N-palmitoyl glycine, a novel endogenous lipid that acts as a modulator of calcium influx and nitric oxide production in sensory neurons.
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.
Rimmerman
Neta
N
Department of Psychological and Brain Sciences, The Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN 47405, USA.
Bradshaw
Heather B
HB
Hughes
H Velocity
HV
Chen
Jay Shih-Chieh
JS
Hu
Sherry Shu-Jung
SS
McHugh
Douglas
D
Vefring
Eivind
E
Jahnsen
Jan A
JA
Thompson
Eric L
EL
Masuda
Kim
K
Cravatt
Benjamin F
BF
Burstein
Sumner
S
Vasko
Michael R
MR
Prieto
Anne L
AL
O'Dell
David K
DK
Walker
J Michael
JM
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
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