Effects of chronic ethanol administration on free radical defence in rat myocardium

The Status of Oxidative Stress in Patients with Alcohol Dependence: A Meta-Analysis

Alcohol-induced oxidative stress (OS) plays a pivotal role in the pathophysiology of alcohol dependence (AD). This meta-analysis was aimed at investigating the changes in the levels of OS biomarkers in AD patients. We included relevant literature published before 1 April 2022, from the PubMed, Web of Science, and EBSCO databases following PRISMA guidelines. Finally, 15 eligible articles were enrolled in this meta-analysis, including 860 patients and 849 controls. Compared with healthy controls, AD patients had lower activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes, and lower levels of albumin, while levels of malondialdehyde (MDA), vitamin B12, homocysteine, and bilirubin were significantly increased in serum/plasma samples of AD subjects (all p < 0.05). In male patients, the activities of SOD and GPx were increased in serum/plasma but decreased in erythrocytes (all p < 0.05). The opposite trends in the level of SOD and GPx activities in serum/plasma and erythrocytes of male patients could be used as the biomarker of alcohol-induced OS injury, and the synergistic changes of MDA, vitamin B12, albumin, bilirubin, and homocysteine levels should also be considered.

Nebivolol Prevents Up-Regulation of Nox2/NADPH Oxidase and Lipoperoxidation in the Early Stages of Ethanol-Induced Cardiac Toxicity

Changes in redox state are described in the early stages of ethanol-induced cardiac toxicity. Here, we evaluated whether nebivolol would abrogate ethanol-induced redox imbalance in the heart. Male Wistar rats were treated with a solution of ethanol (20% v/v) for 3 weeks. Treatment with nebivolol (10 mg/kg/day; p.o. gavage) prevented the increase of both superoxide (O2•-) and thiobarbituric acid reactive substances (TBARS) in the left ventricle of rats chronically treated with ethanol. Neither ethanol nor nebivolol affected the expression of Nox4, p47phox, or Rac-1. Nebivolol prevented ethanol-induced increase of Nox2 expression in the left ventricle. Superoxide dismutase (SOD) activity as well as the concentration of reduced glutathione (GSH) was not altered by ethanol or nebivolol. Augmented catalase activity was detected in the left ventricle of both ethanol- and nebivolol-treated rats. Treatment with nebivolol, but not ethanol increased eNOS expression in the left ventricle. No changes in the activity of matrix metalloproteinase (MMP)2 or in the expressions of MMP2, MMP9, and tissue inhibitor metalloproteinase (TIMP)1 were detected after treatment with ethanol or nebivolol. However, ethanol increased the expression of TIMP2, and this response was prevented by nebivolol. Our results provided novel insights into the mechanisms underlying the early stages of the cardiac injury induced by ethanol consumption. We demonstrated that Nox2/NADPH oxidase-derived ROS play a role in ethanol-induced lipoperoxidation and that this response was prevented by nebivolol. In addition, we provided evidence that MMPs are not activated in the early stages of ethanol-induced cardiac toxicity.

Etiology of alcoholic cardiomyopathy: Mitochondria, oxidative stress and apoptosis

Putative mechanisms leading to the development of alcoholic cardiomyopathy (ACM) include the interrelated cellular processes of mitochondria metabolism, oxidative stress and apoptosis. As mitochondria fuel the constant energy demands of this continually contracting tissue, it is not surprising that alcohol-induced molecular changes in this organelle contribute to cardiac dysfunction and ACM. As the causal relationship of these processes with ACM has already been established, the primary objective of this review is to provide an update of the experimental findings to more completely understand the aforementioned mechanisms. Accordingly, recent data indicate that alcohol impairs mitochondria function assessed by membrane potential and respiratory chain activity. Indictors of oxidative stress including superoxide dismutase, glutathione metabolites and malondialdehyde are also adversely affected by alcohol oftentimes in a sex-dependent manner. Additionally, myocardial apoptosis is increased based on assessment of TUNEL staining and caspase activity. Recent work has also emerged linking alcohol-induced oxidative stress with apoptosis providing new insight on the codependence of these interrelated mechanisms in ACM. Attention is also given to methodological differences including the dose of alcohol, experimental model system and the use of males versus females to highlight inconsistencies and areas that would benefit from establishment of a consistent model.

Myocardial Oxidative Stress and Toxicity Induced by Acute Ethanol Exposure in Mice

Alcoholic cardiomyopathy has been known for a long time, but there is little mechanistic insight into this important clinical problem. The present study was undertaken using a mouse model to test the hypothesis that alcohol exposure induces cardiac injury through induction of oxidative stress. Adult female Friend Virius B-type (FVB) mice were treated with ethanol by gavage at a dose of 5 g/kg. Six hours after the treatment, ethanol-induced myocardial injury was observed, as indicated by a significant increase in serum creatine phosphokinase activity, a common biomarker of myocardial injury, and myocardial ultrastructural alterations, predominantly mitochondrial swelling and cristae disarray and reduction in numbers. The myocardial injury was associated with a significant increase in the myocardial lipid peroxidation, determined by measuring thiobarbituric acid reactive substances (TBARS), and a significant increase in protein oxidation as measured by a protein carbonyl content assay. Acute alcohol exposure decreased glutathione (GSH) content in the heart, more so in the mitochondria than in the cytosol. These alcohol-induced myocardial injuries and oxidative stresses were all significantly inhibited by supplementation with N-acetyl-L-cysteine (NAC) prior to alcohol exposure. However, NAC did not affect the rise in blood alcohol concentrations following alcohol exposure. This study thus demonstrates that acute alcohol administration causes myocardial injury through, at least in part, the induction of oxidative stress. A rapid decrease in mitochondrial GSH content may be partially responsible for the observed mitochondrial damage.

