Fig. 3 . Twitch force and resting tension for ventricular preparations from Atlantic cod subjected to anoxia and reoxygenation, and treated with agents to affect K_ATP-channel activity. Arrows indicate times at which anoxia was induced (20 min) and when preparations were reoxygenated (55 min). (A) DMSO treated (diamonds) (N=13). (B) Glibenclamide-treated (squares) (N=8). (C) Diazoxide treated (hexagons) (N=5). (D) 5HD-treated (triangles) (N=5). `b' indicates a significant change from measurements within the treatment taken 5 min beforehand.