氧化苯胂对大鼠心室肌细胞L型Ca2+电流的影响

目的 :探讨氧化苯胂 （PAO） ,一种膜可通透的酪氨酸磷酸酶抑制剂 ,对大鼠心室肌细胞 L型 Ca2 +电流 （ICa,L）的影响。方法 :采用全细胞膜片钳技术记录大鼠心室肌细胞 ICa,L。结果 :1PAO对基础 ICa,L及β-肾上腺素受体激动剂异丙肾上腺素 （Iso）激发的 ICa,L有抑制作用 ;2 PAO对腺苷酸环化酶激动剂 forskolin激发的 ICa,L亦有抑制作用 ;3电极内液加入 1.5 mm ol/ L矾酸钠不能消除 PAO的作用 ;4PAO对 ICa,L的抑制作用可被二硫代苏糖醇反转。结论 :PAO抑制 ICa,L的作用与 c AMP- PKA-磷酸化途径和酪氨酸磷酸酶无关 ,可能与其使 L 型 Ca2 +通道蛋白上巯基氧化有关。

Effect of phenylarsine oxide on L-type calcium channel currents in isolated ventricular myocytes

AIM: To investigate the effect of phenylarsine oxide (PAO), one of membrane permeatable tyrosine phosphatase inhibitors, on the L-type calcium channel currents (I Ca,L ) in isolated ventricular myocytes. METHODS: I Ca,L was recorded by using the whole cell voltage clamp technique. RESULTS: PAO suppressed basal or isoproterenol (Iso)-activated I Ca,L . Inhibition of forskolin-activated I Ca,L by PAO was also observed. PAO was effective even in the presence of intrapipette sodium orthovanadate, a tyrosine phosphatase inhibitor. Dithiothreitol, a reducing agent, reversed the effect of the inhibition of PAO on the currents. CONCLUSION: PAO inhibits I Ca,L is probably an oxidative effect directly on the -SH of the Ca 2+ channels.