Toxic Effects Of Ethanol Research Articles

Protective effects of nicotine on ethanol-induced toxicity in cultured cerebellar granule cells.

Alcoholism is associated with a higher incidence of smoking. In addition to the stimulatory effects of both ethanol and nicotine on the mesolimbic reward pathway, nicotine's ability to counteract some of the adverse effects of ethanol (e.g. ataxia) may be a powerful incentive for alcohol consumers to increase their tobacco (nicotine) intake. The cerebellum is believed to play an important role in ethanol-induced ataxia. In this study, we sought to test the hypothesis that nicotine would protect against toxic effects of ethanol in primary cultures of cerebellar granule cells. Moreover, it was postulated that the effects of nicotine would be mediated through nicotinic receptors. Primary cultures of cerebellar granule cells were prepared from 20-day embryos obtained from timed-pregnant Sprague Dawley rats. Cells were cultured for 10 days and were then exposed for 3 days to various concentrations of ethanol with and without pretreatment with nicotine and nicotinic antagonists. Cellular toxicity was evaluated by measuring the lactate dehydrogenase level. Administration of ethanol (10-100 mM) resulted in a dose-dependent toxicity. Pretreatment with nicotine 1-20 micro M resulted in a dose-dependent protection against ethanol-induced toxicity. The effects of nicotine were blocked by pretreatment with nicotinic antagonists such as mecamylamine 1-20 micro M, dihydro-beta-erythroidine 1.0 nM-1.0 micro M and methyllycaconitine 5 nM-5 micro M in a dose-dependent manner. Thus, ethanol-induced cytotoxicity in primary cultures of cerebellar granule cells is blocked by pretreatment with nicotine. The effects of nicotine, in turn, may be blocked by nicotinic antagonists, implicating both high and low affinity nicotinic receptors in mediating the actions of nicotine. The exact mechanism of ethanol-induced toxicity and/or neuroprotection through activation of nicotinic receptors in this paradigm remains to be elucidated. The neuroprotective effect of nicotine against ethanol-induced toxicity in cerebellar neurons may be a contributing factor to the high incidence of smoking among alcoholics.

Drosophila melanogaster, A genetic model system for alcohol research

In its natural environment, which consists of fermenting plant materials, the fruit fly Drosophila melanogaster encounters high levels of ethanol. Flies are well equipped to deal with the toxic effects of ethanol; they use it as an energy source and for lipid biosynthesis. The primary ethanol-metabolizing pathway in flies involves the enzymes alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH); their role in adaptation to ethanol-rich environments has been studied extensively. The similarity between Drosophila and mammals is not restricted to the manner in which they metabolize ethanol; behaviors elicited by ethanol exposure are also remarkably similar in these organisms. Flies show signs of acute intoxication, which range from locomotor stimulation at low doses to complete sedation at higher doses, they develop tolerance upon intermittent ethanol exposure, and they appear to like ethanol, showing preference for ethanol-containing media. Molecular genetic analysis of ethanol-induced behaviors in Drosophila, while still in its early stages, has already revealed some surprising parallels with mammals. The availability of powerful tools for genetic manipulation in Drosophila, together with the high degree of conservation at the genomic level, make Drosophila a promising model organism to study the mechanism by which ethanol regulates behavior and the mechanisms underlying the organism's adaptation to long-term ethanol exposure.

Lactobacillic acid accumulation in the plasma membrane of Oenococcus oeni: a response to ethanol stress?

It is known that ethanol strongly interferes with the development and activity of lactic acid bacteria in wine. In this work, it was observed that membrane composition was dependent of ethanol concentration and cell physiological state. The protein electrophoretic profile was modified in the membranes of Oenococcus oeni cultured in presence of 8 and 10% ethanol. Concerning the membrane lipid composition, it was observed that O. oeni maintained a high level of phospholipid biosynthesis via the relative increased biosynthesis of phosphoethanolamine and sphingomyelin in presence of ethanol. On the other hand, ethanol induced an increase in the membrane lactobacillic acid percentage at the expense of cis-vaccenic acid. This increased synthesis of lactobacillic acid appears as the more significant change induced by ethanol in O. oeni membrane. The increase of lactobacillic acid in the membrane of O. oeni clearly appears as a factor that provides protection against the toxic effect of ethanol, balancing the increase of membrane fluidity normally attributed to ethanol. The results presented in this paper constitute evidence that lactobacillic acid may have a part in the survival and or adaptive mechanisms developed by O. oeni under culture adverse conditions, allowing these bacteria to maintain their activity in the presence of ethanol, namely performing malolactic fermentation in wine.

