Characterisation of the rat cerebella CB1 receptor using SR141716A, a central cannabinoid receptor antagonist.
We describe the use of SR141716A, a central cannabinoid antagonist, in radioligand binding and adenylyl cyclase (AC) inhibition studies in rat cerebella membranes. The binding of [3H]SR141716A was dose-dependent and saturable, with Kd and Bmax of 0.61 +/- 0.12 nM and 1752 +/- 294 fmol/mg protein, respectively. Kinetic analysis of [3H]SR141716A binding afforded a Kd of 0.72 nM. In addition [3H]SR141716A was displaced dose-dependently by unlabelled SR141716A yielding a pKi of 8.37 +/- 0.07. Cannabinoid receptor agonists displaced [3H]SR141716A in a dose-dependent manner, (pKi) nabilone (8.29 +/- 0.08), WIN 55,212-2 (7.75 +/- 0.15), delta 9-tetrahydrocannabinol (7.29 +/- 0.21), delta 8-tetrahydrocannabinol (6.53 +/- 0.09) and anandamide (5.92 +/- 0.04). The affinity of anandamide was increased (6.26 +/- 0.13) by co-incubation with a serine protease inhibitor. A range of 13 commonly used non-cannabinoid ligands included at 100 microM were unable to displace [3H]SR141716A. WIN 55,212-2 inhibited basal cAMP formation dose-dependently with a pIC50 of 7.61 +/- 0.12 (24.3 nM) in an SR141716A (1 microM) reversible manner.
Hirst
R A
RA
University Department of Anaesthesia, Leicester Royal Infirmary, UK.
Almond
S L
SL
Lambert
D G
DG
D000818:Animals; D048588:Benzoxazines; D002186:Cannabinoids / Q000037:antagonists & inhibitors*; D002462:Cell Membrane; D002531:Cerebellum / Q000737:chemistry* / Q000378:metabolism; D013759:Dronabinol / Q000031:analogs & derivatives / Q000378:metabolism; D005260:Female; D008024:Ligands; D009025:Morpholines / Q000378:metabolism; D009281:Naphthalenes / Q000378:metabolism; D010880:Piperidines / Q000737:chemistry* / Q000378:metabolism; D011720:Pyrazoles / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011955:Receptors, Drug / Q000819:agonists / Q000037:antagonists & inhibitors*; D000077285:Rimonabant
D048588:Benzoxazines; D002186:Cannabinoids; D008024:Ligands; D009025:Morpholines; D009281:Naphthalenes; D010880:Piperidines; D011720:Pyrazoles; D011955:Receptors, Drug; C011941:nabilone; C035731:delta-8-tetrahydrocannabinol; C070417:(3R)-((2,3-dihydro-5-methyl-3-((4-morpholinyl)methyl)pyrrolo-(1,2,3-de)-1,4-benzoxazin-6-yl)(1-naphthalenyl))methanone; D013759:Dronabinol; D000077285:Rimonabant