AIM: To determine the effect of hydrogen peroxide(H_2O_2) on voltage-gated potassium channel currents(IKv) in pulmonary vascular smooth muscle cells(PASMCs).METHODS: Using whole cell patch-clamp technique,IKv was recorded in freshly isolated rat PASMCs with acute enzymatic digestion method.The effect of hydrogen peroxide on IKv in PASMCs was investigated in normoxia.RESULTS: IKv in PASMCs was increased significantly by H_2O_2 and the increase depended on the concentration in normoxia.Current-voltage relationship curve shifted to the left.CONCLUSION: Hydrogen peroxide is an important K~+ channel opener.

AIM:To determine the role of Kv1 2, Kv1 5, Kv2 1 in the hypoxia pulmonary vasoconstriction (HPV). METHODS: Male Wistar rats were divided into two groups: normoxic group and hypoxic group. The single smooth muscle cell was obtained from pulmonary artery of Wistar rats with acute enzymatic digestion method. The conventional whole-cell patch clamp technique was used to record the resting membrane potential (Em) and the potassium currents of voltage-gated potassium channel (IKv) in rat pulmonary arterial smooth muscle cells (PASMC). Intracellular application of Kv1 2/Kv1 5/Kv2 1 antibodies (1∶125) was conducted through the whole-cell patch clamp system. RESULTS: ① Em of PASMC was depolarized after 24 h hypoxia compared with that of control cells [from (-51 8?0 8) mV to (-47 2? 0 7) mV, P