Gender differences in alcohol metabolism. Physiological responses to ethanol.

A gender difference in alcohol pharmacokinetics has been suggested to explain why women are more vulnerable to ethanol's toxic effects. The results of animal experiments suggest that females exhibit higher alcohol metabolic rates than males as a result of hormonal differences. Experimental results examining gender differences in human alcohol metabolism have been inconsistent; the diversity of experimental protocols and variety of pharmacokinetic parameters reported have made comparisons of these studies very difficult. Variability in alcohol metabolic rate between individuals of the same sex is often significant, preventing an assessment of gender differences in some studies. This chapter attempts to summarize the findings of studies from the last decade that examined the role of gender and sex hormone differences on ethanol metabolism in men and women. The role of body composition, genetic factors, gastric and hepatic alcohol dehydrogenase, and gastric absorption in creating gender differences in alcohol metabolism is discussed. Suggestions are offered that may result in better cross-study comparisons and more consistent experimental results.

Gender And Peripheral Neuropathy In Chronic Alcoholism: A Clinical‐Electroneurographic Study

In some alcohol‐related pathologies of chronic alcoholism women are more vulnerable than men. A consecutive sample of 62 chronic alcoholics was studied, 18 females and 44 males, aged between 28 and 69 years to assess the incidence and distribution of peripheral neuropathy with regard to gender. All patients underwent clinical and neurological observations, laboratory tests, and electroneurography. Total lifetime dose of ethanol (TLDE) and other risk factors for neuropathy (disease duration, age, nutritional status) were calculated and correlated to sural nerve sensory‐evoked potential (SEP) amplitude. In 42 patients (67.7%), we observed the presence of clinical and/or infraclinical neuropathy, mostly axonal, in 29 males (65.9%) and 13 females (72.2%). In women, compared to men, TLDE and disease duration were significantly inversely correlated to sural nerve SEP amplitude, i.e in women, SEP amplitude is significantly reduced in relation to TLDE and disease duration increase. These data indicate a higher sensitivity of females towards the toxic effects of ethanol, other than malnutrition, on peripheral nerve fibres.

GENDER AND PERIPHERAL NEUROPATHY IN CHRONIC ALCOHOLISM: A CLINICAL-ELECTRONEUROGRAPHIC STUDY

In some alcohol-related pathologies of chronic alcoholism women are more vulnerable than men. A consecutive sample of 62 chronic alcoholics was studied, 18 females and 44 males, aged between 28 and 69 years to assess the incidence and distribution of peripheral neuropathy with regard to gender. All patients underwent clinical and neurological observations, laboratory tests, and electroneurography. Total lifetime dose of ethanol (TLDE) and other risk factors for neuropathy (disease duration, age, nutritional status) were calculated and correlated to sural nerve sensory-evoked potential (SEP) amplitude. In 42 patients (67.7%), we observed the presence of clinical and/or infraclinical neuropathy, mostly axonal, in 29 males (65.9%) and 13 females (72.2%). In women, compared to men, TLDE and disease duration were significantly inversely correlated to sural nerve SEP amplitude, i.e. in women, SEP amplitude is significantly reduced in relation to TLDE and disease duration increase. These data indicate a higher sensitivity of females towards the toxic effects of ethanol, other than malnutrition, on peripheral nerve fibres.

Influence of magnesium ions on heat shock and ethanol stress responses of Saccharomyces cerevisiae.

This study has highlighted the role of magnesium ions in the amelioration of the detrimental effects of ethanol toxicity and temperature shock in a winemaking strain of Saccharomyces cerevisiae. Specifically, results based on measurements of cellular viability and heat shock protein synthesis together with scanning electron microscopy have shown that, by increasing the bioavailability of magnesium ions, physiological protection is conferred on yeast cells. Elevating magnesium levels in the growth medium from 2 to 20 mM results in repression of certain heat shock proteins following a typical heat shock regime (30-42 degrees C shift). Seed inocula cultures prepropagated in elevated levels of magnesium (i.e. 'preconditioned') also conferred thermotolerance on cells and repressed the biosynthesis of heat shock proteins. Similar results were observed in response to ethanol stress. Extra- and intracellular magnesium may both act in the physiological stress protection of yeast cells and this approach offers potential benefits in alcoholic fermentation processes. The working hypothesis based on our findings is that magnesium protects yeast cells by preventing increases in cell membrane permeability elicited by ethanol and temperature-induced stress.