Oxidative damage and histopathological changes in lung of rat chronically exposed to nicotine alone or associated to ethanol

Smoking is the most important preventable risk factor of chronic obstructive pulmonary disease and lung cancer. This study was designed to investigate oxidative damage and histopathological changes in lung tissue of rats chronically exposed to nicotine alone or supplemented with ethanol. Twenty-four male Wistar rats divided into three groups were used for the study. The nicotine group received nicotine (2.5mg/kg/day); the nicotine-ethanol group was given simultaneously same dose of nicotine plus ethanol (0.2g/kg/day), while the control group was administered only normal saline (1 ml/kg/day). The treatment was administered by subcutaneous injection once daily for a period of 18 weeks. Chronic nicotine administration alone or combined to ethanol caused a significant increase in malondialdehyde (MDA) level, superoxide dismutase (SOD) activity and catalase (CAT) activity in lung tissue compared to control rats suggesting an oxidative damage. However, these increases were mostly prominent in nicotine group. The histopathological examination of lung tissue of rats in both treated groups revealed many alterations in the pulmonary structures such as emphysema change (disappearance of the alveolar septa, increased irregularity and size of air sacs) and marked lymphocytic infiltration in perivascular and interstitial areas. However, the changes characterized in the nicotine group (pulmonary congestion, hemorrhage into alveoli and interstitial areas, edema) were more drastic than those observed in the nicotine-ethanol group, and they can be attributed to a significant degree of capillary endothelial permeability and microvascular leak. Conversely, the ethanol supplementation caused an appearance of fatty change and fibrosis in pulmonary tissue essentially due to a metabolism of ethanol. Finally, the lung damage illustrated in nicotine group was more severe than that observed in the nicotine-ethanol group. We conclude that the combined administration of nicotine and ethanol may moderate the effect of nicotine administered independently by counteractive interactions between these two drugs.

In vitro dose and duration dependent approaches for the assessment of ameliorative effects of nanoconjugated vancomycin against Staphylococcus aureus infection induced oxidative stress in murine peritoneal macrophages

AIMS

The present study was aimed to evaluate the in vitro ameliorative effect of nanoconjugated vancomycin (NV) against vancomycin sensitive and resistant strains of Staphylococcus aureus infection-induced oxidative stress in murine peritoneal macrophage.

METHODS

Peritoneal macrophages from mice were treated with VSSA and VRSA (5 × 10(6) CFU/mL), VSSA + NV (5-250 μg/ml) and VRSA + NV (5-250 μg/ml) for 18 h, having 3 h interval in culture media; and the superoxide anion generation, lipid peroxidation, protein oxidation, antioxidant enzymes status and glutathione enzymes activity were monitored.

RESULTS

The significantly increased free radical generation, lipid peroxidation, protein carbonyls and oxidized glutathione levels were observed in VSSA and VRSA treated group as compared to control group; where as reduced glutathione level, antioxidant enzymes status and glutathione dependent enzymes were decreased significantly. All these changes come near to control in NV treated group in a dose and duration dependent fashion. Among the different doses and duration intervals of NV, maximum ameliorative effect was observed by 100 μg/ml for 12 h treatment which does not produce any damage to the cell.

CONCLUSIONS

These findings suggest the potential use and beneficial role of nanoconjugated vancomycin as a modulator of S. aureus infection-induced cellular damage in murine peritoneal macrophage.

Alcoholic cardiomyopathy: pathophysiologic insights

Alcoholic cardiomyopathy (ACM) is a specific heart muscle disease found in individuals with a history of long-term heavy alcohol consumption. ACM is associated with a number of adverse histological, cellular, and structural changes within the myocardium. Several mechanisms are implicated in mediating the adverse effects of ethanol, including the generation of oxidative stress, apoptotic cell death, impaired mitochondrial bioenergetics/stress, derangements in fatty acid metabolism and transport, and accelerated protein catabolism. In this review, we discuss the evidence for such mechanisms and present the potential importance of drinking patterns, genetic susceptibility, nutritional factors, race, and sex. The purpose of this review is to provide a mechanistic paradigm for future research in the area of ACM.

Antioxidant profile changes in reproductive tissues of rats treated with nicotine

OBJECTIVES:

Nicotine intake has been associated with reduced fertility, although the mechanisms responsible are still unclear. However, oxidative stress has been repeatedly implicated as the leading cause of male infertility. This study was therefore designed to investigate the effects of nicotine administration on testicular oxidant and antioxidant system in male albino rats.

MATERIALS AND METHODS:

Forty male rats weighing between 150 and 180 g were divided into five groups and treated orally for 30 days. Group I, which served as the control received 0.2 ml/kg normal saline, Groups II and III received 0.5 mg/kg and 1.0 mg/kg body weight (BW) of nicotine respectively. The fourth and fifth groups were administered with 0.5 mg/kg and 1.0 mg/kg BW of nicotine, but were left untreated for another 30 days. Homogenate of testis and epididymis were assayed for lipid peroxidation and anti-oxidant enzyme.

RESULTS:

The results show a significant decrease (P < 0.05) in testicular glutathione peroxidase, glutathione reductase, catalase and superoxide dismutase while a significant increase (P < 0.05) was observed in testicular lipid peroxidation and nitric oxide level in both groups when compared with the control.

CONCLUSION:

This experiment established that nicotine administration is associated with decreased testicular antioxidant and increase testicular lipid peroxidation, which might be a mechanism by which nicotine induce infertility.

Modulation of lipid peroxidation and antioxidant defense systems in rat intestine by subchronic fluoride and ethanol administration

Excessive consumption of fluoride and ethanol has been identified as injurious to human health. Fluoride and ethanol co-exposures are commonly seen among the alcoholics residing in endemic fluoride areas worldwide. This study was undertaken to examine the modulation of lipid peroxidation and antioxidant defense systems in rat intestine by subchronic fluoride and ethanol administration. Female Sprague-Dawley rats were divided into four groups: group I (control), group II (fluoride was given orally at a dose of 25 mg/kg body weight), group III (30% ethanol was given orally at a dose of 1 mL/kg body weight), and group IV (a combination of fluoride and ethanol was administered orally at the dose described for groups II and III). Lipid peroxidation was elevated (P<.05) in intestine of rats by fluoride or ethanol treatments for 20 or 40 days. However, glutathione content was reduced by fluoride (32 and 44%) and ethanol (21 and 40%) treatments after 20 and 40 days, respectively. Fluoride-exposed animals showed reduction (P<.05) in the activities of superoxide dismutase (22 and 42%), catalase (30 and 37%), glutathione peroxidase (22 and 35%), glutathione reductase (32 and 34%), and glutathione-S-transferase (24 and 30%) after 20 and 40 days. A similar decrease (P<.05) in the activities of these enzymes was also noticed in animals exposed to ethanol for 20 or 40 days. The observed changes in lipid peroxidation, reduced glutathione levels, and enzyme systems were further augmented in intestine of rats exposed to fluoride and ethanol together. Intestinal histology showed large reactive lymphoid follicles along with mild excess of lymphocytes in lamina propria of villi, villous edema, focal ileitis, and necrosis of villi in animals exposed to fluoride and ethanol for 40 days. These findings suggest that fluoride and ethanol exposure induces considerable changes in lipid peroxidation, antioxidant defense, and morphology of rat intestine, which may affect its functions.

