Correlated changes in NMDA receptor phosphorylation, functional activity, and sedation by chronic ethanol consumption.
Alcohol abuse leads to tolerance, dependence, and memory impairments that involve excitatory glutamatergic NMDA synaptic transmission. The NMDA receptor (NMDAR) is known to undergo activity-dependent adaptive functional changes. Since we observed that acute ethanol inhibition of the NMDAR was regulated by protein tyrosine phosphorylation, we investigated the role of protein tyrosine kinases and phosphatases on the NMDAR functions by chronic ethanol treatment. We carried out whole-cell recording, western blotting, and behavioral righting reflex measurements to assess the impact of chronic ethanol treatment on NMDAR function. Our results indicated that these receptors became resistant to the acute ethanol inhibition following chronic ethanol consumption. This resistance occurred without an increase in the NMDAR subunit expression but was associated with decreases in the levels of phospho-Y-1472 NR2B, increases in the levels of STEP33, increases in phospho-p38 mitogen-activated protein kinase (pp38 MAPK), and acquisition of tolerance to the sedative effects of ethanol. These data suggested that altered protein tyrosine phosphorylation of the NMDAR subunits significantly contributes to functional changes of this receptor by chronic ethanol ingestion. Therefore, preservation of the integrity of tyrosine phosphorylation mechanisms of the NMDAR may be important in controlling the progression of alcohol tolerance and dependence.
Wu
Peter H
PH
VA Eastern Colorado Healthcare System, Denver, Colorado, USA. peter.wu@ucdenver.edu
Coultrap
Steven
S
Browning
Michael D
MD
Proctor
William R
WR
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D001596:Benzylamines / Q000494:pharmacology; D001640:Bicuculline / Q000031:analogs & derivatives / Q000494:pharmacology; D002492:Central Nervous System Depressants / Q000008:administration & dosage / Q000494:pharmacology*; D000431:Ethanol / Q000008:administration & dosage / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects* / Q000502:physiology; D005247:Feeding Behavior / Q000187:drug effects; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D006624:Hippocampus / Q000166:cytology; D066298:In Vitro Techniques; D008297:Male; D018408:Patch-Clamp Techniques / Q000379:methods; D010721:Phosphinic Acids / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D013223:Statistics as Topic; D013997:Time Factors; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D001596:Benzylamines; D002492:Central Nervous System Depressants; D018691:Excitatory Amino Acid Antagonists; D058787:GABA-A Receptor Antagonists; C121001:NR2B NMDA receptor; D010721:Phosphinic Acids; D016194:Receptors, N-Methyl-D-Aspartate; C083008:CGP 52432; D000431:Ethanol; C036615:bicuculline methobromide; D015763:2-Amino-5-phosphonovalerate; D048051:p38 Mitogen-Activated Protein Kinases; D001640:Bicuculline