Fig. 3

Effect of dihydroergotamine (DHE) on the morphine analgesia. a Effect of dihydroergotamine (100 μg/kg) in the tail-flick test, and b effect of dihydroergotamine in the hot-plate test. Dihydroergotamine in combination with morphine produce a significant increase in % MPE in both the tail-flick (p < 0.05; a) and hot-plate assays (p < 0.05; b) as compared to the morphine-treated rats. Each point represents the mean ± SEM of percent of maximal possible effect (% MPE) for 7 rats. *p < 0.05 compared to the morphine-treated group and **p < 0.01 compared to saline-treated group