The influence of the nitric oxide synthase inhibitor L-NOARG on the effects of ethanol in rats after acute ethanol administration.

The aim of this work was to study the effects of the nitric oxide synthase inhibitor N(G)-nitro-L-arginine (L-NOARG) on the sedative and toxic effects of ethanol in rats. Ethanol at a dose of 3 g/kg, intraperitoneally induced sleep in rats (sleep time: 111.2+/-10.3 min.). Administration of the nitric oxide synthase inhibitor L-NOARG (20 and 40 mg/kg, intraperitoneally) 30 min. before ethanol significantly increased the duration of ethanol-induced sleep. L-NOARG at doses of 20 and 40 mg/kg reduced the exploratory activity of rats in the open-field test and significantly enhanced the sedative effect of ethanol in this test. It is possible that this effect is not caused by the interaction of ethanol with nitric oxide pathways but by synergistic CNS depression caused by ethanol and L-NOARG. L-NOARG (20 and 40 mg/kg) had no effect on ethanol concentrations in blood after acute ethanol administration (2 and 3 g/kg). Moreover, the combined administration of ethanol (2 g/kg) and L-NOARG (20 and 40 mg/kg) caused a decrease in the body weight of animals, observed for 14 days. Also, livers of these rats were studied for necrosis and connective tissue reaction. In histological studies L-NOARG at a dose of 40 mg/kg had no effect on hepatic necrosis caused by the acute administration of ethanol but strengthened connective tissue reaction. L-NOARG is widely used in pharmacological studies, including those concerning the effects of ethanol. However, on the basis of our data the possibility of toxic interactions with ethanol should be considered.

Early intracellular signalling pathway of ethanol in vascular smooth muscle cells

1. ERKs belong to MAP kinase family and are activated by several growth and stress factors. Although ethanol has been shown to modulate ERK1 and ERK2 (p44(mapk) and p42(mapk)) activity, it can also act as an antiproliferative agent in various mammalian cells. Since the nature of the antiproliferative effect of ethanol in VSMCs has not been defined, we examined its effects on growth and on early intracellular events normally induced by growth factors in VSMCs. 2. Measurement of cytosolic Ca(2+) and pH in cell monolayers was performed using fura-2/AM and BCECF/AM, respectively. The effect of ethanol on VSMCs growth was assessed by [(3)H]-thymidine incorporation, by cell counting and by determination of the caspase 3 activity. Stimulation of ERK1 and ERK2 was examined by the chemiluminescence Western blotting method. The expression of c-fos was quantitated by Northern blotting. Determination of inositolphosphates was performed after labelling of VSMCs with myo-[2-(3)H]-inositol and separation of inositolphosphates by HPLC. 3. Ethanol (0.3 - 1.0% v v(-1), 17 - 170 mM) induced a dose-dependent maximal stimulation of p44(mapk)/p42(mapk) at 30 min and expression of c-fos mRNA with a maximum at 120 min. Intracellular events upstream to MAP kinase, like an increase in [Ca(2+)](i), activation of the Na(+)/H(+) exchanger and formation of phosphoinositol metabolites were also markedly activated by ethanol. Treatment of VSMCs with ethanol for 3 - 5 min induced an increase in DNA synthesis whereas treatment of the cells for more than 30 min was toxic. Caspase 3 activity was not modulated by ethanol treatment of VSMCs. 4. We may postulate that the activation of these mitogenic signals including the elevation of DNA synthesis reflects a cell effort to protect itself against the toxic effects of ethanol.

