N-Arachidonyl-glycine inhibits the glycine transporter, GLYT2a.
N-arachidonyl-glycine is one of a series of N-arachidonyl-amino acids that are derived from arachidonic acid. N-arachidonyl-glycine is produced in a wide range of tissues with greatest abundance in the spinal cord. Here we report that N-arachidonyl-glycine is a reversible and non-competitive inhibitor of glycine transport by GLYT2a, but has little effect on glycine transport by GLYT1b or gamma-amino butyric acid transport by GAT1. It has previously been reported that the activity of GLYT2a is down-regulated by protein kinase C and therefore we investigated whether the actions of N-arachidonyl-glycine on GLYT2a are mediated by second messenger systems that lead to the activation of protein kinase C. However, the protein kinase C inhibitor, staurosporine, had no effect on the actions of N-arachidonyl-glycine on GLYT2a. Thus, the actions of N-arachidonyl-glycine are likely to be mediated by a direct interaction with the transporter. We have further defined the pharmacophore by investigating the actions of other N-arachidonyl amino acids as well as the closely related compounds arachidonic acid, anandamide and R1-methanandamide. Arachidonic acid, anandamide and R1-methanandamide have no effect on glycine transport, but N-arachidonyl-l-alanine has similar efficacy at GLYT2a to N-arachidonyl-glycine, and N-arachidonyl-gamma-amino butyric acid is less efficacious. These observations define a novel recognition site for the N-arachidonyl amino acids.
Wiles
Amy L
AL
Department of Pharmacology, Bosch Institute, University of Sydney, Sydney, New South Wales, Australia.
Pearlman
Rhonda-Jo
RJ
Rosvall
Mari
M
Aubrey
Karin R
KR
Vandenberg
Robert J
RJ
D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology*; D004247:DNA / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D063388:Endocannabinoids; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D050485:GABA Plasma Membrane Transport Proteins / Q000378:metabolism; D058805:GABA Uptake Inhibitors; D005998:Glycine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D050487:Glycine Plasma Membrane Transport Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D009865:Oocytes / Q000378:metabolism; D018408:Patch-Clamp Techniques; D053284:Polyunsaturated Alkamides / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D014982:Xenopus laevis
D001095:Arachidonic Acids; D063388:Endocannabinoids; D004791:Enzyme Inhibitors; D050485:GABA Plasma Membrane Transport Proteins; D058805:GABA Uptake Inhibitors; D050487:Glycine Plasma Membrane Transport Proteins; C465623:N-arachidonylglycine; D053284:Polyunsaturated Alkamides; C493271:SLC6A5 protein, human; D004247:DNA; D019311:Staurosporine; D005998:Glycine; C078814:anandamide