Cannabinoid Receptors

Cannabinoid receptors are activated by cannabinoids, generated naturally inside the body (endocannabinoids) or introduced into the body as cannabis or a related synthetic compound.

Separation between the therapeutically undesirable psychotropic effects, and the clinically desirable ones, however, has not been reported with agonists that bind to cannabinoid receptors. THC, as well as the two major endogenous compounds identified so far that bind to the cannabinoid receptors —anandamide and 2-arachidonylglycerol (2-AG)— produce most of their effects by binding to both the CB₁ and CB₂ cannabinoid receptors. While the effects mediated by CB₁, mostly in the central nervous system, have been thoroughly investigated, those mediated by CB₂ are not equally well defined.

Inhibition of gastrointestinal activity has been observed after administration of Δ^9-THC, or of anandamide. This effect has been assumed to be CB₁-mediated since the specific CB₁antagonist SR 141716A (Rimonabant) blocks the effect. Another report, however, suggests that inhibition of intestinal motility may also have a CB₂-mediated component.^[23]

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Cannabinoids are well known for their cardiovascular activity.

Cannabis sativa preparations have been known as therapeutic agents against various diseases for millennia.^[33] The native active constituent, Δ^{9-tetrahydrocannabinol} (Δ^9-THC) was found to be the principal mediator of the effects of cannabis.^[34] Synthetic Δ⁹-THC is prescribed today under the generic name Dronabinol, to treat vomiting and for enhancement of appetite, mainly in AIDS patients.

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