Interaction of 1-Hydroxyethyl Radical with Antioxidant Enzymes

There is considerable interest in the role of the 1-hydroxyethyl radical (HER) in the toxic effects of ethanol. The goal of this study was to evaluate the effects of HER on classical antioxidant enzymes. The interaction of acetaldehyde with hydroxylamine-o-sulfonic acid has been shown to produce 1,1′-dihydroxyazoethane (DHAE); this compound appears to be highly unstable, and its decomposition leads to the generation of HER. Addition of DHAE into a solution of PBN led to the appearance of the typical EPR spectra of PBN/HER adduct. No PBN/HER spin adduct was detected when DHAE was incubated with 0.1 M PBN in the presence of GSH. In the absence of PBN, DHAE oxidized ascorbic acid to semidehydroascorbyl radical, presumably via an ascorbate-dependent one-electron reduction of HER back to ethanol. Catalase was progressively inactivated by exposure to DHAE-generated HER in a time and HER concentration-dependent manner. Ascorbic acid and PBN gave full protection to catalase against HER-dependent inactivation. The antioxidants 2-tert-butyl-4-methylphenol, propylgallate, and α-tocopherol-protected catalase against inactivation by 84, 88, and 39%, respectively. Other antioxidant enzymes were also sensitive to exposure to HER. Glutathione reductase, glutathione peroxidase, and superoxide dismutase were inactivated by 46, 36, and 39%, respectively, by HER. The results reported here plus previous results showing HER interacts with GSH, ascorbate, and α-tocopherol suggest that prolonged generation of HER in cells from animals chronically exposed to ethanol may lower the antioxidant defense status, thereby contributing to mechanisms by which ethanol produces a state of oxidative stress and produces toxicity.

Alcohol as a Risk Factor for Brain Damage: Neurologic Aspects

Alcohol consumption in excess affects the brain negatively, both immediately and in the long‐term. Brain lesions in alcohol abusers are multiple and are multifactorial in origin. The toxic effect of ethanol, withdrawal from alcohol, nutritional deficits, and electrolyte disturbances, as well as liver damage, may contribute to the ethiopathogenesis of brain injury. The susceptibility of the brain to the negative effects of alcohol may be influenced by sex and age. The role of genetic factors and interactions of several licit and illicit drugs with alcohol needs further investigation.

Response to Dr. Addolorato et al.

Glória, Luísa1,*; Cravo, Marília1; Camilo, M E1; Resende, Manuela1; Cardoso, Neves J1; Oliveira, Gouveia A1; Leitão, Nobre C1; Mira, Costa F1 Author Information

Neuroanatomical and neurophysiological mechanisms involved in central nervous system dysfunctions induced by prenatal alcohol exposure.

One of the most severe consequences of maternal ethanol consumption is the damage to the developing central nervous system, which is manifested by long-term cognitive and behavioral deficits in the offspring. Prenatal exposure to ethanol affects many crucial neurochemical and cellular components of the developing brain. Ethanol interferes with all of the stages of brain development, and the severity of the damage depends on the amount of ethanol intake and level of exposure. Experimental observations also indicate that the toxic effects of ethanol are not uniform: some brain regions are more affected than others and, even within a given region, some cell populations are more vulnerable than others. The neocortex, the hippocampus, and the cerebellum are the regions in which the neurotoxic effects of ethanol have been associated with the behavioral deficits. At the cellular level, ethanol disrupts basic developmental processes, including interference with division and proliferation, cell growth, and differentiation and the migration of maturing cells. Alterations in astroglia development and in neuronal-glial interactions may also influence the development of the nervous system. An impairment of several neurotransmitter systems and/or their receptors, as well as changes in the endocrine environment during brain development, are also important factors involved in the behavioral dysfunctions observed after prenatal ethanol exposure. Finally, some molecular mechanisms of ethanol-induced behavioral dysfunctions will be discussed.

Alcohol as a risk factor for brain damage: neurologic aspects.

Alcohol consumption in excess affects the brain negatively, both immediately and in the long-term. Brain lesions in alcohol abusers are multiple and are multifactorial in origin. The toxic effect of ethanol, withdrawal from alcohol, nutritional deficits, and electrolyte disturbances, as well as liver damage, may contribute to the ethiopathogenesis of brain injury. The susceptibility of the brain to the negative effects of alcohol may be influenced by sex and age. The role of genetic factors and interactions of several licit and illicit drugs with alcohol needs further investigation.

DNA Damage, DNA Repair, and Alcohol Toxicity—A Review

Alcohol (ethanol) is clearly a toxic substance when consumed in excess. Chronic alcohol abuse results in a variety of pathological effects, including damage to the liver and brain, as well as other organs, and is associated with an increased risk of certain types of cancers. Alcohol consumption by pregnant women can result in fetal alcohol effects and fetal alcohol syndrome. All of these toxic effects are well documented. What is needed at present is a complete understanding of the molecular mechanisms by which alcohol causes these toxic effects. Such an understanding may lead to better treatments of some of these toxic effects. This review, focuses on the possibility that toxic effects of ethanol are mediated, at least in part, by damage to DNA. In particular, I emphasize data on the production of endogenous DNA-damaging molecules as a result of alcohol consumption and metabolism. Specific examples of DNA-damaging molecules to be considered are reactive oxygen species, including oxygen radicals, lipid peroxidation products, and acetaldehyde. The relevant DNA repair pathways that protect cells against DNA damage produced by these molecules will also be reviewed. The goal of this review is to integrate recent results from the fields of mutagenesis and DNA repair with the alcohol toxicity literature, with the aim of stimulating research into the role of DNA damage in different types of alcohol toxicity and the role of DNA repair in protecting cells from alcohol-related damage.

