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目的 观察压力增高导致的人肥厚心室组织离子通道的特性。方法 应用酶解分离技术从法乐四联症 (F4 )患儿的心脏右室得到单个细胞 ,应用膜片钳全细胞记录技术观察了细胞Ito1的特征。结果 将钙电流阻断后 ,去极化至 - 2 0mV～ +6 0mV时均可记录到Ito1,激活后电流衰减速度不随去极化程度的增强而改变 ,在 0、2 0、40、6 0mV时分别为 12 3ms± 6ms、131ms± 10ms、12 2ms± 6ms、12 2ms± 6ms,去极化至 6 0mV时的电流密度为 4.7pA/pF± 0 .8pA/pF ,半数最大激活电位为 4.1mV± 2 .8mV ,半数最大失活电位出现在 - 41mV± 4mV ,失活后再激活的恢复时间常数为 83ms± 4ms。这种电流可被 10mM4 AP基本抑制。结论 肥厚的人右室细胞存在Ito1,通道动力学特征与成人心房肌细胞类似。
Objective To observe the characteristics of ion channels in human hypertrophic ventricular tissue caused by the increase of pressure. Methods Single cell was obtained from the right ventricle of children with tetralogy of Fallot (F4) by enzymolysis and separation technique. The characteristics of Ito1 were observed by patch clamp whole cell recording. Results After calcium current was blocked, Ito1 could be recorded when depolarized to -20mV ~ +60mV. The decay rate of current did not change with the degree of depolarization after activation. At 0,2, 0, 40, The current densities at depolarization to 60 mV were 4.7 pA / pF ± 0 .8 pA / pF at half-maximal activation potentials of 12 ms ± 10 ms, 12 2 ms ± 6 ms, 12 2 ms ± 6 ms at 0 mV 4.1mV ± 2 .8mV, half of the maximum inactivation potential in - 41mV ± 4mV, reactivation after inactivation recovery time constant of 83ms ± 4ms. This current can be substantially inhibited by 10 mM 4 AP. Conclusions Ito1 is present in hypertrophied human right ventricular cells and has similar channel kinetic characteristics as adult atrial myocytes.