title: 12-hydroxyeicosatetrenoate (12-HETE) attenuates AMPA receptor-mediated neurotoxicity: evidence for a G-protein-coupled HETE receptor.
abstract: 12-hydroxyeicosatetraenoic acid (12-HETE) is a neuromodulator that is synthesized during ischemia. Its neuronal effects include attenuation of calcium influx and glutamate release as well as inhibition of AMPA receptor (AMPA-R) activation. Because 12-HETE reduces ischemic injury in the heart, we examined whether it can also reduce neuronal excitotoxicity. When treated with 12-(S)HETE, cortical neuron cultures subjected to AMPA-R-mediated glutamate toxicity suffered up to 40% less damage than untreated cultures. The protective effect of 12-(S)HETE was concentration-dependent (EC50 = 88 nm) and stereostructurally selective. Maximal protection was conferred by 300 nm 12-(S)HETE; 300 nm 15-(S)HETE was similarly protective, but 300 nm 5-(S)HETE was less effective. The chiral isomer 12-(R)HETE offered no protection; neither did arachidonic acid or 12-(S)hydroperoxyeicosatetraenoic acid. Excitotoxicity was calcium-dependent, and 12-(S)HETE was demonstrated to protect by inactivating N and L (but not P) calcium channels via a pertussis toxin-sensitive mechanism. Calcium imaging demonstrated that 12-(S)HETE also attenuates glutamate-induced calcium influx into neurons via a pertussis toxin-sensitive mechanism, suggesting that it acts via a G-protein-coupled receptor. In addition, 12-(S)HETE stimulates GTPgammaS binding (indicating G-protein activation) and inhibits adenylate cyclase in forskolin-stimulated cultures over the same concentration range as it exerts its anti-excitotoxic and calcium-influx attenuating effects. These studies demonstrate that 12-(S)HETE can protect neurons from excitotoxicity by activating a G(i/o)-protein-coupled receptor, which limits calcium influx through voltage-gated channels.
authors.affiliation: Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA. ahampson@cortexpharm.com
authors.forename: Aidan J
authors.initials: AJ
authors.lastname: Hampson
authors.forename: Maurizio
authors.initials: M
authors.lastname: Grimaldi
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000494:pharmacology*; D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D001581:Benzothiadiazines / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D018698:Glutamic Acid / Q000633:toxicity; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008954:Models, Biological; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000494:pharmacology; D037342:Pertussis Toxin; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000378:metabolism*; D018055:Receptors, Eicosanoid / Q000378:metabolism*; D018092:Kainic Acid Receptors / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D001581:Benzothiadiazines; D015220:Calcium Channels; D002614:Chelating Agents; D016291:Dizocilpine Maleate; D018691:Excitatory Amino Acid Antagonists; D019204:GTP-Binding Proteins; D018698:Glutamic Acid; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D007770:L-Lactate Dehydrogenase; D018696:Neuroprotective Agents; D037342:Pertussis Toxin; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D018091:Receptors, AMPA; D018055:Receptors, Eicosanoid; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate; D010566:Virulence Factors, Bordetella; C066652:12-hydroxyeicosatetraenoic acid receptor; C004639:cyclothiazide