Silibinin, a plant extract with antioxidant and membrane stabilizing properties, protects exocrine pancreas from cyclosporin A toxicity.

Silymarin can be extracted from the milk thistle, and silibinin is the main component of the plant extract. Possibly due to their antioxidant and membrane-stabilizing properties, the compounds have been shown to protect different organs and cells against a number of insults. Thus liver, kidney, erythrocytes and platelets have been protected from the toxic effects of ethanol, carbon tetrachloride, cold ischemia and drugs, respectively. The effect of silibinin on endocrine and exocrine pancreas, however, has not been studied. We therefore investigated whether silibinin treatment attenuates cyclosporin A (CiA) toxicity on rat endocrine and exocrine pancreas. Groups of 15 male Wistar rats were treated for 8 days with CiA and/or silibinin. On day 9, endocrine and exocrine pancreatic functions were tested in vitro. At the end of the treatment period, blood glucose levels in vivo were significantly higher in rats treated with CiA while silibinin did not affect glucose levels. In vitro, insulin secretion was inhibited after treatment with silibinin, but amylase secretion was not affected. After treatment with CiA both insulin and amylase secretion were reduced. Silibinin and CiA had an additive inhibitory effect on insulin secretion, but silibinin attenuated CiA-induced inhibition of amylase secretion. Despite CiA treatment, amylase secretion was in fact restored to normal with the highest dose of silibinin. Thus silibinin inhibits glucose-stimulated insulin release in vitro, while not affecting blood glucose concentration in vivo. This combination of effects could be useful in the treatment of non-insulin-dependent diabetes mellitus. Furthermore, silibinin protects the exocrine pancreas from CiA toxicity. As this inhibitory effect is probably unspecific, silibinin may also protect the exocrine pancreas against other insult principles, such as alcohol.

Ethanol-induced oxygen radical formation and lipid peroxidation in rat brain: effect of chronic alcohol consumption.

The effect of chronic and in vitro ethanol exposure on brain oxygen radical formation and lipid peroxidation was analyzed. Ethanol induces a dose-dependent increase in lipid peroxidation in brain homogenates. The peroxidative effects of alcohol seem to be related to both cytochrome P450 and the ethanol-inducible form of cytochrome P450 (CYP2E1), because preincubation with metyrapone (an inhibitor of cytochrome P450) or with an antibody against CYP2E1 abolished the ethanol-increased lipid peroxidation. Using the formation of dichlorofluorescein, we also demonstrated that both in vitro and chronic alcohol exposure significantly enhanced the formation of oxygen radical species in synaptosomes. Chronic alcohol treatment also leads to an induction of cytochrome P450 (230%), NADPH cytochrome c reductase (180%), NADPH oxidation (184%), and CYP2E1 in brain microsomes. In addition, this treatment produced a decrease in the GSH/GSSG ratio in brain and significantly enhanced the levels of superoxide dismutase and catalase activities. This mechanism could be involved in the toxic effects of ethanol on brain and membrane alterations occurring after chronic ethanol intake.

Chronic alcoholic myopathy and nutritional status

To investigate the prevalence of alcoholic myopathy and its relationship to the nutritional status, we performed a muscle biopsy on the vastum lateralis of 60 consecutive hospitalized alcoholic patients using a Tru-Cut needle, processing it for light microscope and ultrastructural analysis. The nutritional status was assessed by anthropometric measurements such as midarm circumference, triceps skinfold and midarm muscle area, and serum albumin. The hallmark of chronic alcoholic myopathy, fiber muscle atrophy, was present in 33% of the patients, necrosis scarcely being observed (1.5%). Ultrastructural alterations as lipid and glycogen accumulation or mitochondrial and myofibrillar alterations were nonspecific and observed in nearly all the cases where atrophy was present. Malnutrition was frequent in our patients: 39% and 34% showed a triceps skinfold and a midarm muscle area, respectively, under the fifth populational percentile. Patients with muscle fiber atrophy or ultrastructural changes showed a worse nutritional status, not only regarding muscle protein (assessed by midarm muscle area or creatininuria and explained by fiber atrophy), but also regarding fat stores assessed by triceps skinfold. Toxic effect of ethanol and malnutrition may act synergistically leading to chronic alcoholic myopathy.