Mitochondrial network determines intracellular ROS dynamics and sensitivity to oxidative stress through switching inter-mitochondrial messengers

Oxidative stresses caused by reactive oxygen species (ROS) can induce rapid depolarization of inner mitochondrial membrane potential and subsequent impairment of oxidative phosphorylation. Damaged mitochondria produce more ROS, especially the superoxide anion (O₂⁻) and hydrogen peroxide (H₂O₂), which potentiate mitochondria-driven ROS propagation, so-called ROS-induced ROS release (RIRR), via activation of an inter-mitochondria signaling network. Therefore, loss of function in only a fraction of mitochondria might eventually affect cell viability through this positive feedback loop. Since ROS are very short-lived molecules in the biological milieu, mitochondrial network dynamics, such as density, number, and spatial distribution, can affect mitochondria-driven ROS propagation. To address this issue, we developed a mathematical model using an agent-based modeling approach, and tested the effect of mitochondrial network dynamics on RIRR for mitochondria under various conditions. Simulation results show that the intracellular ROS signaling pattern, such as ROS propagation speed and oxidative stress vulnerability, are critically affected by mitochondrial network dynamics. Mitochondrial network dynamics of mitochondrial distribution, density, activity, and size can mediate inter-mitochondrial signaling under certain conditions and determine the identity of the ROS signaling pattern. We further elucidated the potential mechanism of these actions, i.e., conversion of major messenger molecules involved in ROS signaling. If the average distance between neighboring mitochondria is large or mitochondrial distribution becomes randomized, messenger molecule of the ROS signaling network can be switched from O₂⁻ to H₂O₂. In this case, mitochondria-driven ROS propagation is efficiently blocked by introduction of excess cytosolic glutathione peroxidase 1, while introduction of cytosolic superoxide dismutase has no effect. Together, these results suggest that mitochondrial network dynamics is a major determinant for cellular responses to RIRR through changing the key messenger molecules.

Nitric oxide mediated Staphylococcus aureus pathogenesis and protective role of nanoconjugated vancomycin

OBJECTIVE

To test the survival of Staphylococcus aureus (S. aureus) inside lymphocyte that contributes to the pathogenesis of infection and possible anti-inflammatory and antioxidative effect of nanoconjugated vancomycin against in vivo S. aureus infection in a dose and duration dependent manner.

METHODS

5×10(6) CFU/mL vancomycin-sensitive S. aureus (VSSA) and vancomycin-resistive S. aureus (VRSA) were challenged in Swiss male mice for 3 days, 5 days, 10 days and 15 days, respectively. Bacteremia and inflammatory parameters were observed to evaluate the duration for development of VSSA and VRSA infection. 100 mg/kg bw/day and 500 mg/kg bw/day nanoconjugated vancomycin were administrated to VSSA and VRSA infected group for 5 days. Bacteremia, inflammatory parameters and oxidative stress related parameters were tested to observe the effective dose of nanoconjugated vancomycin against VSSA and VRSA infection. Nanoconjugated vancomycin was treated at a dose of 100 mg/kg bw/day and 500 mg/kg bw/day, respectively, to VSSA and VRSA infected group for successive 5 days, 10 days and 15 days. Bacteremia, inflammatory parameters and oxidative stress related parameters were observed to assess the effective duration of nanoconjugated vancomycin against VSSA and VRSA infection.

RESULTS

The result revealed that in vivo VSSA and VRSA infection developed after 5 days of challenge by elevating the NO generation in lymphocyte and serum inflammatory markers. Administration with nanoconjugated vancomycin to VSSA and VRSA infected group at a dose of 100 mg/kg bw/day and 500 mg/kg bw/day, respectively, for successive 10 days eliminated bacterimia, decreased NO generation in lymphocyte, serum inflammatory markers and increased antioxidant enzyme status.

CONCLUSIONS

These findings suggest, in vivo challenge of VSSA and VRSA for 5 days can produce the highest degree of damage in lymphocyte which can be ameliorated by treatment with nanoconjugated vancomycin for 10 successive days.

Locomotor damage and brain oxidative stress induced by lead exposure are attenuated by gallic acid treatment

We investigated the antioxidant potential of gallic acid (GA), a natural compound found in vegetal sources, on the motor and oxidative damages induced by lead. Rats exposed to lead (50 mg/kg, i.p., once a day, 5 days) were treated with GA (13.5mg/kg, p.o.) or EDTA (110 mg/kg, i.p.) daily, for 3 days. Lead exposure decreased the locomotor and exploratory activities, reduced blood ALA-D activity, and increased brain catalase (CAT) activity without altering other antioxidant defenses. Brain oxidative stress (OS) estimated by lipid peroxidation (TBARS) and protein carbonyl were increased by lead. GA reversed the motor behavior parameters, the ALA-D activity, as well as the markers of OS changed by lead exposure. CAT activity remained high, possibly as a compensatory mechanism to eliminate hydroperoxides during lead poisoning. EDTA, a conventional chelating agent, was not beneficial on the lead-induced motor behavior and oxidative damages. Both GA (less) and EDTA (more) reduced the lead accumulation in brain tissue. Negative correlations were observed between the behavioral parameters and lipid peroxidation and the lead levels in brain tissue. In conclusion, GA may be an adjuvant in lead exposure, mainly by its antioxidant properties against the motor and oxidative damages resulting from such poisoning.

Supplementation of ascorbic acid prevents oxidative damages in arsenic-loaded hepatic tissue of rat: An ex vivo study

Oxidative stress due to arsenic toxicity and ameliorative potentiality of L-ascorbic acid was evaluated in an ex vivo system of rat hepatic tissue. The study revealed that arsenic increased the activity of superoxide dismutase (SOD) and catalase (CAT) and the level of lipid peroxidation (LPO), protein carbonyl (PC) and nitric oxide (NO) at 1 hour, 1.5 hours and 2 hours of incubation. Co-treatment with L-ascorbic acid was found effective to normalize the activity of SOD and CAT and the production of LPO, PC and NO in hepatic tissue. This ex vivo study suggested that ascorbic acid is helpful to ameliorate arsenic-induced oxidative stress. This may be one of the alternative screening systems to study the efficacy of antioxidant and hepatoprotective agent.

