Figure 6. To examine the pharmacologic antagonism of the effects of ouabain (O; 2 [micro sign]g) and ouabain (1 [micro sign]g)-morphine (M; 2 [micro sign]g), atropine (A; 5 [micro sign]g) was administered intrathecally 10 min before the administration of the agonists. Each bar represents the mean +/− SD from five rats. *P < 0.05;**P < 0.01, AUC = area under the time-response curve.