[Frontiers in Bioscience E4, 1358-1367, January 1, 2012]

Ethanol and adult CNS neurodamage: oxidative stress, but possibly not excitotoxicity

Michael A. Collins1, Edward J. Neafsey1

1Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago, Stritch School of Medicine, Maywood IL 60153

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Brain oxidative stress due to chronic ethanol
3.1. Essentials of brain oxidative stress related to ethanol
3.2. Chronic ethanol and brain oxidative stress in vivo
3.3. Oxidative stress relationships to withdrawal and neurodegeneration
4. Evaluations of excitotoxicity in ethanol-induced neurodamage
4.1. Neurodegeneration due to binge ethanol: the model(s) and evidence against excitotoxicity
4.2. Possible excitotoxicity in other chronic ethanol models
5. Oxidative stress and neurodegeneration in ethanol binge intoxication: nonexcitotoxic neuroinflammation
6. Perspective
7. Acknowledgements
8. References

1. ABSTRACT

Evidence from experiments with adult rodents chronically treated with ethanol via either repetitive binges or continuous intake/exposure supports the occurrence of brain oxidative stress and, at least in binge intoxication/rat models, its essential causative role in neurodamage. However, pharmacological antagonism experiments reveal that N-methyl-D-aspartate (NMDA) receptor-dependent excitotoxicity is not responsible for adult mammalian brain neurodegeneration caused by repetitive binge ethanol intoxication and withdrawals. Since NMDA receptor antagonists apparently are untested with respect to neuronal death/loss in continuous intake/ingestion rodent models, e.g., ethanol/water or ethanol/liquid diets, it is therefore erroneous to assert, as is often done, that excitotoxicity is an important mechanism for ethanol-induced adult mammalian brain damage. Alternatively, results from several laboratories indicate that neurodegeneration due to chronic binge ethanol exposure/withdrawal may be dependent on redox transcription factor signaling and neuroinflammatory/oxidative stress pathways (increased arachidonic acid mobilization and pro-inflammatory cytokines; decreased anti-inflammatory cytokines) downstream of microglial/astroglial activation and moderate yet significant brain edema.