title: N-palmitoyl glycine, a novel endogenous lipid that acts as a modulator of calcium influx and nitric oxide production in sensory neurons.
abstract: N-arachidonoyl glycine is an endogenous arachidonoyl amide that activates the orphan G protein-coupled receptor (GPCR) GPR18 in a pertussis toxin (PTX)-sensitive manner and produces antinociceptive and antiinflammatory effects. It is produced by direct conjugation of arachidonic acid to glycine and by oxidative metabolism of the endocannabinoid anandamide. Based on the presence of enzymes that conjugate fatty acids with glycine and the high abundance of palmitic acid in the brain, we hypothesized the endogenous formation of the saturated N-acyl amide N-palmitoyl glycine (PalGly). PalGly was partially purified from rat lipid extracts and identified using nano-high-performance liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry. Here, we show that PalGly is produced after cellular stimulation and that it occurs in high levels in rat skin and spinal cord. PalGly was up-regulated in fatty acid amide hydrolase knockout mice, suggesting a pathway for enzymatic regulation. PalGly potently inhibited heat-evoked firing of nociceptive neurons in rat dorsal horn. In addition, PalGly induced transient calcium influx in native adult dorsal root ganglion (DRG) cells and a DRG-like cell line (F-11). The effect of PalGly on the latter cells was characterized by strict structural requirements, PTX sensitivity, and dependence on the presence of extracellular calcium. PalGly-induced calcium influx was blocked by the nonselective calcium channel blockers ruthenium red, 1-(beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl)-1H-imidazole (SK&F96365), and La3+. Furthermore, PalGly contributed to the production of NO through calcium-sensitive nitric-oxide synthase enzymes present in F-11 cells and was inhibited by the nitric-oxide synthase inhibitor 7-nitroindazole.
authors.affiliation: Department of Psychological and Brain Sciences, The Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN 47405, USA.
authors.forename: Neta
authors.initials: N
authors.lastname: Rimmerman
authors.forename: Heather B
authors.initials: HB
authors.lastname: Bradshaw
authors.forename: H Velocity
authors.initials: HV
authors.lastname: Hughes
authors.forename: Jay Shih-Chieh
authors.initials: JS
authors.lastname: Chen
authors.forename: Sherry Shu-Jung
authors.initials: SS
authors.lastname: Hu
authors.forename: Douglas
authors.initials: D
authors.lastname: McHugh
authors.forename: Eivind
authors.initials: E
authors.lastname: Vefring
authors.forename: Jan A
authors.initials: JA
authors.lastname: Jahnsen
authors.forename: Eric L
authors.initials: EL
authors.lastname: Thompson
authors.forename: Kim
authors.initials: K
authors.lastname: Masuda
authors.forename: Benjamin F
authors.initials: BF
authors.lastname: Cravatt
authors.forename: Sumner
authors.initials: S
authors.lastname: Burstein
authors.forename: Michael R
authors.initials: MR
authors.lastname: Vasko
authors.forename: Anne L
authors.initials: AL
authors.lastname: Prieto
authors.forename: David K
authors.initials: DK
authors.lastname: O'Dell
authors.forename: J Michael
authors.initials: JM
authors.lastname: Walker
mesh_terms: D000581:Amidohydrolases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000906:Antibodies; D001549:Benzamides / Q000494:pharmacology; D001923:Brain Chemistry; D002118:Calcium / Q000378:metabolism*; D002219:Carbamates / Q000494:pharmacology; D002460:Cell Line; D003433:Crosses, Genetic; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005727:Ganglia, Spinal / Q000737:chemistry / Q000166:cytology; D005998:Glycine / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009475:Neurons, Afferent / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D009619:Nociceptors / Q000187:drug effects; D010169:Palmitic Acids / Q000737:chemistry / Q000494:pharmacology*; D037342:Pertussis Toxin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D043882:Receptors, Cannabinoid / Q000378:metabolism*; D014018:Tissue Distribution; D015854:Up-Regulation; D000099252:Fatty Acid Amide Hydrolases
chemical_list: D000581:Amidohydrolases; D000906:Antibodies; D001549:Benzamides; D002118:Calcium; D002219:Carbamates; D004791:Enzyme Inhibitors; D005998:Glycine; D009569:Nitric Oxide; D010169:Palmitic Acids; D037342:Pertussis Toxin; D043882:Receptors, Cannabinoid; D000099252:Fatty Acid Amide Hydrolases; C588261:GPR18 protein, rat; C500528:cyclohexyl carbamic acid 3'-carbamoylbiphenyl-3-yl ester; C095773:N-palmitoylglycine