Hexokinases and catabolite repression in Candida utilis.

Like Saccharomyces cerevisiae, Candida utilis IGC 3092 has two hexokinases. Their kinetic behavior suggests that they are slightly different from those of S. cerevisiae, and although they are insensitive to xylose, they are affected by trehalose 6-P and ADP. Unlike some other yeast species, C. utilis hexokinases do not show a higher activity under repressing conditions but exhibit a constant fructose/glucose phosphorylation ratio (F/G) in any conditions used. It seems that hexokinase activities are not regulated in parallel with eatabolite repression in this strain [1]. A spontaneous mutant (SDM-1), deregulated for ~-glucosidase and with the glucose proton symport and invertase partially derepressed, was tested for its hexokinase regulation and compared with the wild-type (WT) strain. Studies done in crude extracts under optimum conditions (pH 8 and 30 ~ showed no difference between the two strains in the overall activity and F/G ratio [2]. However, a more detailed work under physiological conditions (pH 7 and 28 ~ showed the F/G ratio in the wild-type strain to be similar as under optimum assay conditions while the F/G ratio found in SDM-1 changed slightly to < 1; this happens at a higher degree also in derepressed S. cerevisiae [3]. As expected, kinetic experiments with glucose and fructose showed a sole apparent Km at high ATP concentration in wild-type crude extracts whereas biphasic kinetics was obtained in the mutant strain. Statistical analysis did not provide conclusive results on the existence of at least two systems with different affinities in the mutant. Responses to xylose and trehalose 6-P were the same for both WT and mutant hexokinases. However, the inhibition by ADP in the mutant was lower than in the WT. All these results suggest that the mutant has altered hexokinases. It is not clear if the alteration is the cause of the derepression or if it represents another failure in the pleiotropic derepressed mutant. The derepression did not translate into significant changes of the main kinetic parameters of batch culture growth on different substrates and different disolved oxygen concentrations. SDM-1 cultures growing on a maltose-glucose mixture consumed these sugars simultaneously, while the ethanol level in the medium remains low. In contrast, the WT shows a sequential sugar consumption, with ethanol production directly associated with glucose consumption. After its exhaustion, ethanol is rapidly uptaken up and a secondary, lower ethanol release is measured in the maltose phase. Maltose is not consumed by the WT until the ethanol concentration in the medium drops. This is predicted by the current explanation of the Kluyver effect, which relates the lack of maltose consumption to the toxic effect of ethanol [4]. The ability to ferment maltose was reported as negligible in other Candida utilis strains; however, the level of ethanol usually stays below 1 mmol/L, a concentration considered nonfermentative [4].

Ethanol and glucose-deprivation neurotoxicity in cortical cell cultures

The toxic effects of ethanol on rat cortical cell cultures were compared with neuronal damage induced by glucose deprivation. Exposure to decreased glucose concentrations produced dose-dependent neuronal injury, as indicated by the release of lactate dehydrogenase (LDH) into the culture medium. Complete glucose deprivation resulted in mean LDH release that was more than 60% greater than that from sister cultures incubated in the presence of 5.5 mmol/L glucose. Exposure to ethanol (25, 50, or 100 mmol/L) similarly resulted in dose-related LDH release. The degree of injury resulting from complete glucose deprivation or 100 mmol/L ethanol approximated that produced by exposure to 100 mmol/L glutamic acid. Ethanol did not significantly alter LDH release from cultures consisting of only astrocytes. Both effects were inhibited by the N-methyl- d-aspartate (NMDA) receptor antagonist, d,l-2-amino-5-phosphonovaleric acid (APV). Glutamate levels were increased in the culture medium to 191% ± 8% of the control value after glucose deprivation ( P < .001) and to 186% ± 16% after exposure to 100 mmol/L ethanol ( P < .01). 3H-glutamate uptake by cultured astrocytes was reduced by glucose deprivation and by ethanol. This range of ethanol concentrations has previously been shown to inhibit hexose uptake by cultured astrocytes. The present results suggest that decreased glucose uptake by astrocytes in the presence of ethanol impairs their uptake of glutamate, which contributes to excitotoxic neuronal injury.