丙泊酚对新生和成年大鼠心肌细胞钙离子移动的影响

The Effects of Propofol on Ca^(2+) Mobilization in Neonatal and Adult Rat's Ventricular Myocytes

目的 观察不同浓度丙泊酚对氯化钾和咖啡因诱发的新生和成年大鼠心肌细胞钙离子移动的影响 ,探讨其心肌抑制作用的可能机制。方法 用Fluo 3AM钙荧光指示剂染色培养的新生大鼠或急性分离的成年大鼠心肌细胞 ,在激光共聚焦显微镜下动态观察使用丙泊酚前及丙泊酚 (5 0 ,2 5 0 μmol/L)预处理后 ,氯化钾和咖啡因诱发的细胞内钙离子浓度的变化。结果 丙泊酚 5 0 μmol/L使氯化钾诱发的新生或成年大鼠心肌细胞内钙荧光强度的峰值下降 ,较对照组有明显差异 (P <0 .0 1 ) ,对新生大鼠心肌细胞的抑制作用较成年大鼠明显。丙泊酚 2 5 0 μmol/L使细胞内钙荧光强度峰值进一步降低。但两种浓度的丙泊酚对咖啡因诱发的两种心肌细胞钙荧光强度的升高均无明显影响 (P >0 .0 5 )。结论 丙泊酚浓度依赖地降低心肌细胞内钙离子浓度 ,与其抑制细胞外钙内流有关 ,它对新生大鼠心肌细胞的抑制作用更强。提示临床上使用丙泊酚作为麻醉剂 ,尤其对小儿麻醉时应有足够重视。

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.