title: The pharmacological activity of the fatty acid conjugate 11-palmitoyloxy-delta 9-tetrahydrocannabinol.
abstract: A long-retained cannabinoid metabolite has been detected in rat tissue after intravenous administration of delta 9-tetrahydrocannabinol (THC) and has been identified as a fatty acid conjugate of psychoactive 11-hydroxy-delta 9-tetrahydrocannabinol (11-OH-delta 9-THC) and palmitic acid. The objective of these studies was to determine if this compound, 11-palmitoyloxy-delta 9-tetrahydrocannabinol (11-palm-delta 9-THC) is pharmacologically active. Intravenously injected 11-palm-delta 9-THC decreased thermal sensitivity and induced catalepsy in rats, responses similar to those produced by 11-OH-delta 9-THC, but less pronounced and more delayed. To further characterize the response, animals were intracisternally injected with 11-OH-delta 9-THC or 11-palm-delta 9-THC. Catalepsy and decreased thermal sensitivity were seen in the 11-OH-delta 9-THC and 11-palm-delta 9-THC groups, and again, 11-OH-delta 9-THC appeared to be the more potent of the two cannabinoids. In contrast to the intravenous study, 11-palm-delta 9-THC-induced effects were seen soon after treatment and appeared to be fully developed by the first test time (15 min). The intracisternal results suggest that 11-palm-delta 9-THC itself is active; however, since it is known that the fatty acid conjugate is hydrolyzed in vivo to 11-OH-delta 9-THC in the rat, the possibility remains that the effects of 11-palm-delta 9-THC are due to metabolic conversion to 11-OH-delta 9-THC.
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002186:Cannabinoids; D002187:Cannabinol / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D002375:Catalepsy / Q000139:chemically induced; D002395:Catecholamines / Q000032:analysis; D007275:Injections, Intravenous; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D013574:Synaptosomes / Q000187:drug effects* / Q000378:metabolism
chemical_list: D002186:Cannabinoids; D002395:Catecholamines; C049600:11-palmitoyloxy-delta(9)-tetrahydrocannabinol; D002187:Cannabinol