金雀异黄素对大鼠血管平滑肌细胞钾电流的影响

Genistein inhibits TEA-sensitive potassium currents of smooth muscle cells of mesenteric arteries in rats

目的观察金雀异黄素(GST)对大鼠肠系膜动脉平滑肌细胞(MASMC)钾电流(IK)的影响。方法采用急性酶分离法获得SD大鼠单个MASMC,应用全细胞膜片钳记录方法,研究GST对IK以及膜电位的影响。结果 (1)GST(100μmol/L)可以快速可逆的抑制IK(P<0.05),tyrphostin25(10μmol/L)也可抑制IK(P<0.05),其作用与GST类似,而Daidzein(100μmol/L)对IK没有显著影响(P>0.05)。(2)在电极内液不含ATP的条件下,GST(100μmol/L)和tyrphostin25(10μmol/L)对IK的抑制没有统计学意义(P>0.05)。(3)GST能浓度依赖性地去极化膜电位(P<0.05),而且此作用是可逆的。Daidzein(100μmol/L)、tyrophostin25(10μmol/L)则对膜电位没有明显影响(P>0.05)。结论 GST可以快速可逆的抑制IK,使膜电位去极化,其作用与酪氨酸磷酸化相关。

Objective To observe the effects of genistein on potassium currents of smooth muscle cells of mesenteric arteries(MASMC) in rats.Methods Single MASMC was obtained with acute enzyme dispersing method.The whole-cell patch-clamp technique was used to measure the membrane potential and potassium currents affected by genistein.Results(1) Genistein(100μmol/L)rapidly and reversibly inhibited potassium currents(P<0.05),which were insensitive to daidzein(100μmol/L)(P>0.05),whereas tyrphostin25(10μmol/L) had similar inhibitory effects as genistein(P<0.05).(2) The inhibition of potassium currents induced by genistein and tyrphostin25 was statistically insignificant(P>0.05) without ATP in the pipette.(3)Genistein(100μmol/L) reversibly and concentration-dependently depolarized the membrane potential of MASMC(P<0.05).Neither Daidzein(100μmol/L) nor tyrophostin25(10μmol/L) had any effects on membrane potential(P>0.05).Conclusions The present results suggest that genistein can rapidly and reversibly inhibit potassium currents and depolarize MASMC,which may be correlated with protein tyrosine phosphorylation.