| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Division of Pharmacology and Toxicology, The College of Pharmacy, University of Texas, Austin, Texas 78712–0125
Submitted 15 October 2003; accepted in final form 23 January 2004
To discriminate between pre- and postsynaptic effects of ethanol on N-methyl-D-aspartate receptor (NMDAR) signaling in hippocampus, we adapted the technique of Sr2+ substitution to the hippocampal blind slice patch-clamp preparation. Hippocampal slices were isolated from 12- to 20-day-old rats that were killed in accordance with University of Texas Institutional Animal Care and Use Committee guidelines. NMDAR miniature excitatory postsynaptic currents (mEPSCs) were evoked from CA1 pyramidal neurons in the presence of Sr2+ (4 mM), causing the synchronous EPSC observed in the presence of Ca2+ to be supplanted by asynchronous mEPSCs. Amplitudes typically ranged from 5 to 40 pA and responded to the NMDAR antagonist (DL)-APV (50 µM), with a statistically significant reduction in mean amplitude. Ethanol (25, 50, and 75 mM) exerted dose-dependent effects on mEPSC amplitude and frequency. Peak amplitude inhibition was observed at 75 mM ethanol. Notably, ethanol significantly decreased event frequency at 50 and 75 mM ethanol. Ethanol (75 mM) also significantly increased the paired-pulse ratio of NMDAR EPSCs. Cumulative comparisons of decay time constants derived from single-exponential fitting of mEPSCs revealed significantly accelerated current decay kinetics in the presence of 75 mM ethanol. Taken together, these reductions in miniature event frequency and amplitude, concurrent with an increased rate of decay, suggest that the acute effects of ethanol on NMDAR signaling at hippocampal synapses are multifocal in nature. This finding of pre- and postsynaptic effects of ethanol on NMDAR signal strength in a brain region central to cognition is wholly consistent with previous reports of ethanol inhibition of NMDAR–long-term potentiation in vitro and with the profound cognitive deficits associated with binge-level intoxication in vivo.
This article has been cited by other articles:
|
|
 |
|
  A. W. Hendricson, R. E. Maldve, A. G. Salinas, J. W. Theile, T. A. Zhang, L. M. Diaz, and R. A. Morrisett Aberrant Synaptic Activation of N-Methyl-D-aspartate Receptors Underlies Ethanol Withdrawal Hyperexcitability J. Pharmacol. Exp. Ther., April 1, 2007; 321(1): 60 - 72. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Koyama, M. S. Brodie, and S. B. Appel Ethanol Inhibition of M-Current and Ethanol-Induced Direct Excitation of Ventral Tegmental Area Dopamine Neurons J Neurophysiol, March 1, 2007; 97(3): 1977 - 1985. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. R. Proctor, L. Diao, R. K. Freund, M. D. Browning, and P. H. Wu Synaptic GABAergic and glutamatergic mechanisms underlying alcohol sensitivity in mouse hippocampal neurons J. Physiol., August 15, 2006; 575(1): 145 - 159. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Karst and M. Joels Corticosterone Slowly Enhances Miniature Excitatory Postsynaptic Current Amplitude in Mice CA1 Hippocampal Cells J Neurophysiol, November 1, 2005; 94(5): 3479 - 3486. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Mameli, P. A. Zamudio, M. Carta, and C. F. Valenzuela Developmentally Regulated Actions of Alcohol on Hippocampal Glutamatergic Transmission J. Neurosci., August 31, 2005; 25(35): 8027 - 8036. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