Effects of Some Antibiotics on Activity of Glucose-6-Phosphate Dehydrogenase from Human Erythrocytes In Vitro and Effect of Isepamicin Sulfate on Activities of Antioxidant Enzymes in Rat Erythrocytes

The purpose of this study was to investigate effects of some antibiotics on glucose-6-phosphate dehydrogenase (G6PD), antioxidant enzymes, and malondialdehyde (MDA). Initially, for in vitro studies, G6PD was purified from human erythrocyte, 9811-fold in a yield of 42.4% by using ammonium sulfate precipitation and 2',5' ADP-Sepharose 4B affinity gel. The purified enzyme showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The effects of four different antibiotics (isepamicin sulfate, meropenem, chloramphenicol, and thiamphenicol glisinat hydrochloride) were investigated on the purified enzyme. K(i) value and type of inhibition were determined by means of Lineweaver-Burk graphs and regression analysis graphs. Isepamicin sulfate inhibited the enzyme activity (I(50) value, 2.1 mM; K(i) value, 1.7 mM), whereas thiamphenicol glisinat hydrochloride activated the G6PD dose dependently. Other drugs showed no inhibition and activation effect. In addition, the effects of isepamicin sulfate on the activities of G6PD, glutathione reductase (GR), superoxide dismutases (SOD), glutathione peroxidase (GPx), catalase (CAT), and glutathione S-transferase (GST) and MDA concentrations were examined in Sprague-Dawley rat erythrocytes in vivo. A marked alteration in the activities of these enzymes and MDA levels may be the result of oxidative stress in the rats receiving isepamicin sulfate.

Evaluation of effect of some corticosteroids on glucose-6-phosphate dehydrogenase and comparative study of antioxidant enzyme activities

Corticosteroids are anti-inflammatory drugs that are similar to the natural corticosteroid hormones produced by the cortex of the adrenal glands. The objective of this study was to scrutinize effects of some corticosteroids on glucose-6-phosphate dehydrogenase (G6PD) and some antioxidant enzymes. Initially, G6PD was purified from human erythrocytes by using ammonium sulphate precipitation and affinity chromatography. The two drugs, dexamethasone phosphate and prednisolone, investigated on the purified enzyme inhibited the enzyme activity. Comparative in vivo studies were performed to determine the effects of dexamethasone phosphate on the antioxidant enzyme activities using Spraque-Dawley rats. G6PD and catalase (CAT) activities were found significantly lower than in the control, whereas glutathione peroxidase (GP) activity was significantly increased in the erythrocytes of rats the receiving drug; glutathione reductase (GR) activity was unaffected. The results imply that dexamethasone phosphate may affect oxidative stress by changing antioxidant enzyme activities.

DCFH2 interactions with hydroxyl radicals and other oxidants--influence of organic solvents

The oxidation of 2',7'-dichlorofluorescin (DCFH(2)) is widely used as a measure to detect the generation of reactive oxygen species (ROS) and to analyze oxidative stress. Other factors beside commonly known radicals may influence the results of such measurements. Therefore, the effects of H(2)O(2), KMnO(4,) decomposition products of AAPH, ethanol and DMSO, antioxidants like ascorbic acid, different ferrous ion chelates, and heme-containing proteins like cytochrome c, myoglobin, hemoglobin, and horseradish-peroxidase were comparatively analyzed with respect to their impact on DCFH(2) oxidation. The study evaluates the effects of various oxidants with different oxidative potentials regarding their ability to induce DCF-fluorescence. Furthermore, we analyzed the inhibitory effect of organic solvents like ethanol or DMSO on the oxidation of DCFH(2) by hydroxyl radicals. The results of our study indicate that the potential of an oxidant does not always correlate with its efficiency to generate DCF-fluorescence.

Effect of leptin on peroxidation and antioxidant defense in ethanol-supplemented Mus musculus heart

The aim of the study was to evaluate the effect of exogenous mouse leptin on ethanol-induced cardiac toxicity in mice. Administering ethanol (6.32 g/kg body weight p.o.) to 4-week-old healthy mice for 45 days resulted in significantly elevated plasma levels of leptin, lactate dehydrogenase (LDH), cardiac lipid hydroperoxides (LOOH) and thiobarbituric acid reactive substances (TBARS) and significantly decreased cardiac superoxide dismutase, catalase, vitamin C, vitamin E, reduced glutathione and glutathione-dependent enzyme levels (glutathione peroxidase and glutathione S-transferase). Subsequent to the experimental induction of toxicity (i.e., after the initial period of 30 days) exogenous leptin was administered (230 microg/kg body weight i.p.) every alternate day for 15 days along with the daily dose of ethanol. Leptin administration to ethanol-treated mice significantly elevated the levels of plasma leptin, LDH and cardiac LOOH, TBARS, whereas the activity of antioxidant enzymes and the concentrations of vitamins C and E were further decreased significantly. These findings were consistent with our histological observations, confirming that leptin enhances cardiac toxicity in ethanol-supplemented mice.

Protective effect of resveratrol on ethanol-induced lipid peroxidation in rats

AIM

Chronic ethanol treatment induces an increase in oxidative stress. As polyphenolic compounds are potent antioxidants, we aimed to examine whether dietary supplementation of resveratrol may attenuate lipid peroxidation, the major end-point of oxidative damage resulting from chronic ethanol administration.

METHOD

Three groups of male Wistar rats were used. The first group served as control and received a daily intraperitoneal injection of 0.9% saline. The second group of rats was daily injected with 35% ethanol at 3 g/kg body weight. The third group was given the same dose of ethanol and supplemented with resveratrol (5 g/kg) in the standard diet. Malondialdehyde (MDA), an indicator of oxidative stress, was measured in the liver, heart, brain, and testis.

RESULTS

At the end of a 6 weeks treatment period, MDA levels were significantly increased by 51.5, 53.7, 72.7, and 40.5% in the liver, heart, brain, and testis, respectively. However, when ethanol treated rats were given resveratrol the increase in MDA levels was significantly reduced in all organs to nearly those of control rats.

CONCLUSION

Resveratrol is able to inhibit the ethanol-induced lipid peroxidation and have protective effect against oxidative injury.

