title: Interactions among the cannabinoids in the antagonism of the abdominal constriction response in the mouse.
abstract: The ability of delta 9-tetrahydrocannabinol (THC), cannabinol (CBN), cannabidiol (CBD), 11-OH THC and 8 alpha, 11-diOH THC to antagonise the abdominal constriction response in the mouse induced by formic acid, phenylquinone, 5-hydroxytryptamine, prostaglandin E1 (PGE1) and bradykinin was tested. THC was an effective antagonist against all nociceptive agents with an ED50 in all cases between 1.0 and 2.6 mg/kg. CBN, while also effective against all nociceptive agents, was less potent than THC, with an ED50 range between 46.2 and 112.5 mg/kg. CBD in doses as high as 200 mg/kg was without effect. Using PGE1 as the nociceptive agent, 11-OH THC was equipotent to THC while 8 alpha, 11-diOH THC was inactive. Naloxone, while able to antagonise the antinociceptive effect of morphine against formic acid-induced writhing, did not reverse the antinociceptive effects of THC. There were no pharmacological interactions between THC, CBD and CBN.
mesh_terms: D000009:Abdominal Muscles / Q000187:drug effects; D000700:Analgesics; D000818:Animals; D002186:Cannabinoids / Q000494:pharmacology*; D013759:Dronabinol / Q000494:pharmacology; D004347:Drug Interactions; D005561:Formates / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology; D011458:Prostaglandins E / Q000494:pharmacology
chemical_list: D000700:Analgesics; D002186:Cannabinoids; D005561:Formates; D011458:Prostaglandins E; D009270:Naloxone; D013759:Dronabinol