction of excessive intracellular hydrogen after reperfusion caused by halothane and isoflurane may be beneficial on myocardial function following reperfusion in the intact rabbit myocardium.