小鼠胚胎心肌细胞的I_f和I_(Ca-L)电流表达的发育依赖性变化

目的 :研究不同时期胚胎心肌细胞超极化激活的电流 (hyperpo larization activatedcurrent,If)和L 型钙电流 (L typecalciumcurrent,ICa L)表达的发育依赖性变化。方法 :运用全细胞膜片钳技术 ,记录不同发育阶段胚胎心肌细胞的If 和ICa L。结果 :If 通道在早期(EDS)、中期 (IDS)、晚期 (LDS)胚胎心室肌细胞上的功能性表达水平分别为 85 .70 %、71.60 %、44 .40 % ;其电流密度分别是 -7.2 4±1.2 8pApF- 1 、-6.48± 0 .99pApF- 1 、-3 .76± 1.0 4pApF- 1 (P均<0 .0 1)。If 通道在中、晚期胚胎心房肌细胞上的功能性表达水平分别为 77%、48.3 0 % (P <0 .0 1) ;其电流密度分别是 -8.86± 2 .3 4pApF- 1 与 -4 .62± 1.0 6pApF- 1 (P <0 .0 1)。早、中、晚期胚胎心肌细胞的ICa L的功能表达变化不明显 (P >0 .0 5 )。结论 :胚胎心肌细胞的If的功能表达呈发育依赖性下降 ,ICa L的功能表达没有发育依赖性改变

Developmental Changes of If and Ica-L on the Cardiomyocyte in Mice of Different Embryonic Stages

Objective: To study the developmental changes of hyperpolarization activated current (I f) and L type calcium current (I Ca L ) on the cardiomyocyte in mice of different embryonic stages.Method: I f and I Ca L were recorded by whole cell patch clamp recording technique.Results: The expression rate of I f channel of embryonic ventricular myocyte in EDS(early developmental stage), IDS(intermediate developmental stage) and LDS(late developmental stage) is 85.7%, 71.6% and 44.4%, respectively. Their current density is -7.24±1.28 pA pF -1 , -6.48±0.99 pA pF -1 and -3.76±1.04 pA pF -1 , respectively(all P <0.01). The expression rate of I f channel of embryonic atrial myocytes in IDS and LDS is 77% and 48.3%( P <0.01) respectively. Their current density of I f is -8.86±2.34 pA pF -1 and -4.62±1.06( P <0.01). However, there is no significantly difference in the current density of I Ca L of embryonic ventricular myocyte in EDS, IDS and LDS ( P >0.05).Conclusion: The expression of I f decreases development dependently, while there is no significantly difference of I Ca L during its development.