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目的:研究Kvβ1.3亚基和Kv1.5共表达时,对表达在非洲爪蟾卵母细胞的Kv1.5通道DPO-1的阻断作用的影响。方法:在非洲爪蟾卵母细胞上异源表达克隆Kv1.5及Kvβ1.3通道基因,用双电极电压钳技术记录全细胞电流,检测药物对Kv1.5通道及Kv1.5+Kvβ1.3共表达通道电流的影响。结果:DPO-1以电压、频率及浓度依赖方式抑制Kv1.5+Kvβ1.3共表达通道的电流。Kvβ1.3亚基存在时,DPO-1的阻断效应明显减弱,DPO-1阻断的IC50由(0.77士0.12)μmol/L显著增加至(47.21士5.18)μmol/L,增加了约60倍(P<0.01)。结论:Kvβ1.3亚基显著抑制DPO-1对表达在卵母细胞上的Kv1.5通道的阻断作用,但不改变其电压、频率及浓度依赖性,可能机制是Kvβ1.3亚基与DPO-1相互竞争Kv1.5孔区内部的某些结合位点。
AIM: To investigate the effect of Kvβ1.3 subunit and Kv1.5 co-expression on the blockade of Kv1.5 channel DPO-1 expression in Xenopus laevis oocytes. Methods: The cloned Kv1.5 and Kvβ1.3 channel genes were heterologously expressed on Xenopus laevis oocytes. Whole-cell currents were recorded by two-electrode voltage-clamp technique. The effects of drugs on Kv1.5 channel and Kv1.5 + Kvβ1.3 Co-expression channel current effects. Results: DPO-1 inhibited the current of Kv1.5 + Kvβ1.3 co-expression channel in a voltage, frequency and concentration-dependent manner. The blocking effect of DPO-1 was significantly reduced in the presence of Kvβ1 subunit, and the IC50 of DPO-1 blocked significantly increased from (0.77 ± 0.12) μmol / L to (47.21 ± 5.18) μmol / L with an increase of about 60 Times (P <0.01). Conclusion: Kvβ1.3 subunit significantly inhibits the blocking effect of DPO-1 on Kv1.5 channel expressed in oocytes, but does not change the voltage, frequency and concentration-dependent manner. The possible mechanism is that Kvβ1.3 subunit and DPO-1 competes with each other for certain binding sites inside the Kv1.5 pore region.