Inhibitory effects of certain enantiomeric cannabinoids in the mouse vas deferens and the myenteric plexus preparation of guinea-pig small intestine.
1. The psychoactive cannabinoids (-)-delta 9-tetrahydrocannabinol ((-)-delta 9-THC) and the 1,1-dimethyl-heptyl homologue of (-)-11-hydroxy-delta 8-tetrahydrocannabinol ((-)-DMH) both inhibited electrically-evoked contractions of the mouse isolated vas deferens and the myenteric plexus-longitudinal muscle preparation of the guinea-pig small intestine. 2. Concentrations of (-)-delta 9-THC and (-)-DMH that decreased twitch heights by 50% were 6.3 and 0.15 nM respectively in the mouse vas deferens and 60 nM and 1.4 nM respectively in the myenteric plexus preparation. (-)-DMH was about 40 times more potent than (-)-delta 9-THC in both preparations, supporting the notion that their mode of action in each tissue is the same. 3. The psychically inactive cannabinoid, (+)-DMH, had no inhibitory effect in the mouse vas deferens at a concentration of 30 nM, showing it to be at least 1000 times less potent than (-)-DMH. In the myenteric plexus preparation, (+)-DMH was about 500 times less potent than its (-)-enantiomer. 4. The inhibitory effects of sub-maximal concentrations of (-)-delta 9-THC were not attenuated by 300 nM naloxone. 5. The findings that (-)-delta 9-THC and (-)-DMH are highly potent as inhibitors of the twitch response of the mouse vas deferens and guinea-pig myenteric plexus preparation and that DMH shows considerable stereoselectivity suggest that the inhibitory effects of cannabinoids in these preparations are mediated by cannabinoid receptors.
Pertwee
R G
RG
Division of Pharmacology, School of Biomedical Sciences, Marischal College, University of Aberdeen.
Stevenson
L A
LA
Elrick
D B
DB
Mechoulam
R
R
Corbett
A D
AD
D000818:Animals; D002186:Cannabinoids / Q000737:chemistry / Q000494:pharmacology*; D013759:Dronabinol / Q000031:analogs & derivatives / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D009197:Myenteric Plexus / Q000187:drug effects*; D013237:Stereoisomerism; D014649:Vas Deferens / Q000187:drug effects*
D002186:Cannabinoids; C033189:dimethyl-heptyl tetrahydrocannabinol; D013759:Dronabinol