Fig. 2. Effects of ketamine on vascular responses to either KCl or norepinephrine (NE) in the endothelium-denuded (−E), fura-2–loaded strips. (A ) Effects of ketamine (0.001∼3 mm) on the KCl (40 mm)-induced increases in R340/380([Ca2+]i) and force. (a ) Typical example; (b ) the analyzed data (n = 7). The closed and open circles indicate the data on R340/380and force, respectively. The IC50values for the ketamine-induced inhibitions of the increases in R340/380and force caused by KCl are 0.33 and 0.13 mm, respectively. *P < 0.05 versus control (100%) within each group. (B ) Effects of ketamine (0.001∼3 mm) on increases in [Ca2+]i (R340/380, closed circles) and force (open circles) caused by norepinephrine. The IC50values for the ketamine-induced inhibitions of the increases in R340/380and force caused by norepinephrine are 0.23 and 0.22 mm, respectively. n = 6. *P < 0.05 versus control (100%) within each group.