Endothelium-dependent relaxation is known to be depressed in arteries of SHR. We studied acetylcholine (Ach) -induced electrical responses of intact aortic endothelial cells from WKY rats and SHR using perforated patch-clamp method. Resting Em averaged -44,3±1,1 mV and -35,2±1,2 mV for WKY and SHR, respectively. Application of K+ free solution depolarized endothelium by 11,0±0,7 mV and 7,5±1,3 mV (р<0,05) for WKY and SHR, respectively, showing inhibition of endothelial electrogenic Na+/K+ pump in SHR. The amplitude of Ach-induced hyperpolarization for WKY and SHR was 19±1 mV and 25±1 mV, respectively. However, the rate of its recovery was different within particular preparation taken from SHR whereas it was very similar within particular preparation from WKY rats, showing alterations in intercellular signaling in endothelium of SHR.