Electrospray ionization mass spectrometric method for the determination of cannabinoid precursors: N-acylethanolamine phospholipids (NAPEs).
N-Acylethanolamine phospholipids (NAPEs) serve as endogenous precursors of N-acylethanolamines (NAEs), e.g. N-arachidonoylethanolamine (anandamide) and N-palmitoylethanolamine that are endogenous ligands of cannabinoid receptors. Under physiological conditions, NAPE is found in very low concentrations in mammalian tissue (3-12 nmol g(-1)). However, pathophysiological conditions may increase the endogenous NAPE levels, which again may cause an increase in endocannabinoid concentrations. This paper presents a simple and selective method for the determination of NAPE standards using negative electrospray ionization mass spectrometry (ESI-MS). The procedure provides complete positioning of all acyl and alkenyl groups contained in each NAPE species. The calibration curve for standard NAPE was linear over the range 100 fmol-50 pmol (0.1-50 ng) per injection. The lower limit of detection (signal-to-noise ratio of 3) was 100 fmol, implying that this method is superior to previous methods for the determination of NAPE. These results suggest that this ESI-MS method can be used to identify and quantify NAPE species in mammalian tissues and provide information on the corresponding NAEs to be released from the endogenous NAPE pool.
Hansen
H H
HH
Department of Pharmacology, Royal Danish School of Pharmacy, 2 Universitetsparken, DK-2100 Copenhagen, Denmark. hhh@mail.dfh.dk
Hansen
S H
SH
Bjørnsdottir
I
I
Hansen
H S
HS
D000818:Animals; D001921:Brain / Q000378:metabolism; D063385:Cannabinoid Receptor Modulators; D002186:Cannabinoids / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism; D002417:Cattle; D004983:Ethanolamines / Q000032:analysis / Q000737:chemistry*; D008024:Ligands; D013058:Mass Spectrometry / Q000379:methods; D015394:Molecular Structure; D010743:Phospholipids / Q000032:analysis / Q000737:chemistry*; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000378:metabolism
D063385:Cannabinoid Receptor Modulators; D002186:Cannabinoids; D004983:Ethanolamines; D008024:Ligands; C022203:N-acylethanolamines; D010743:Phospholipids; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug