The effect of cannabinoids on intestinal motility and their antinociceptive effect in mice

Summary

• 1

  After oral administration to mice, pethidine, Δ⁸-tetrahydrocannabinol (THC), Δ⁹-THC, a cannabis extract and cannabinol had a dose-dependent antinociceptive effect when measured by the hot-plate method. Cannabidiol was inactive at 30 mg/kg. Δ⁸-THC, Δ⁹-THC and pethidine did not differ significantly in potency, but Δ⁹-THC was 6·5 times more active than cannabinol.

• 2

  After oral administration, three different cannabis extracts, Δ⁸-THC, Δ⁹-THC and morphine produced dose-dependent depressions of the passage of a charcoal meal in mice. Δ⁸-THC and Δ⁹-THC were equipotent and were about five times less potent than morphine. Cannabidiol was inactive up to 30 mg/kg. The effect of the three cannabis extracts on intestinal motility could be accounted for by their Δ⁹-THC content.

• 3

  The antinociceptive effect of pethidine and the effect of morphine on intestinal motility were antagonized by nalorphine whilst the effects of the cannabis extracts and the pure cannabinoids were not.

• 4

  From these results it is concluded that although cannabis and the narcotics share several common pharmacological properties, the mode of action of each is pharmacologically distinct.