title: The endocannabinoid 2-arachidonylglycerol decreases the immunological activation of Guinea pig mast cells: involvement of nitric oxide and eicosanoids.
abstract: The antigen-induced release of histamine from sensitized guinea pig mast cells was dose-dependently reduced by endogenous (2-arachidonylglycerol; 2AG) and exogenous [(1R,3R,4R)-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-4-(3-hydroxypropyl)cyclohexan-1-ol (CP55,940)] cannabinoids. The inhibitory action afforded by 2AG and CP55,940 was reversed by N-[(1S)-endo-1,3,3-trimethylbicyclo[2.2.1]heptan-2-yl]5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)pyrazole-3-carboxamide (SR144528), a selective cannabinoid 2 (CB(2)) receptor antagonist, and left unchanged by the selective CB(1) antagonist N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251). The inhibitory action of 2AG and CP55,940 was reduced by the unselective nitric-oxide synthase (NOS) inhibitor N-monomethyl-L-arginine methylester (l-NAME) and reinstated by L-arginine, the physiological substrate. The inhibitory action of 2AG and CP55,940 was also reduced by the unselective cyclooxygenase (COX) inhibitor indomethacin and the selective COX-2 blocker rofecoxib. Both 2AG and CP55,940 significantly increased the production of nitrite from mast cells, which was abrogated by L-NAME and N-(3-(aminomethyl)benzyl)acetamidine (1400W), a selective inducible NOS (iNOS) inhibitor. Nitrite production consistently paralleled a CP55,940-induced increase in the expression of iNOS protein in mast cells. Both 2AG and CP55,940 increased the generation of prostaglandin E(2) from mast cells, which was abrogated by indomethacin and rofecoxib and parallel to the CP55,940-induced expression of COX-2 protein. Mast cell challenge with antigen was accompanied by a net increase in intracellular calcium levels. Both cannabinoid receptor ligands decreased the intracellular calcium levels, which were reversed by SR144528 and l-NAME. In unstimulated mast cells, both ligands increased cGMP levels. The increase was abrogated by SR144528, l-NAME, indomethacin, and rofecoxib. Our results suggest that 2AG and CP55,940 decreased mast cell activation in a manner that is susceptible to a CB(2) receptor antagonist and to inhibition of nitric oxide and prostanoid pathways.
authors.affiliation: Department of Preclinical and Clinical Pharmacology, University of Florence, Viale G. Pier-accini, n 6, 50139 Florence, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Vannacci
authors.forename: Lucia
authors.initials: L
authors.lastname: Giannini
authors.forename: Maria Beatrice
authors.initials: MB
authors.lastname: Passani
authors.forename: Annamaria
authors.initials: A
authors.lastname: Di Felice
authors.forename: Simone
authors.initials: S
authors.lastname: Pierpaoli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Zagli
authors.forename: Ornella
authors.initials: O
authors.lastname: Fantappiè
authors.forename: Roberto
authors.initials: R
authors.lastname: Mazzanti
authors.forename: Emanuela
authors.initials: E
authors.lastname: Masini
authors.forename: Pier Francesco
authors.initials: PF
authors.lastname: Mannaioni
mesh_terms: D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology*; D015153:Blotting, Western; D063385:Cannabinoid Receptor Modulators / Q000494:pharmacology*; D003511:Cyclohexanols / Q000494:pharmacology; D015777:Eicosanoids / Q000502:physiology*; D063388:Endocannabinoids; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005989:Glycerides / Q000494:pharmacology*; D006168:Guinea Pigs; D007109:Immunity / Q000187:drug effects*; D007166:Immunosuppressive Agents / Q000494:pharmacology; D008297:Male; D008407:Mast Cells / Q000187:drug effects* / Q000276:immunology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D043885:Receptor, Cannabinoid, CB2 / Q000378:metabolism
chemical_list: D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D003511:Cyclohexanols; D015777:Eicosanoids; D063388:Endocannabinoids; D004791:Enzyme Inhibitors; D005989:Glycerides; D007166:Immunosuppressive Agents; D043885:Receptor, Cannabinoid, CB2; D009569:Nitric Oxide; C054649:3-(2-hydroxy-4-(1,1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol; C094503:glyceryl 2-arachidonate; D019331:NG-Nitroarginine Methyl Ester