A, mean diameter ±s.e.m. for the 10, 60 and 100 mmHg final pressure groups during the initial step to 80 mmHg in Control (open bars) and H1152-containing (black bars) solution (values determined at times indicated in Fig. 5 by open and filled circles, respectively). Shaded bar is mean diameter in control conditions at 80 mmHg (data from Fig. 4). B, mean diameter ±s.e.m. prior to flash-freezing at points indicated in Fig. 5 by open and filled squares for control (open bars) and H1152-treated (black bars) arteries, respectively, at 10, 60 and 100 mmHg. Shaded bars are diameters in control and H1152-containing solution at 10, 60 and 100 mmHg (data from Fig. 4). *Significantly different (P < 0.05) from value in control solution.