Cannabinoid-induced lower lip retraction in rats.
Lower lip retraction (LLR) in rats has been described as a distinctive effect of 5-HT To pharmacologically characterize cannabinoid-induced LLR in rats. Lower lip retraction was scored using a 3-point scale for up to 6 h after injection of the cannabinoid agonists Δ All three cannabinoid agonists produced LLR. Effects of AM2389 were attenuated by both rimonabant and WAY100635 whereas effects of 8-OH-DPAT were antagonized by WAY 100635 but not by rimonabant. Pretreatment with 1 mgkg Δ Cannabinoid agonists produce LLR in rats, an effect heretofore ascribed only to activity at 5-HT