Purpose To elucidate the effects of propofol on cardiac contraction by measuring
intracellular Ca 2+ concentration changed
in neonatal or adult rats
ventricular myocytes. Methods Ventricular myocytes of neonatal or adult rats were cultured or acutely isolated respectively,then were loaded with Fluo-3AM,a new Ca 2+ indicator.The effects of propofol (50,250 μmol/L) on changes of
intracellular Ca 2+ fluorescent intensity induced by KCl and caffeine were investigated. Results Propofol caused dose-dependent inhibit Ca 2+ transsarcolemmal influx induced by KCl,peak Ca 2+ fluorescent intensity decreased significantly.The inhibitory effect was more obvious in neonatal ventricular myocytes than in adult at equiopotency of propofol.But propofol didn't alter the amount of Ca 2+ release from intracellular stores in response to caffeine in two kind of myocytes. Conclusions These results indicate that the negative inotropic effects of propofol,at least in part,may be mediated by a decrease of Ca 2+ transsarcolemmal influx through calcium channel,but may not relate to sarcoplasmic reticulum Ca 2+ release.And the effects on neonate is greater than on adult,which should be considered seriously in clinic use.