![]() |
|
|
PE Simson, HE Criswell, KB Johnson, RE Hicks and GR Breese
Department of Psychiatry, University of North Carolina at Chapel Hill, School of Medicine 27599.
Recent studies have demonstrated that ethanol blocks N-methyl-D- aspartate (NMDA) responses in vitro. In the present study, evidence is provided that ethanol, when administered by the systemic route to rats, also inhibits NMDA-evoked electrophysiological activity in vivo at behaviorally relevant doses. Ethanol, at doses in rats ranging from those producing minimal changes in spontaneous behavioral activity (0.75 g/kg) to those producing marked suppression of behavioral activity (2.5 g/kg), produced a dose-dependent inhibition of the ability of NMDA, when iontophoresed onto neurons of the medial septum (MS), to activate MS neurons. However, at all doses of ethanol tested, a proportion of MS neurons responded to ethanol with essentially complete inhibition of NMDA-evoked activity, whereas other MS neurons responded to ethanol with little or no inhibition of NMDA-evoked activity. By way of comparison, MK-801, a non-competitive NMDA antagonist, antagonized NMDA-evoked activity in all MS neurons tested. In contrast to the actions of ethanol, MK-801 increased, rather than decreased, behavioral activity even at doses that completely inhibited NMDA-evoked activity in all MS neurons tested. These latter findings provide evidence that inhibition of NMDA-evoked activity cannot account for all of the behavioral effects of ethanol. In conclusion, while the present results demonstrate for the first time that ethanol can inhibit NMDA-evoked neuronal activity in vivo, they also indicate that additional neural actions must contribute to ethanol's pharmacological profile.
This article has been cited by other articles:
![]() |
R. Pawlak, J. P. Melchor, T. Matys, A. E. Skrzypiec, and S. Strickland From The Cover: Ethanol-withdrawal seizures are controlled by tissue plasminogen activator via modulation of NR2B-containing NMDA receptors PNAS, January 11, 2005; 102(2): 443 - 448. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. A. Dissen, R. K. Dearth, H. M. Scott, S. R. Ojeda, and W. L. Dees Alcohol Alters Luteinizing Hormone Secretion in Immature Female Rhesus Monkeys by a Hypothalamic Action Endocrinology, October 1, 2004; 145(10): 4558 - 4564. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Ron Signaling Cascades Regulating NMDA Receptor Sensitivity to Ethanol Neuroscientist, August 1, 2004; 10(4): 325 - 336. [Abstract] [PDF] |
||||
![]() |
H. Ren, Y. Honse, and R. W. Peoples A Site of Alcohol Action in the Fourth Membrane-associated Domain of the N-Methyl-D-aspartate Receptor J. Biol. Chem., December 5, 2003; 278(49): 48815 - 48820. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. A. Masters and J. S. Stevenson A Theoretical Model of the Role of Brain Stem Nuclei in Alcohol-Mediated Arrhythmogenesis in Older Adults Biol Res Nurs, January 1, 2003; 4(3): 218 - 231. [Abstract] [PDF] |
||||
![]() |
H. E. Criswell, Z. Ming, B. L. Griffith, and G. R. Breese Comparison of Effect of Ethanol on N-Methyl-D-aspartate- and GABA-Gated Currents from Acutely Dissociated Neurons: Absence of Regional Differences in Sensitivity to Ethanol J. Pharmacol. Exp. Ther., January 1, 2003; 304(1): 192 - 199. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. C. Steffensen, Z. Nie, J. R. Criado, and G. R. Siggins Ethanol Inhibition of N-Methyl-D-aspartate Responses Involves Presynaptic gamma -Aminobutyric AcidB Receptors J. Pharmacol. Exp. Ther., August 1, 2000; 294(2): 637 - 647. [Abstract] [Full Text] |
||||
![]() |
R. L. Popp, R. L. Lickteig, and D. M. Lovinger Factors That Enhance Ethanol Inhibition of N-Methyl-D-Aspartate Receptors in Cerebellar Granule Cells J. Pharmacol. Exp. Ther., June 1, 1999; 289(3): 1564 - 1574. [Abstract] [Full Text] |
||||
![]() |
J. H. Krystal, I. L. Petrakis, E. Webb, N. L. Cooney, L. P. Karper, S. Namanworth, P. Stetson, L. A. Trevisan, and D. S. Charney Dose-Related Ethanol-like Effects of the NMDA Antagonist, Ketamine, in Recently Detoxified Alcoholics Arch Gen Psychiatry, April 1, 1998; 55(4): 354 - 360. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. M. Ronald, T. Mirshahi, and J. J. Woodward Ethanol Inhibition of N-Methyl-D-aspartate Receptors Is Reduced by Site-directed Mutagenesis of a Transmembrane Domain Phenylalanine Residue J. Biol. Chem., November 21, 2001; 276(48): 44729 - 44735. [Abstract] [Full Text] [PDF] |
||||