Figure 4.

Electrical field stimulation (EFS)-induced contractions of the isolated ileum of control mice: effect of salvinorin A (10⁻¹¹–10⁻⁶ M) alone (vehicle) or in the presence of the cannabinoid CB₁ receptor antagonist rimonabant (3 × 10⁻⁸  M) or the KOR antagonist nor-binaltorphimine (nor-bin, 3 × 10⁻⁸ M). Each point represents mean±s.e.mean of 8–10 experiments. ^**P<0.01 and ^***P<0.001 vs vehicle (i.e. the rimonabant and nor-binaltorphimine concentration–response curves were significantly different from the vehicle curve).