title: 3H-delta 9-Tetrahydrocannabinol, 3H-cannabinol and 3H-cannabidiol: penetration and regional distribution in rat brain.
abstract: 3H-delta 9-Tetrahydrocannabinol (3H-delta 9-THC), 3H-cannabidiol (3H-CBD) and 3H-cannabinol (3H-CBN) were administered (1 mg/kg) to male rats which were decapitated either 0.5, 1, 15, 30 or 90 min later. The plasma concentration was similar for all cannabinoids throughout the time course. After 5 min greater than 80% of the plasma radioactivity in each treatment was due to metabolites. Radioactivity rapidly entered brain after the administration of 3H-CBD, 3H-CBN, and 3H-delta 9-THC. The concentrations of unchanged 3H-CBD aand 3H-CBN in whole brain were higher than that of 3H-delta 9-THC 5 min after administration. Regional distribution of radioactivity in the brain after 5 min was similar for all three cannabinoids, the only significant difference being in hypothalamus. Coadministration of 3H-delta 9-THC with a five-fold excess of either CBD or delta 9-THC did not produce any significant alteration in the levels of radioactivity in brain or plasma 5 min after their injection. The difference in behavioral activity of delta 9-THC, CBD and CBN cannot be explained by penetrability or regional distribution in the brain.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002185:Cannabidiol / Q000378:metabolism*; D002186:Cannabinoids / Q000378:metabolism*; D002187:Cannabinol / Q000378:metabolism*; D013759:Dronabinol / Q000378:metabolism*; D004347:Drug Interactions; D007700:Kinetics; D008297:Male; D051381:Rats; D013997:Time Factors
chemical_list: D002186:Cannabinoids; D002185:Cannabidiol; D013759:Dronabinol; D002187:Cannabinol