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两例终末期心脏来源于心脏移植的受体病人 ,用酶解分离法获得心外膜下 (Epi)细胞 ,在全细胞钳制条件下观察人右心室Epi细胞瞬间外向钾电流 (Ito1 )的电生理特性。结果发现 :①Epi细胞具有强大的Ito1 ,在 0 .2Hz、+70mV和 37℃条件下 ,Epi细胞的峰值Ito1 离子流强度和密度分别达 1 940± 440pA、1 2 .9± 2 .6pA/pF ;②温度对Ito1 强度的影响明显 ,在 +70mV、0 .2Hz、2 2℃和 37℃条件下 ,Epi细胞峰值Ito1 强度和密度分别为 1 1 90± 31 0pA和 7.7±1 .8pA/pF、1 960± 465pA和 1 3 .1± 2 .8pA/pF ,差异有显著性 (P均 <0 .0 1 ) ;③Epi细胞Ito1 离子流强度表现出明显的频率依赖性 ,在 37℃和 +70mV、刺激频率分别为 0 .2 ,0 .5 ,1和 2Hz时 ,Epi细胞Ito1 离子流强度分别为 1 91 0±42 0 ,1 660± 360 ,1 4 1 0± 2 50 ,830± 1 4 0pA ,差异均有显著性 (P均 <0 .0 1 )。结论 :人右心室Epi细胞存在强大的Ito1 ,此为人右心室Epi细胞复极 1期一个突出的电生理特点 ,可能是Brugada综合征等疾病所致恶性心律失常的重要离子基础之一。
Two cases of end-stage heart were derived from recipients of heart transplantation. Epi cells were obtained by enzymatic dissociation. The transient outward potassium current (Ito1) of human right ventricular Epi cells was observed under the condition of whole-cell clamp Physiological characteristics. The results showed that: (1) Epi cells had strong Ito1, and the Ito1 ion current intensity and density of Epi cells reached 1 940 ± 440 pA and 1 2 .9 ± 2 .6 pA / pF at 0 .2 Hz, + 70 mV and 37 ℃ respectively ; ② The effect of temperature on the intensity of Ito1 was obvious. The intensity and density of peak Ito1 of Epi cells at + 70mV, 0.2Hz, 22 ℃ and 37 ℃ were 1 1 90 ± 31 0pA and 7.7 ± 1 .8pA / pF , 1 960 ± 465pA and 1 3 .1 ± 2 .8pA / pF, respectively (all P <0.01). (3) The intensity of Ito1 ion current in Epi cells showed obvious frequency dependence. The intensity of Ito1 ion current in Epi cells were respectively 1 91 0 ± 42 0, 1 660 ± 360, 1 41 0 ± 2 50, 830 ± 1 at 70mV stimulation frequency of 0.2, 0.5, 1 and 2Hz respectively 4 0pA, the difference was significant (P <0.01). Conclusion: There is a strong Ito1 in human right ventricular Epi cells. This is a prominent electrophysiological feature of repolarization phase 1 in human right ventricular Epi cells, which may be one of the important ionic bases of malignant arrhythmia caused by diseases such as Brugada syndrome.