RESPONSES TO CARDIOVASCULAR DRUGS DURING ALCOHOL WITHDRAWAL

AIM

To present findings on the kinetics and dynamics of cardiovascular drugs during alcohol withdrawal (AW), compared with that observed in remission.

METHOD

Studies were reviewed and summarized.

RESULTS

A single-dose study in alcoholic patients with propranolol, a beta-adrenergic antagonist, showed that the negative inotropic effect was decreased and the bradycardiac effect increased during AW as compared with during early remission. The hypotensive effect of isosorbid dinitrate, commonly used as a vasodilatator, was weaker at the onset of AW, being associated with the decreased bioavailability of the drug. Verapamil, which is a L-type Ca2+ channel antagonist, produced a bradycardiac effect at the onset of AW, but no effect was observed in early remission. The effect was probably due to changes in L-type Ca2+ channels because no differences in verapamil concentrations between AW and early remission were observed.

CONCLUSION

Taken together, AW modifies the dynamics and kinetics of cardiac drugs, which may have an impact on the treatment of alcoholic patients with cardiac diseases.

Alcoholic myopathy: lack of effect of zinc supplementation

A chronic form of myopathy has been described in alcoholics, characterized by atrophy of type II fibers, due both to reduced protein synthesis and increased protein breakdown. Increased production of reactive oxygen species could probably play a role in increased protein breakdown. In addition, treatment with zinc might be beneficial, since it acts as a cofactor of several enzymes involved in the synthesis of proteins and antioxidants as copper-zinc-superoxidedismutase (SOD) and selenium dependent glutathione peroxidase (GPX). Based on these facts, we analyze the relative and combined effects of ethanol, protein malnutrition and treatment with zinc, 227 mg/l in form of zinc sulphate, on muscle changes in 8 groups of adult Sprague-Dawley rats fed following the Lieber-de Carli model during 5 weeks. We also study the association between muscle histological changes and the activity of GPX, SOD and lipid peroxidation products (MDA), with hormones such as IGF-1, and with trace elements involved in antioxidant systems and/or in lipid peroxidation, such as selenium, copper, zinc, and iron. We found type IIa and IIb fiber atrophy in the alcoholic animals, especially in the low-protein fed ones. This effect was mainly due to protein deficiency. Zinc played no role at all. Muscle iron increased in ethanol, low protein fed rats, either with or without zinc, and was directly related with muscle MDA levels, which in turn were related with muscle atrophy, as was also found for serum IGF-1 levels. Ethanol was the main responsible for all these changes, although protein undernutrition also played an independent role in MDA levels. A positive interaction between ethanol and protein deficiency on serum IGF-1 was also detected. These results suggest that both protein deficiency and ethanol contribute to muscle atrophy observed in alcoholized rats; this atrophy is associated with increased lipid peroxidation and muscle iron overload. Treatment with zinc sulphate confers no benefit.

Du-zhong (Eucommia ulmoides Oliv.) cortex water extract alters heme biosynthesis and erythrocyte antioxidant defense system in lead-administered rats

This study examined the ameliorative effect of a Du-zhong (Eucommia ulmoides Oliv.) cortex water extract (DzCw) on heme biosynthesis and erythrocyte antioxidant enzyme activities in lead (Pb)-administered rats. Male rats were divided into three groups: normal control group, Pb control group (Pb), and DzCw-administered Pb group (Pb + DzCw). The Pb (25 mg/kg of body weight) was administered orally once a week for 4 weeks, while the DzCw was administered orally at a dosage of 0.139 g of DzCw/kg of body weight/day. DzCw administration significantly lowered plasma Pb concentration compared with the Pb group. Furthermore, the blood hematocrit and hemoglobin levels were significantly higher in the Pb + DzCw group than in the Pb group. Although the blood and hepatic delta-aminolevulinic acid dehydratase (ALAD) activities were significantly lower in the Pb group compared with the normal control group, both ALAD activities was normalized with the administration of DzCw. The erythrocyte superoxide dismutase and catalase activities were significantly higher in the Pb group than in the normal control group, whereas the glutathione peroxidase activity and glutathione level were lowered by Pb administration compared with the normal group. However, the administration of DzCw was found to enhance the antioxidant defense system and significantly lower lipid peroxidation levels in erythrocytes compared with the Pb group. These results indicate that the DzCw administration alleviated the Pb-induced oxidative stress in the erythrocytes through elevating the blood and hepatic ALAD activity and enhancing the antioxidant enzyme activities.

Oxidative stress in alcohol-induced rat parotid sialadenosis

This study evaluated the effect of chronic ethanol consumption on the oxidative status of rat parotid and submandibular glands. To identify the endogenous response to ethanol ingestion, the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were determined. In addition, the antioxidant alpha-tocopherol was supplied to the animals in order to estimate its action in ethanol-associated glandular damage. The thiobarbituric acid reactive substances (TBARS), and the protein carbonyl (PC) content, both markers of cellular oxidative stress on lipid and protein structures, respectively, were recorded. Animals subjected to alcohol ingestion showed a low body growth rate with concomitant enlargement of absolute and relative parotid wet weight, compared with pair-fed calorie-controlled rats. Parotid glands of ethanol-treated animals showed increased SOD and GPx activity, and alpha-tocopherol was able to reduce their activities to the control levels. TBARS and PC were enhanced after chronic ethanol treatment in rat parotids. Supplemental alpha-tocopherol suppressed the oxidative ethanol-induced damage in lipid without affecting induced protein oxidation. Submandibular glands revealed no alterations in the weight, enzymatic and oxidative parameters tested due to ethanol and/or alpha-tocopherol ingestion. These findings indicate the involvement of oxidative stress in parotid gland sialadenosis due to ethanol consumption and the capability of alpha-tocopherol to halt lipid damage, although this low-molecular antioxidant compound leads to neither increased glandular weight nor protein oxidation in ethanol-induced parotid alterations.

