title: CB1- and CB2-cannabinoid receptor-independent lipolysis induced by WIN 55,212-2 in male rat adipocytes.
abstract: The expression of genes encoding the cannabinoid CB(1) and CB(2) receptors and fatty acid amide hydrolase (FAAH) and the lipolytic activity of cannabinoid agonists were investigated in rat adipose tissue.RT-PCR studies indicated that the genes encoding CB(1) and CB(2) receptors and FAAH are not expressed in epididymal adipocytes. In functional studies, the non-selective cannabinoid receptor agonist WIN 55,212-2 concentration-dependently (0.01-30 micro M) induced glycerol release above baseline ( E(max) 96.1+/-6.2% of isoprenaline-induced lipolytic response). The selective CB(2) agonist JWH-015 (0.01-30 micro M) had no lipolytic activity while the endocannabinoid 2-arachidonoylglycerol and the stable anandamide derivative, R(+)-methanandamide had, only a weak lipolytic effect at the highest concentrations employed (10 and 30 micro M). The concentration/response relationship for WIN 55,212-2-mediated lipolytic activity, mimicked by the S(-)-enantiomer WIN 55,212-3, was shifted significantly to the right by the CB(1) antagonist AM 251 only at 10 micro M, but was not modified by the beta-adrenoceptor antagonist propranolol (1 micro M). The protein kinase inhibitor H-89, but not the two adenylyl cyclase inhibitors (+/-) N(6)- R-phenylisopropyladenosine (R-PIA, 1 micro M, a selective A(1) adenosine receptor agonist) or SQ 22,536 (50 micro M) significantly reduced the glycerol efflux induced by WIN 55,212-2. Our data suggest that the cannabinoid drug WIN 55,212-2 may exert lipolytic activity in male rat adipocytes via an intracellular mechanism, not activated by CB(1) or CB(2) receptor stimulation, significantly reversed by H-89 but not clearly linked to stimulation of adenylyl cyclase.
authors.affiliation: Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126, Pisa, Italy. paola.nieri@farm.unipi.it
authors.forename: Paola
authors.initials: P
authors.lastname: Nieri
authors.forename: Rosamiria
authors.initials: R
authors.lastname: Greco
authors.forename: Barbara
authors.initials: B
authors.lastname: Adinolfi
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Breschi
authors.forename: Enrica
authors.initials: E
authors.lastname: Martinotti
authors.forename: Carla
authors.initials: C
authors.lastname: Nannetti
authors.forename: Adriano
authors.initials: A
authors.lastname: Podestà
mesh_terms: D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism; D000581:Amidohydrolases / Q000096:biosynthesis; D000818:Animals; D048588:Benzoxazines; D004822:Epididymis / Q000166:cytology / Q000378:metabolism; D015870:Gene Expression; D005990:Glycerol / Q000378:metabolism; D066298:In Vitro Techniques; D008066:Lipolysis; D008297:Male; D009025:Morpholines / Q000737:chemistry / Q000494:pharmacology*; D009281:Naphthalenes / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D043884:Receptor, Cannabinoid, CB1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D043885:Receptor, Cannabinoid, CB2 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013237:Stereoisomerism; D000099252:Fatty Acid Amide Hydrolases
chemical_list: D000581:Amidohydrolases; D048588:Benzoxazines; D005990:Glycerol; D009025:Morpholines; D009281:Naphthalenes; D043884:Receptor, Cannabinoid, CB1; D043885:Receptor, Cannabinoid, CB2; D000099252:Fatty Acid Amide Hydrolases; C070417:(3R)-((2,3-dihydro-5-methyl-3-((4-morpholinyl)methyl)pyrrolo-(1,2,3-de)-1,4-benzoxazin-6-yl)(1-naphthalenyl))methanone