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Effects of remifentanil on intracellular Ca(2+) and its transients induced by electrical stimulation and caffeine in rat ventricular myocytes.

BACKGROUND
Preconditioning with remifentanil confers cardioprotection. Since Ca(2+) overload is a precipitating factor of injury, we determined the effects of remefentanil on intracellular Ca(2+) ([Ca(2+)](i)) and its transients induced by electrical stimulation and caffeine, which reflects Ca(2+) handling by Ca(2+) 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 microg/L was administered. Ten minutes after administration, either 0.2 Hz electrical stimulation was applied or 10 mmol/L caffeine was added. The [Ca(2+)](i), and the amplitude, time resting and 50% decay (t(50)) of both transients induced by electrical stimulation (E [Ca(2+)](i)) and caffeine (C [Ca(2+)](i)) were determined.


RESULTS
Remifentanil (0.1 - 1000.0 microg/L) decreased the [Ca(2+)](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 [Ca(2+)](i) and suppressed the transients induced by electrical stimulation and caffeine in rat ventricular myocytes.