Effects of remifentanil on intracellular Ca2+ and its transients induced by electrical stimulation and caffeine in rat ventricular myocytes

Background Preconditioning with remifentanil confers cardioprotection. Since Ca2+ overload is a precipitating factor of injury, we determined the effects of remefentanil on intracellular Ca2+ ([Ca2+](i)) and its transients induced by electrical stimulation and caffeine, which reflects Ca2+ handling by Ca2+ handling proteins, in rat ventricular myocytes. Methods Freshly isolated adult male Sprague-Dawley rat myocytes were loaded with Fura-2/AM and [Ca](i) was determined by spectrofluorometry. Remifentanil at 0.1-1000 mu g/L was administered. Ten minutes after administration, either 0.2 Hz electrical stimulation was applied or 10 mmol/L caffeine was added. The [Ca2+](i), and the amplitude, time resting and 50% decay (t(50)) of both transients induced by electrical stimulation (E[Ca2+](i)) and caffeine (C[Ca2+](i)) were determined. Results Remifentanil (0.1-1000.0 mu g/L) decreased the [Ca2+](i) in a dose-dependent manner. It also decreased the amplitude of both transients dose-dependently. Furthermore, it increased the time to peak and t(50) of both transients dose-dependently. Conclusion Remifentanil reduced the [Ca2+](i) and suppressed the transients induced by electrical stimulation and caffeine in rat ventricular myocytes. Chin Med J 2009;122(12):1439-1443