氨氯地平对大鼠心室肌细胞动作电位及细胞内钙离子浓度的影响

Effects of Amlodipine on Action Potential and Cytosolic Ca^(2+) of Rat Ventricular Cardiomycytes

目的探讨不同旋体氨氯地平(Aml)对Spraque-Dawley大鼠心室肌细胞动作电位(AP)及细胞内钙离子浓度的影响。方法采用酶消化法获得大鼠耐钙心室肌细胞,以全细胞膜片钳技术分别记录加入0.1、0.5、1、5和10μmol/L左旋、右旋和混旋Aml后大鼠心室肌细胞AP的变化。并用荧光探针Fura-2/AM测定细胞内钙离子浓度,比较1、5、10、50和100μmol/L左旋、右旋和混旋Aml对细胞内钙离子浓度的影响。结果①加入0.1、0.5、1、5和10μmol/L左旋、右旋和混旋Aml后,AP最大上升速率、AP幅度和超射无明显变化(P>0.05)。②加入0.1、0.5、1、5和10μmol/L左旋后,50%的AP时程(APD50)分别为(36.2±8.2)、(33.9±7.7)、(30.2±6.8)、(22.6±5.1)和(15.1±3.4)ms(P<0.05);加入混旋Aml后,APD50分别为(39.2±9.2)、(36.7±7.9)、(33.8±7.2)、(25.4±5.9)和(21.7±5.2)ms(P<0.05);加入右旋Aml后,APD50分别为(45.1±11.3)、(46.2±10.8)、(44.9±7.3)、(44.8±8.2)和(45.7±9.4)ms(P>0.05)。③左旋Aml和混旋Aml可降低细胞内钙离子浓度,不同浓度右旋Aml对细胞内钙离子浓度无影响。结论左旋Aml和混旋Aml对L-型钙通道有阻滞作用,从而缩短APD,而右旋Aml对L-型钙离子通道无阻滞作用,因而对APD无影响。

Objective To investigate effects of amlodipine（Aml） on action potential（AP） and cytosolic Ca^2＋ of Spraque-Dawley rat by different isomers. Methods Calcium-tolerant ventricular myocytes were iso- lated by enzyme digestion. AP changes in S-Aml, R-Aml and R, S-Aml with concentrations of 0.1, 0.5, 1, 5 and 10μmol/L were recorded respectively by whole cell configuration patch clamp, and concentrations of cytosolic Ca^2＋ were measured by fluorescent probe Fura-2/AM. Effects on cytosolic Ca^2＋ with S-Aml, R-Aml and R, S-Aml in 1, 5, 10, 50 and 100μmol/L were compared. Results （1）AP maximal velocity, AP amplitude and overshoot had no significant changes in S-Aml, R-Aml and R, S-Aml with concentrations of O. 1, 0. 5, 1, 5 and 10μmol/L（ P 〉 0.05） ; （2）50% of action potential duration（ APD50） was （ 36.2 ± 8.2）, （ 33.9 ± 7.7）, （30.2 ±6.8）, （22.6 ± 5.1） and （ 15.1 ± 3.4） ms, respectively（ P 〈 0.05） with the increase of S-Aml concentrations from 0.1 mol/L to 10 mol/L; APD50were （39.2 ±9.2）, （36.7 ±7.9）, （33.8±7.2）, （25.4 ± 5.9） and （21.7±5.2） ms, respectively（P 〈 0. 05） with the increase of P, S-Aml concentrations from 0.1μmol/L to 10μmol/L; APD50was （45.1 ± 11.3）, （46.2 ± 10.8）, （44.9 ± 7.3）, （44. 8 ± 8.2） and （45.7 ± 9.4 ） ms, respectively （ P 〉0.0 5 ） with the increase of P - Aml concentrations from 0.1μmol / L to 1 0μ mol/L.（3）S-Aml and R, S-Aml reduced concentrations of cytosolic Ca^2＋ . However, R-Aml in different concentrations had no effects on cytosolic Ca^2＋. Conclusion S-Aml and R, S-Aml can block L-type calcium channel and shorten APDs. R-Aml can not block L-type calcium channel and therefore has no effects on APD.