Effects of antiemetic drugs on glucose 6-phosphate dehydrogenase and some antioxidant enzymes

The aim of this study was to investigate effect of antiemetics on G6PD and antioxidant enzymes. Antiemetics are currently being used to reduce or prevent nausea and vomiting in patients. This is the first study to show effect of antiemetics on glucose-6-phosphate dehydrogenase (G6PD) and antioxidant enzyme activities. For in vitro studies, G6PD was purified from human erythrocyte, 10, 26-fold in a yield of 51.3% by using ammonium sulphate precipitation and 2',5'-ADP-Sepharose 4B affinity gel. The purified enzyme showed a single band on sodium dodecyl sulfate-polyacrilamide gel electrophoresis (SDS-PAGE). The effects of four different antiemetics (granisetron hydrochloride, ondansetron hydrochloride, metoclopramide hydrochloride, trimethobenzamide hydrochloride) were investigated on the purified enzyme. Granisetron hydrochloride and ondansetron hydrochloride inhibited the enzyme activity (Ki values; 5.05 mM and 0.034 mM, I50 values; 3.9 mM and 0.036 mM, respectively). Metoclopramide hydrochloride, trimethobenzamide hydrochloride showed no inhibition effects. In addition, in vivo studies, effects of ondansetron hydrochloride on the G6PD, glutathione reductase (GR), glutathione peroxidase (GPx) and catalase (CAT) were examined in the rat erythrocytes. G6PD (49% of control), GR (55% of control), CAT (60% of control) activities in erythrocytes were significantly decreased whereas GPx (183% of control) was significantly increased. A marked alteration in these enzymes may be result of oxidative stress in the rats receiving ondansetron hydrochloride.

Ethanol, wine, and experimental cardioprotection in ischemia/reperfusion: role of the prooxidant/antioxidant balance

It is now well established that oxidative stress resulting from reactive oxygen species (ROS) that are generated in cardiac myocytes subjected to ischemia/reperfusion plays a causative role in the development of heart failure and may contribute to promote cell death. During the last decade, several groups have reported that, in animal models of myocardial ischemia/reperfusion, certain nutrients, including ethanol and nonethanolic components of wine, may have a specific protective effect on the myocardium, independent of the classical risk factors implicated in vascular atherosclerosis and thrombosis. Mechanisms through which the consumption of alcoholic beverages protects against ischemia-induced cardiac injury are still unknown. One major open question is whether ethanol and nonethanolic components of wine are cardioprotective, at least in part, by interfering with the myocardial prooxidant/antioxidant balance. Important concepts, such as cardiac preconditioning, are now entering the field of nutrition, and recent experimental evidence suggests that ethanol and/or nonethanolic components of wine might exert preconditioning effects in animal models of myocardial ischemia/reperfusion. There is no doubt that such an observation, if confirmed in human subjects, might open new perspectives in the prevention and treatment of ischemic coronary heart disease.

Altered cardiovascular responses to nitrosorbide in alcohol withdrawal

The cardiovascular effects and pharmacokinetics of a single dose (20 mg sublingually) of isosorbide dinitrate (ISDN) were studied in 9 alcohol-dependent men during alcohol withdrawal syndrome (AW) on day 1 and after the resolution of AW on day 10. At the onset of AW, ISDN and its metabolites caused a hypotensive effect, which was increased on day 10, while no differences in ISDN-induced decrease in stroke volume were observed. Tachycardiac response to ISDN was more pronounced at onset of AW. On day 10, the AUC(0-1.5 h), C(max) and t((1/2)) of ISDN were increased compared with day 1. The results of this study suggest that nitric oxide may modulate the cardiovascular system in AW.

Lead induced oxidative damage and its response to combined administration of alpha-lipoic acid and succimers in rats

Alpha-lipoic acid (LA) has been reported to be highly effective in improving the thiol capacity of the cells and in reducing lead induced oxidative stress. These results suggested its possible role as a therapeutic intervention of lead poisoning in combination with a chelator. We investigated the effects of LA, either alone or when administered in combination with succimer (meso 2,3-dimercaptosuccinic acid; DMSA or one of its analogue monoisoamyl DMSA), in influencing the lead induced alterations in haem synthesis pathway, hepatic, renal and brain oxidative stress and lead concentration from blood and soft tissues. The results suggest a significant lead induced inhibition of delta-aminolevulinic acid dehydratase (ALAD), reduction in glutathione (GSH) and an increased zinc protoporphyrin (ZPP) level in blood, indicating altered heme synthesis pathway. Both the thiol chelators were able to increase blood ALAD activity and GSH level towards normal. The most prominent effect on blood ALAD activity was however observed when monoisoamyl DMSA (MiADMSA) was co-administered with LA. Lead exposure produced significant depletion of hepatic GSH, while, oxidized glutahione (GSSG), thiobarbituric acid reactive substances (TBARS) and catalase activity increased significantly, suggesting hepatic oxidative stress. All the treatments were able to increase hepatic GSH and reduce GSSG levels, while, TBARS level reduced significantly in animals administered LA and MiADMSA, individually or in combination. Lead induced increase in renal GSSG, TBARS levels and catalase activity, were effectively reduced by LA, while, the two chelators when administered alone were effective only in reducing GSSG and catalase activity. The most prominent beneficial effects, however, were observed in animals treated concomitantly with LA and one of the chelators (DMSA or MiADMSA). Brain GSH and GSSG levels decreased moderately while superoxide dismutase (SOD) activity remained statistically unaltered on lead exposure. Brain catalase activity, on the other hand, increased significantly. Administration of LA was effective in reducing these alterations in the brain, however, the best effects were achieved in animals co-administered LA and one of the thiol chelators. The results point to a significant beneficial role of LA in the recovery of altered biochemical variables both during monotherapy and when given in combination with succimer. It however, showed no chelating properties in decreasing lead burden from blood, liver and kidneys except for a significantly more pronounced decrease in brain lead concentration in animals administered LA plus thiol chelators, compared to the effects of chelating agents alone. This is an interesting and notable observation, which requires further exploration. The results thus provide evidence of an encouraging role of LA when given in combination with a thiol chelator in the therapeutic intervention of lead poisoning, particularly in reducing the oxidative stress and brain lead concentration.

