Fig. 3. Effects of glibenclamide (5 µmol l^–1), a K_ATP channel blocker, and L-NAME (50 µmol l^–1), an inhibitor of nitric oxide synthase (NOS), on the percentage change in action potential duration at 90% repolarization (APD₉₀) induced by hypoxia in goldfish ventricle (N=4). Hypoxia-induced APD₉₀ shortening was eliminated by simultaneous exposure to either glibenclamide or L-NAME. Values are mean change ± 1 S.E.M.