Fig. 2. Effect of potassium-channel blockade on isoflurane-mediated vasodilation in porcine coronary arterioles. Maximal dilation (36 ± 4 μm) was determined by exposing each vessel to 10−4m sodium nitroprusside. Asterisks indicate a significant (P < 0.05) increase in arteriolar internal diameter as compared with vessels before isoflurane exposure. Plus signs indicate a significant difference in isoflurane-mediated vasodilation between control and glibenclamide-treated vessels at each isoflurane concentration. Baseline values for vessel ID in the control, glibenclamide, and iberiotoxin groups were 77 ± 7, 74 ± 6, and 82 ± 10 μm, respectively. Vertical bars represent 1 ± SEM.