Chronic ethanol and nicotine interaction on rat tissue antioxidant defense system

Ethanol consumption and cigarette smoking are common in societies worldwide and have been identified as injurious to human health. This study was undertaken to examine the interactive effects of chronic ethanol and nicotine consumption on the antioxidant defense system in different tissues of rat. Male Fisher-344 rats were divided into four groups of five animals each and treated for 6.5 weeks as follows: (1) Control rats were administered normal saline orally; (2) ethanol (20% [wt./vol.]) was given orally at a dose of 2 g/kg; (3) nicotine was administered subcutaneously at a dose of 0.1 mg/kg; and (4) a combination of ethanol plus nicotine was administered by the route and at the dose described above. The animals were killed 20 h after the last treatment, and liver, lung, kidney, and testes were isolated and analyzed. Chronic ingestion of ethanol resulted in a significant depletion of glutathione (GSH) content in liver, lung, and testes, whereas chronic administration of nicotine significantly depleted GSH content in liver and testes. The combination of ethanol plus nicotine resulted in a significant depletion of GSH content in liver, lung, and testes. Ethanol, nicotine, or a combination of ethanol plus nicotine significantly increased superoxide dismutase (SOD) activity in liver and decreased SOD activity in kidney. Ethanol, nicotine, or a combination of ethanol plus nicotine significantly decreased catalase (CAT) activity in liver and increased CAT activity in kidney and testes. Chronic ingestion of ethanol resulted in a significant decrease in glutathione peroxidase (GSH-Px) activity in liver and kidney, whereas a combination of ethanol plus nicotine increased GSH-Px activity in liver and decreased GSH-Px activity in kidney and testes. Ethanol, nicotine, or a combination of ethanol plus nicotine significantly increased lipid peroxidation, respectively, in liver. It is suggested that prolonged exposure to ethanol and nicotine produce similar, and in some cases additive, oxidative tissue injuries in rat.

Mitochondrial oxidative damage and myocardial fibrosis in rats chronically intoxicated with moderate doses of ethanol

Mitochondrial oxidative balance and myocardial fibrosis were investigated in pair-fed rats received ethanol (3%) or saccharose in drinking water for 8 weeks. The concentrations of glutathione, malondialdehyde, protein carbonyls and sulfhydrils were determined. The presence and distribution of fibronectin were detected by immunohistochemistry. The myocardial concentrations of reduced glutathione and protein sulfhydrils were lower in ethanol treated rats. The oxidised/reduced glutathione ratio, the levels of malondialdehyde and protein carbonyls were higher in ethanol-treated rats. The mitochondrial amount of proteins, glutathione and protein sulfhydrils were lower in ethanol treated rats, whereas the content of protein carbonyls and malondialdehyde were higher. Accumulation of fibronectin was detected at subepicardial and subendocardial districts in ethanol-treated rats, with moderate degree of fibrosis in 20% of the cases. In conclusion, moderate ethanol consumption is associated with oxidative damage to heart mitochondria and fibronectin deposition. These oxidative and ultrastuctural changes may be assumed as basic alterations in the development of alcoholic cardiomyopathy.

Effect of moderate alcohol intake on lipid peroxidation in plasma, erythrocyte and leukocyte and on some antioxidant enzymes

Plasma, erythrocyte and leukocyte lipid peroxidation, erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and plasma gamma-glutamyl transferase (GGT) levels were investigated in 36 healthy non-drinkers aged between 18-55 years (mean 38.7) and 72 alcohol drinkers aged between 20-48 years (mean 35.3) in order to determine the oxidative effect of alcohol. Erythrocyte lipid peroxidation of the drinkers (measured in terms of MDA) was found to be significantly (P < 0.05) reduced compared to that of controls. However, when Tukey-HSD and F test with ANOVA were performed, that significance disappears in those who consume less than 140 g of alcohol per day and persists in those who consume more than 140 g of alcohol per day (P < 0.05). Plasma GGT level was significantly increased compared to that of controls (P < 0.001). Also, there was a significant (P = 0.01) correlation between serum GGT level and the amount of alcohol. There were no significant differences between all the other parameters of both groups. Reduced lipid peroxidation of erythrocytes without any accompanying increase in the activities of antioxidant enzymes shows that another mechanism might be responsible for this finding. This mechanism was thought to be an alteration in lipid composition of erythrocyte membranes.

Chronic ethanol ingestion-induced changes in open-field behavior and oxidative stress in the rat

The effects of chronic ethanol intoxication on the open-field behavior, on antioxidant enzyme activities, and the degree of lipid peroxidation were investigated. Rats consuming a liquid diet containing 7% ethanol for 4, 7, 14, or 21 days exhibited a significantly decreased ambulation activity, accompanied by a reduced frequency and duration of explorative rearing in an open-field task 4, 7, and 14 days after chronic ethanol ingestion, whereas presumed adaptation to the neurologic effects of ethanol was observed on day 21. Changes in the activities of glutathione peroxidase (GSH-Px): glutathione reductase (GSH-R), and catalase, and in the content of reduced glutathione (GSH) in blood samples were determined by means of biochemical methods. The degree of lipid peroxidation was measured via thiobarbituric acid assays. Chronic ethanol ingestion elicited a significant increase in GSH-Px activity (by a maximum of approximately 32% on day 14), whereas opposite alterations in GSH-R and catalase activities were recorded (49% of the control value on day 4 and 17% on day 21, respectively). Highly elevated contents of thiobarbituric acid reactive substances reflected extensive lipid peroxidation processes throughout the experiment. These changes indicate that ethanol toxicity induces profound changes in explorative behavior, mediated, at least partly, by changes in the free radical metabolism.

Alcoholic beverages and lipid peroxidation: relevance to cardiovascular disease

Overall there is good evidence that alcohol consumption induces oxidative stress, and leads to lipid peroxidation, effects which have been linked to alcohol-related toxicity and disease and may be relevant to alcoholatherosclerosis interrelationships. On the other hand, a protective effect of light to moderate alcohol consumption against cardiovascular disease is well recognized, with the further hypothesis that red wine offers extra cardiovascular protection due to its rich content of antioxidant phenolic compounds. Although this hypothesis is given some credence from in vitro data, controlled studies in humans have produced conflicting results. Clearly, the equally well described pro-oxidant effects of alcohol and its metabolism have been insufficiently considered in the pursuit of what to many is an intuitively attractive hypothesis. Further studies are required to determine if red wine phenolics are actually absorbed from the gut and whether they offer any overall antioxidant protection in vivo. The hypothesis that red wine offers extra cardiovascular protection compared to other alcoholic beverages is not proven and must await the outcome of studies in which the full spectrum of the pro-oxidant and antioxidant effects of alcoholic beverages are duly considered. In the absence of such studies, there are no grounds at present for the promotion of the consumption of alcoholic beverages on the basis of their putative "antioxidant" properties.

