Studies of potassium channel in pulmonary artery smooth muscle cells of pulmonary hypertension rats

AIM：In this work,we investigated the difference of membrane capacitance,membrane current,current density and I-V curves between smooth muscle cells isolated from pulmonary hypertension rat (PHR) or normotensive rat (NTR) pulmonary arteries.METHODS：Thirty young male Sprague-Dawley rats,aged 8-9 weeks,were used.Body weight was (200±20)g at the start of experiments.These rats were placed into a normobaric chamber for 6 h·day-1,6 day·week-1 for 4 weeks.Hypoxic exposure was accomplished by ventilation with room air and N2 resulting in a constant O2 concentration of (10±0.5)%.Whole cell recordings were made from smooth muscle cells freshly isolated from pulmonary arteries derived from PHR or NTR.RESULTS：The membrane capacitance of pulmonary hypertension rats was larger than that in SD rats;but membrane current and current density were lower than those in SD rats (P<0.05).The I-V curves of pulmonary hypertension rat were downward shift compared with that in SD rat.Iptakalim hydrochloride 10 μmol·L-1 significantly increased potassium currents.CONCLUSIONS：Membrane capacitance,membrane current,membrane potential are decreased,I-V curves was shift downward,compared with NTR.Iptakalim hydrochloride significantly increased NTR and PHR potassium currents.