ERK1/2通路在4-AP诱导大鼠肺动脉收缩中的作用

4-AP induced normoxic rat pulmonary vasoconstriction through ERK1/2 signaling pathways

目的探讨细胞外信号调节激酶-1/2(ERK1/2)通路在4-氨基吡啶(4-aminopyridione,4-AP)阻断正常大鼠肺动脉平滑肌细胞(PASMCs)膜上电压依赖性钾通道(KV)所引起的肺动脉收缩中的作用。方法取正常鼠肺动脉制作肺动脉环,分别加入4-AP(KV通道阻断剂),PD98059/U0126+4-AP,比较肺动脉收缩的变化。同时培养肺动脉平滑肌细胞进行Western blot分析4-AP对ERK1/2的影响。结果①在血管环试验中,4-AP引起的肺动脉收缩有浓度依赖性;加入20mmol.L-1PD98059或2μmol.L-1U0126可以抑制4-AP引起的肺动脉收缩。②4-AP可刺激PASMCs ERK1/2蛋白磷酸化;③U0126可抑制4-AP引起的ERK1/2蛋白磷酸化。结论ERK1/2通路参与4-AP阻断正常大鼠肺动脉平滑肌细胞膜上电压依赖性钾通道(KV)引起肺动脉收缩。

Aim The purpose of this study was to ascertain whether the extracellular signal regulated kinase-1/2 （ERK1/2） pathways were involved in normoxic pulmonary artery （PA） constriction induced by 4-aminopyridione （4-AP）. Methods Organ bath for pulmonary artery rings tension study was employed. Adult male Wistar rats PAs 1 - 1.5 mm in diameter were isolated and cut into rings with 3 mm long for tension studies. ERK1/2 up-stream kinase （MEK） inhibitors PD98059 and U0126, which blocked the activation of ERK1/2, were used. Effects of 4-AP on ERK1/2 protein expression of pulmonary aterial smooth muscle cells （PASMCs） were measured by Western blot. Results Results showed that 4-AP-caused constrictionswere significantly blunted by PD98059 （20 mmol·L^-1） and U0126 （2 μmol·L^-1） pretreatment in the rings from normoxic rat. Moreover, 4-AP-caused constrictions significantly depend on concentration response; Phosphorylation of ERK1/2 at Thr202/Tyr204 in rat PASMCs was enhanced evidently by 4-AP （3 mmol·L^-1） stimulation; U0126 was significantly inhibited phosphorylations of ERK1/2 protein induced by 4-AP. Conclusion ERK1/2 signaling pathways is involved in 4-AP induced normoxic rat constrictions. pulmonary arterial constrictions.