title: Ether-linked analogue of 2-arachidonoylglycerol (noladin ether) was not detected in the brains of various mammalian species.
abstract: 2-Eicosa-5',8',11',14'-tetraenylglycerol (2-AG ether, HU310, noladin ether) is a metabolically stable ether-linked analogue of 2-arachidonoylglycerol (2-AG), an endogenous cannabinoid receptor ligand. 2-AG ether has been used as a valuable experimental tool by a number of investigators. Recently, several groups reported that 2-AG ether is present in mammalian brains. We examined in detail whether 2-AG ether actually exists in the brains of various mammalian species. We found that 2-AG ether is not present, at least in an appreciable amount, in the rat brain by gas chromatography-mass spectrometry analysis and fluorometric high performance liquid chromatography analysis. The level of 2-AG ether in the rat brain was below 0.2 pmol/g brain, if at all present. Similar results were obtained for the mouse brain, hamster brain, guinea-pig brain and pig brain. The fact that 2-AG ether was not detected in the brains of various mammalian species is consistent with the fact that an ether bond is formed through enzymatic replacement of the fatty acyl moiety of 1-acyl dihydroxyacetone phosphate by a fatty alcohol, the resultant 1-O-alkyl dihydroxyacetone phosphate being a common intermediate of the biosynthesis of ether-linked lipids in mammalian tissues. It is rather questionable whether 2-AG ether is present in appreciable amounts in the brain and acts as an 'endogenous' cannabinoid receptor ligand.
authors.affiliation: Department of Hygienic Chemistry and Nutrition, Faculty of Pharmaceutical Sciences, Teikyo University, Kanagawa, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Oka
authors.forename: Akiko
authors.initials: A
authors.lastname: Tsuchie
authors.forename: Akira
authors.initials: A
authors.lastname: Tokumura
authors.forename: Mayumi
authors.initials: M
authors.lastname: Muramatsu
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Suhara
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takayama
authors.forename: Keizo
authors.initials: K
authors.lastname: Waku
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sugiura
mesh_terms: D000818:Animals; D001095:Arachidonic Acids; D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D063388:Endocannabinoids; D005989:Glycerides / Q000032:analysis*; D005995:Glyceryl Ethers / Q000032:analysis; D006168:Guinea Pigs; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D051379:Mice; D051381:Rats; D013552:Swine
chemical_list: D001095:Arachidonic Acids; D063388:Endocannabinoids; D005989:Glycerides; D005995:Glyceryl Ethers; C424442:noladin ether; C094503:glyceryl 2-arachidonate