The effects of cannabidiol and tetrahydrocannabinol on motion-induced emesis in Suncus murinus

The effect of cannabinoids on motion-induced emesis is unknown. The present study investigated the action of phytocannabinoids against motion-induced emesis in Suncus murinus. Suncus murinus were injected intraperitoneally with either cannabidiol (CBD) (0.5, 1, 2, 5, 10, 20 and 40 mg/kg), Δ⁹-tetrahydrocannabinol (Δ⁹-THC; 0.5, 3, 5 and 10 mg/kg) or vehicle 45 min. before exposure to a 10-min. horizontal motion stimulus (amplitude 40 mm, frequency 1 Hz). In further investigations, the CB₁ receptor antagonist, N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4- dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM 251; 5 mg/kg), was injected 15 min. prior to an injection of Δ⁹-THC (3 mg/kg). The motion stimulus was applied 45 min. later. The number of emetic episodes and latency of onset to the first emetic episode were recorded. Pre-treatment with the above doses of CBD did not modify the emetic response to the motion stimulus as compared to the vehicle-treated controls. Application of the higher doses of Δ⁹-THC induced emesis in its own right, which was inhibited by AM 251. Furthermore, pre-treatment with Δ⁹-THC dose-dependently attenuated motion-induced emesis, an effect that was inhibited by AM 251. AM 251 neither induced an emetic response nor modified motion-induced emesis. The present study indicates that Δ⁹-THC, acting via the CB₁ receptors, is anti-emetic to motion, and that CBD has no effect on motion-induced emesis in Suncus murinus.