N-methyl-D-aspartate (NMDA) glutamate receptor-ion channels in the brain are important mediators of the behavioral effects of alcohol. Although alcohol is known to inhibit NMDA receptors by influencing ion channel gating, its molecular site of action and the mechanism underlying this effect have not been established. Previous studies have pointed to a role of the membrane-spanning domains of neurotransmitter-gated ion channels in the actions of alcohol. Results from this laboratory have shown that a conserved methionine residue (Met823) in the fourth membrane-associated (M) domain of the NMDA receptor NR2A subunit profoundly influences ion channel gating. Recent evidence obtained in this laboratory has shown that NR2A(Met823) also affects alcohol sensitivity of the receptor in a manner that is consistent with a site of alcohol action, and that adjacent residues may also influence both ion channel gating and alcohol sensitivity. The main hypothesis to be tested in the proposed studies is that this residue and adjacent residues that are also involved in ion channel gating form a key site of alcohol action on the NMDA receptor-ion channel. These studies will incorporate whole-cell and single-channel patch-clamp electrophysiological recording to investigate the following specific aims: 1) the role of domains adjacent to NR2A(Met823) in the regulation of NMDA receptor ion channel gating and alcohol sensitivity; 2) whether these regions constitute a key site of alcohol action on the NMDA receptor; 3) the precise kinetic mechanism by which alcohol interacts with these sites to alter NMDA receptor ion channel gating; and 4) whether effects of NMDA receptor mutations on gating kinetics and alcohol modulation observed in a non-neuronal cell line are also observed in CNS neurons. The results of these studies will yield important information about the molecular mechanism of alcohol modulation of the NMDA receptor, new insights into the structure and function of the NMDA receptor-ion channel, and a better understanding of the ways in which alcohols and similar molecules interact with proteins in general. Because NMDA receptors have vital and widespread roles in cognition, motor function, and memory, and contribute importantly to both the subjective effects of alcohol as well as its CNS depressant effects, the information gained in these studies will represent an important step forward in the understanding of alcohol effects on the nervous system. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Research Project (R01)
Project #
5R01AA015203-04
Application #
7390724
Study Section
Neurotoxicology and Alcohol Study Section (NAL)
Program Officer
Cui, Changhai
Project Start
2005-04-01
Project End
2010-03-31
Budget Start
2008-04-01
Budget End
2009-03-31
Support Year
4
Fiscal Year
2008
Total Cost
$249,476
Indirect Cost
Name
Marquette University
Department
Other Basic Sciences
Type
Schools of Allied Health Profes
DUNS #
046929621
City
Milwaukee
State
WI
Country
United States
Zip Code
53201
Ren, Hong; Zhao, Yulin; Wu, Man et al. (2017) Two adjacent phenylalanines in the NMDA receptor GluN2A subunit M3 domain interactively regulate alcohol sensitivity and ion channel gating. Neuropharmacology 114:20-33
Zhao, Y; Ren, H; Peoples, R W (2016) Intersubunit interactions at putative sites of ethanol action in the M3 and M4 domains of the NMDA receptor GluN1 and GluN2B subunits. Br J Pharmacol 173:1950-65
Zhao, Yulin; Ren, Hong; Dwyer, Donard S et al. (2015) Different sites of alcohol action in the NMDA receptor GluN2A and GluN2B subunits. Neuropharmacology 97:240-50
Hu, Xiang-Qun (2015) Auto-inhibition at a ligand-gated ion channel: a cross-talk between orthosteric and allosteric sites. Br J Pharmacol 172:93-105
Ren, Hong; Zhao, Yulin; Wu, Man et al. (2013) A novel alcohol-sensitive position in the N-methyl-D-aspartate receptor GluN2A subunit M3 domain regulates agonist affinity and ion channel gating. Mol Pharmacol 84:501-10
Ren, Hong; Zhao, Yulin; Dwyer, Donard S et al. (2012) Interactions among positions in the third and fourth membrane-associated domains at the intersubunit interface of the N-methyl-D-aspartate receptor forming sites of alcohol action. J Biol Chem 287:27302-12
Ostrovskaya, Olga; Asatryan, Liana; Wyatt, Letisha et al. (2011) Ethanol is a fast channel inhibitor of P2X4 receptors. J Pharmacol Exp Ther 337:171-9
Salous, A K; Ren, H; Lamb, K A et al. (2009) Differential actions of ethanol and trichloroethanol at sites in the M3 and M4 domains of the NMDA receptor GluN2A (NR2A) subunit. Br J Pharmacol 158:1395-404
Ren, Hong; Salous, Abdelghaffar K; Paul, Jaclyn M et al. (2008) Functional interactions of alcohol-sensitive sites in the N-methyl-D-aspartate receptor M3 and M4 domains. J Biol Chem 283:8250-7
Hu, Xiang-Qun; Peoples, Robert W (2008) The 5-HT3B subunit confers spontaneous channel opening and altered ligand properties of the 5-HT3 receptor. J Biol Chem 283:6826-31

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