硝普钠对犬瘟热模型犬支气管平滑肌细胞电压门控性钾通道的影响

应用细胞膜片钳技术,分别测定正常对照组、犬瘟热(CD)模型组、CD 硝普钠(SNP)组犬支气管平滑肌细胞(BSMC)电压门控性钾通道(Kv)动力学指标、静息膜电位(Em)、静息膜电容(Cm)和电流密度。结果显示,CD组BSMC膜Kv活性显著降低,与对照组差异极显著(P<0.01)。经0.01 mmol/L SNP作用后, Kv通道开放时间显著延长,通道关闭时间缩短,通道开放频率明显增加,电流密度增大,静息膜电位(绝对值)升高,静息膜电容降低。表明,NO 能拮抗CD 模型犬BSMC膜Kv通道活性的抑制,恢复降低的钾电流,使细胞膜复极化,降低CD模型犬BSMC的兴奋性,对支气管平滑肌有松弛作用。

Effects of sodium nitroprusside on voltage-gated K+ channels of bronchial smooth muscle cells from canine distemper model dogs

The voltage-gated K~ (Kv) channels dynamical indexes, resting membrane potential(E_m) and electric capacity(C_m), and current density of bronchial smooth muscle cells(BSMC) of control group, canine distemper(CD) model group, CD SNP(sodium nitroprusside) group were determined by the cell patch clamp technique. The results indicated that the activation of Kv channels from CD group was inhibited significantly(P<0.01). After addition of NO donor SNP, the open time prolonged significantly, the close time shorted significantly, the open frequency of Kv channels, the current density and the resting E_m increased significantly, and the resting C_m decreased significantly. The results showed that the inhibition of BSMC Kv of CD was antagonized by NO, NO increased significantly the activation of Kv channel of BSMC from CD dogs and relaxed bronchial smooth muscle cells.