苄基四氢巴马汀对豚鼠心室肌细胞钾电流及钙、钠电流的作用

目的：研究苄基四氢巴马汀（BTHP）对心肌细胞的作用特点，以探讨其抗心律失常机制。方法：用全细胞膜片钳技术考察BTHP对心室肌细胞钾电流及钙、钠电流的作用。结果：BTHP 30 μmol.L^-1明显阻滞延迟整流钾电流（I_K包括：I_Kr及I_Ks）。可使I_Kr及I_Kr，tail的幅值下降，且对I_Kr阻滞作用呈频率依赖性；对I_Ks及I_Ks，tail幅值也有明显的抑制作用。BTHP 200　μmol.L^-1可明显阻滞I_Ca，L，使其电流幅值降低，但对I_K1，I_Ca，T，I_Na电流均无影响。结论：BTHP可明显阻滞心室肌细胞I_Kr，I_Ks，I_Ca，L电流，且对I_Kr阻滞作用呈频率依赖性。

EFFECTS OF BENZYLENZYLTETRAHYDROPALMATINE(BTHP) ON POTASSIUM CURRENTS AND CALCIUM, SODIUM CURRENTS IN GUINEA PIG VENTRICULAR MYOCYTES

AIM: To investigate the mechanism of antiarrhythmic action of benzylenzyl-tetrahydropalmatine(BTHP). METHODS: The effects of BTHP on potassium currents, calcium and sodium currents were studied in guinea pig single ventricular myocytes by using whole cell patch clamp technique. RESULTS: BTHP was shown to effectively block the two components of delayed rectifier potassium(I_K), ie I_Kr and I_Ks. I_Kr and I_Kr,tail were reduced from (0.68±0.27)　pA/pF and (0.94±0.44)　pA/pF to (0.47±0.18)　pA/pF and (0.60±0.32)　pA/pF, respectively by BTHP (30　μmol.L^-1) in a frequency-dependent fashion. I_Ks and I_Ks,tail were obviously inhibited from (12.1±1.78) pA/pF and (4.22±0.56) pA/pF to (7.25±0.87) pA/pF and (2.58±0.91) pA/pF after exposure to 30 μmol.L^-1 BTHP. I_Ca，L was also decreased from (14.48±0.26)　pA/pF to (10.44±0.32)　pA/pF by BTHP（200　μmol.L^-1）,　but BTHP was shown not to affect IK1, I_Ca,T and I_Na. CONCLUSION: BTHP significantly blocked I_Kr，　I_Ks and I_Ca，L, while I_Kr was inhibited by BTHP in a frequency-dependent fashion.