AIMTo investigate the differences of membrane capacitance, membrane current, current density and I-V curves between smooth muscle cells isolated from RHR and NTR pulmonary arteries.

METHODSUnder antiseptic conditions, the left renal artery was exposed through a retroperitoneal flank incision and carefully dissected free of the left renal vein. A silver clip with an internal diameter of 0.2-0.3 mm was placed around the left renal artery, resulting in partial occlusion of renal perfusion. SBP was observed by tail blood pressure. Whole cell recordings were made from smooth muscle cells freshly isolated from pulmonary arteries derived from RHR or NTR.

RESULTSThe average membrane capacitance was (3.43 +/- 1.16) pF, decreased by 31.1%; membrane current was (0.54 +/- 0.26) nA, decreased by 68.2%; current density was (180 +/- 90) pA/pF, decreased by 48.6%; membrane potential was (-26.96 +/- 7.23) mV, decreased by 2.5%, all compared with that of NTR respectively. Iptakalim hydrochloride at the concentration of 0.1-100 micromol/L can significantly increased NTR potassium currents. Iptakalim hydrochloride 1-100 micromol/L can significantly increased RHR potassium currents.

CONCLUSIONMembrane capacitance, membrane current, membrane potential were decreased, I-V curves were shift downward, compared with that of NTR. Iptakalim hydrochloride might significantly increase NTR and RHR potassium currents.