Effect of the Rho kinase inhibitors Y-27632 and RKI-1447 (RKI) on starting afferent arteriole diameters. The effect of Y-27632 (1, 5, and 10 µM, A) and RKI-1447 (0.1, 1, and 10 µM, B) on the starting diameter of afferent arterioles compared with control is shown. Data are expressed as a percentage of the starting diameter. Values are expressed as means ± SE; n, number of kidneys. *P < 0.05 vs. baseline in the same group.