The major goals of this project are to elucidate the molecular sites and mechanisms of action of ethanol on the N-methyI-D-aspartate class of ion channels. NMDA receptors are a subtype of glutamate-activated ligand-gated ion channel and they are involved in excitatory synaptic transmission in the brain. They mediate several forms of synaptic plasticity that underlie learning and memory and inhibition of their function by pharmacological or genetic means disrupts these complex behaviors. Acutely, ethanol inhibits ion flux through NMDA receptors while chronic exposure of neurons to ethanol induces an up-regulation in the functional status of these receptors that is manifested by signs of CNS excitability during withdrawal. Identifying the factors that regulate the inhibition of NMDA receptors by ethanol is important as acute sensitivity to the intoxicating effects of ethanol appears to be an important predictor of future alcohol abuse. Previous work carried out during this project identified several factors that can regulate the magnitude of inhibition of NMDA receptors to ethanol. These included subunit composition and post-translational modifications including phosphorylation and cytoskeleton interactions. In addition, this project identified an amino acid in the NR1 subunit of the receptor (F639) that when mutated to alanine significantly reduced the inhibitory effects of ethanol on NMDA receptors containing any NR2 subunit. In this application, three specific hypotheses are proposed to further define the molecular mechanisms that regulate the ethanol sensitivity of NMDA receptors.
Aim 1 will extend our mutagenesis studies to examine additional mutations at F639 and homologous NR2 sites as well as residues in other TM domains.
Aim 2 will investigate the effects of C-terminal phosphorylation of NR1 and NR2 residues on ethanol inhibition of NMDA receptors.
Aim 3 will express ethanol-insensitive receptors identified in Aims 1 and 2 in neurons in vitro and in vivo to address which effects of ethanol are mediated by inhibition of NMDA receptors.

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Research Project (R01)
Project #
2R01AA009986-10
Application #
6774634
Study Section
Neurotoxicology and Alcohol Study Section (NAL)
Program Officer
Sorensen, Roger
Project Start
1995-08-01
Project End
2009-03-31
Budget Start
2004-06-01
Budget End
2005-03-31
Support Year
10
Fiscal Year
2004
Total Cost
$200,750
Indirect Cost
Name
Medical University of South Carolina
Department
Neurosciences
Type
Schools of Medicine
DUNS #
183710748
City
Charleston
State
SC
Country
United States
Zip Code
29425
Nimitvilai, Sudarat; Uys, Joachim D; Woodward, John J et al. (2017) Orbitofrontal Neuroadaptations and Cross-Species Synaptic Biomarkers in Heavy-Drinking Macaques. J Neurosci 37:3646-3660
Cannady, Reginald; McGonigal, Justin T; Newsom, Ryan J et al. (2017) Prefrontal Cortex KCa2 Channels Regulate mGlu5-Dependent Plasticity and Extinction of Alcohol-Seeking Behavior. J Neurosci 37:4359-4369
Smothers, C Thetford; Woodward, John J (2016) Differential effects of TM4 tryptophan mutations on inhibition of N-methyl-d-aspartate receptors by ethanol and toluene. Alcohol 56:15-19
Padula, Audrey E; Griffin 3rd, William C; Lopez, Marcelo F et al. (2015) KCNN Genes that Encode Small-Conductance Ca2+-Activated K+ Channels Influence Alcohol and Drug Addiction. Neuropsychopharmacology 40:1928-39
McGuier, Natalie S; Padula, Audrey E; Lopez, Marcelo F et al. (2015) Withdrawal from chronic intermittent alcohol exposure increases dendritic spine density in the lateral orbitofrontal cortex of mice. Alcohol 49:21-7
Mulholland, Patrick J; Carpenter-Hyland, Ezekiel P; Woodward, John J et al. (2009) Ethanol disrupts NMDA receptor and astroglial EAAT2 modulation of Kv2.1 potassium channels in hippocampus. Alcohol 43:45-50
Sas, Andrew R; Bimonte-Nelson, Heather; Smothers, C Thetford et al. (2009) Interferon-alpha causes neuronal dysfunction in encephalitis. J Neurosci 29:3948-55
Smothers, C Thetford; Woodward, John J (2009) Expression of glycine-activated diheteromeric NR1/NR3 receptors in human embryonic kidney 293 cells Is NR1 splice variant-dependent. J Pharmacol Exp Ther 331:975-84
Xu, Minfu; Chandler, L Judson; Woodward, John J (2008) Ethanol inhibition of recombinant NMDA receptors is not altered by coexpression of CaMKII-alpha or CaMKII-beta. Alcohol 42:425-32
Mulholland, Patrick J; Carpenter-Hyland, Ezekiel P; Hearing, Matthew C et al. (2008) Glutamate transporters regulate extrasynaptic NMDA receptor modulation of Kv2.1 potassium channels. J Neurosci 28:8801-9

Showing the most recent 10 out of 38 publications