Fig. 3. Alteration in contractile force (expressed as mean ± SD percent of pretreatment force) of human atrial trabeculae at the end of the initial 5 min of the treatment episode for the specific intervention indicated. These data correspond to the first data point in figure 2. (Top ) No treatment was administered in the time control or anoxia groups. Effects of 0.3 μm glibenclamide (Glib) and 10 or 100 nm 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) on the 5-min treatment with anoxia or 10 nm N⁶-cyclohexyladenosine (CHA). (Bottom ) Effect of 1.2% isoflurane (Isof) and 1% halothane (Hal) on contractile force in the absence and presence of 0.3 μm Glib or 10 nm DPCPX. *P < 0.05 as compared with untreated control.