Fig. 2. Time course of effects of pretreatments and anoxia on contractile force in isolated human atrial trabeculae. Mean (± SD) percent of pretreatment (time 0) from the end of the treatment period (time 5 min) until the conclusion of the experiment. The treatment interval (anoxia and/or drug) is indicated by a banded bar, and the filled black bar denotes the interval of anoxia. (A ) Effects of 0.3 μm glibenclamide (Glib) and 10 nm 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) on anoxic preconditioning (APc). The time control is indicated by a solid line. (B  and C ) Preconditioning of muscles with 1.2% isoflurane (Isof) and 1% halothane (Hal). Values for the nonpreconditioned (dotted line) and APc (dashed line) groups are also shown for comparison.