Running exercise may reduce risk for lung and liver cancer by inducing activity of antioxidant and phase II enzymes

The effects of exercise, ethanol, and exercise plus ethanol-treatments on activity of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) and UDP-glucuronosyl transferase (UDP-GT) in lung and liver were investigated. All treatments induced SOD and CAT activity in the lung while CAT activity was enhanced only by the combined treatments in the liver. Ethanol reduced hepatic SOD activity, while with the combined treatment SOD was normal. Exercise enhanced UDP-GT activity in liver and lung while ethanol had no effect and GST activity was induced in the liver by the combined treatment. Thus exercise may reduce risk for lung and hepatic cancer and prevent an ethanol-induced increase in risk for hepatic cancer by enhancing activity of antioxidant and phase II enzymes.

Response of cardiac antioxidant system to alcohol and exercise training in the rat

Recent evidence has shown that alcohol as well as exercise induces oxidative stress. However, the combination of both on the cardiac antioxidant system is not known. This study investigates the interactive effects of exercise training and chronic ethanol consumption on the antioxidant system of the rat heart. Male Fisher-344 rats were treated as follows: 1) sedentary control (SC); 2) exercise training (ET) for 6.5 weeks; 3) ethanol (2 g/kg, PO) for 6.5 weeks, and 4) ET plus ethanol for 6.5 weeks. Rats were sacrificed and hearts were isolated. Glutathione (GSH), oxidized glutathione (GSSG), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), and lipid peroxidation (MDA) were determined in heart tissues. SOD and GSH-Px activities were significantly increased 118% and 148% of SC, respectively, due to ET. GSH level increased 118% of SC in ET rats. GSH-Px activity increased 118% of SC whereas SOD activity and CuZn-SOD protein level and GR activity decreased 87%, 71%, and 90% of SC due to chronic ethanol administration. GSH level decreased 87% of SC and lipid peroxidation increased 149% of SC due to ethanol consumption. GSH-Px activity and GSH levels increased 143% and 130% of SC due to combination of ET and ethanol. This study suggests that ET and chronic ethanol ingestion augments the antioxidant enzyme activity and GSH levels in the heart. This combination reduced the extent of ethanol-induced lipid peroxidation. The data suggest that ET may reduce the extent of the damage caused by ethanol consumption on the myocardium.

Ethanol-induced oxidative stress and enzymatic defenses in cultured fetal rat hepatocytes

Previously, we have documented an ethanol (E)-induced oxidative stress (OS) in cultured fetal rat hepatocytes (FRH). The cause of this is uncertain, but an inhibition of key antioxidant enzymes could be a/the factor. OS was also observed in fetal liver (FL) during in utero E exposure, but not in maternal liver, a difference that might be related to selectively lower enzymatic defenses in the fetus. Here, we record effects of E on activities of catalase (Cat), superoxide dismutase (Cu, Zn SOD and Mn SOD), glutathione peroxidase (GPX), and glutathione-S-transferase (GST) in FRH isolated from 20-day-old fetuses and exposed to E (2 mg/ml) for up to 24 h and we compare these to adult rat liver data. E treatment decreased fetal liver reduced glutathione (GSH) pools by 23% (p < 0.05) and increased malondialdehyde (MDA) by 14% (p < 0.05) within 24 h of E exposure. E caused an increase in fetal liver Cat by 18%, 32%, and 47% by 3, 6, and 24 h of E, respectively (p < 0.05). A 24-h E exposure increased Cu, Zn SOD by 22% (p < 0.05) and Mn SOD by 21% (p < 0.05). A 24 h E treatment increased GPX by 18% (p < 0.05) and GST by 17% (p < 0.05). Cat in whole FL was 26% of adult (p < 0.05) whereas Cu, Zn SOD and Mn SOD in whole FL were 12% and 11% of adult levels (p < 0.05). GPX and GST in FL were 11% and 28% of adult values (p < 0.05). It is concluded that in FRH, E-induced OS is not caused by impaired activities of these enzymes, but their low basal activities (vs. adult) may predispose the fetus to OS.

Red wine effects on peroxidation indexes of rat plasma and erythrocytes

Moderate wine intake has been associated with low risk for cardiovascular disease, possibly due to its polyphenol content. We investigated the influence of these compounds on peroxidative indices of blood. Forty Sprague-Dawley rats were divided into four groups given the same AIN-76 diet but different types of isocaloric beverage: red wine, alcohol and dealcoholated wine and water with added sucrose. Rats consumed about 35 ml day(-1) of beverage and 17 g day(-1) of diet for a total of about 95 kcal day(-1). Plasma alpha-tocopherol was higher in the alcohol group and the peroxidation kinetic slope was higher in the control and dealcoholated wine groups. Ascorbic acid in whole blood was higher in the alcohol group than the others. Erythrocytic glutathione peroxidase activity was lower in the red wine group. The other variables studied, were not significantly different in the four groups. Despite the significant differences observed, the oxidative status of blood does not appear seriously altered by heavy ingestion of wine and thus of polyphenols. Probably the balanced diet and adequate intake of micronutrients were sufficient to counteract any oxidative damage.

Mitochondrial respiratory activity and superoxide radical generation in the liver, brain and heart after chronic ethanol intake

Functional characteristics of mitochondria isolated from liver, brain and heart were studied in ethanol-fed rats using ethanol administration in drinking water as a model of moderate alcohol intoxication. Our results show a slight decrease in liver cytochrome aa3 content, the mitochondrial alteration which is most consistently observed during chronic ethanol feeding. In liver and heart mitochondria, ethanol consumption led to an increase in state 3 respiration with NAD(+)-linked substrates, whereas no changes were apparent in respiration rates with succinate as substrate. However a decrease was found in state 3 respiration with succinate in brain mitochondria isolated from ethanol-fed rats. Submitochondrial particles (SMP) were used to study the superoxide radical (O2-.) production at the level of antimycin-inhibited regions of the respiratory chain. It appears that there is no clear correlation between ethanol effects on respiration and O2-. production. Whereas O2-. generation remained unchanged in heart mitochondria, an elevation of O2-. generation was observed in brain mitochondria, and in contrast, the rate of O2-. production was decreased in liver mitochondria of the ethanol-group in comparison to the control-group. Our findings support a tissue specificity for the toxic effects of ethanol towards the mitochondria and indicate that mitochondrial free radical mechanisms are involved in ethanol-induced toxicity in the brain.