Figure 4.

Effect of K⁺-free solution on the hyperpolarization of endothelial cells from rat aorta produced by acetylcholine. (a) Original tracing showing the influence of external K⁺ substitution on the resting membrane potential and acetylcholine-induced hyperpolarization of endothelial cells. (b) Graphical representation of the time dependency of the effect of K⁺-free solution on the mean changes in membrane potential evoked by 2 μM acetylcholine. The changes in membrane potential were calculated as the difference between the membrane potential values before and after acetylcholine administration. Numbers associated with bar plot indicate the number of aorta preparations.