[The role of Na+,K+ ATPase in electrogenicity of the aortic endothelial cells].

The role of Na pump in the regulation of the membrane potential of endothelial cells of rat isolated aorta at rest and during stimulation by acetylcholine was investigated. Inhibition of Na pump by 500 mcM ouabain and potassium-free solution depolarized endothelial cells by 11 mV. Na pump reactivation caused by potassium restoration hyperpolarized endothelium by 18 mV, this hyperpolarization was sensitive to 500 mcM ouabain. Potassium-free solution and ouabain attenuated the duration of the acetylcholine-evoked hyperpolarization. The results presented demonstrate that the sustained hyperpolarization of endothelial cells to acetylcholine in rat aorta may be partially mediated by Na pump stimulation.