Effect Of Chronic Ethanol Ingestion Research Articles

Chronic Ethanol Intake Alters Circadian Period‐Responses to Brief Light Pulses in Rats

Although chronic alcohol intake is associated with widespread disruptions of sleep‐wake cycles and other daily biological rhythms in both human alcoholics and experimental animals, the extent to which the chronobiological effects of alcohol are mediated by effects on the underlying circadian pacemaker remains unknown. Nevertheless, recent studies indicate that both adult and perinatal ethanol treatments may alter the free‐running period and photic responsiveness of the circadian pacemaker. The present experiment was designed to further characterize the effects of chronic ethanol intake on the response of the rat circadian pacemaker to brief light pulses. Ethanol‐treated and control animals were exposed to 15‐min light pulses during either early or late subjective night on the first day of constant darkness following entrainment to a 12:12 light‐dark cycle. Relative to pulses delivered during early subjective night and to “no‐pulse” conditions, light pulses delivered during late subjective night resulted in period‐shortening after‐effects under constant darkness, but only in control animals, not in ethanol‐treated animals. These results indicate that chronic ethanol intake reduces the responsiveness of the circadian pacemaker to acute photic stimulation, and suggest that the chronobiological disruptions seen in human alcoholics are due in part to alterations in circadian pacemaker function.

The effects of chronic exposure to ethanol and cigarette smoke on the level of reduced glutathione and malondialdehyde in rat kidney.

The aim of this study was to investigate the effects of chronic ethanol intake and cigarette smoke exposure on rat kidney. The animals were divided into four experimental groups: (1) the control group (C), (2) the ethanol group (E), (3) the cigarette smoke group (CS), and (4) the cigarette smoke plus ethanol group (CS+E). Apart from the control group, these were treated with ethanol and/or cigarette smoke for 6 months. The animals were killed and the kidneys removed to determine the levels of reduced glutathione (GSH) and malondialdehyde (MDA) and for histopathological analysis. The levels of GSH/g wet tissue were 1.58+/-0.09 micro mol, 0.91+/-0.05 micro mol, 1.14+/-0.06 micro mol, and 0.82+/-0.04 micro mol for C, E, CS, and CS+E, respectively. In groups of E, CS, and CS+E, the GSH values were significantly lower than that of group C animals ( P<0.05). Although, we detected lower GSH levels in the CS+E than the CS group ( P<0.05), a significant difference in GSH levels between CS+E and E was not observed. The levels of MDA/g wet tissue were 40.1+/-3.4 nmol, 71.4+/-2.8 nmol, 64.0+/-3.6 nmol, and 76.5+/-4.3 nmol, for C, E, CS and CS+E, respectively. In E, CS, and CS+E, the MDA values were significantly higher than in group C ( P<0.05). The increase in MDA levels in CS+E were not significantly different from groups E or CS. Histopathological analysis of the kidney slices showed severe degeneration of the tissues. Advanced hydropic degeneration of kidney tubules was clearly observed in the CS group. In group E, advanced tubular and interstitial damage, mononuclear cell infiltration and tubular thyroidization were clearly visible. In group CS+E, an intense inflammatory cell infiltration was detected under the transitional epithelium. We conclude that chronic exposure to ethanol and cigarette smoke may cause an oxidative burst in rat kidney by increasing the formation of reactive oxygen species.

Effects of Chronic Ethanol on Hepatic and Renal CYP2C11 in the Male Rat: Interactions with the Janus-Kinase 2-Signal Transducer and Activators of Transcription Proteins 5b Pathway

Chronic alcohol intake in male rats results in: 1) demasculinization of the GH pulse pattern; 2) reduced serum testosterone concentrations; and 3) decreased expression hepatic CYP2C11. Hepatic CYP2C11 expression is regulated by the male pattern of GH through the Janus-kinase/signal transducer and activators of transcription proteins (JAK/STAT) signal transduction pathway in the male rat. Renal CYP2C11 is regulated by testosterone, not GH. The involvement of the JAK/STAT5b signal transduction pathway in renal CYP2C11 signaling has not been studied. We tested the hypothesis that ethanol reduces CYP2C11 levels by interfering with the JAK/STAT5b pathway. Using a total enteral nutrition (TEN) model to feed rats a well-balanced diet, we have studied the effects of chronic ethanol intake (21 d) on hepatic and renal JAK/STAT pathway of adult male rats (8-10/group). We found decreased hepatic and renal expression of CYP2C11 in ethanol-fed rats with concomitant decreases in STAT5b and phospho-STAT5b, decreased in vitro hepatic STAT5b binding to a CYP2C11 promoter element and no effects on hepatic GHR levels. Ethanol caused tissue specific effects in phospho-JAK2 and JAK2, with increased levels in the liver, but decreased JAK2 expression in the kidney. We conclude that ethanol suppression of CYP2C11 expression is clearly associated with reductions in STAT5b levels, but not necessarily in reductions of JAK2 levels. The mechanisms underlying ethanol-induced suppression of STAT5b is yet to be determined, as is the question of whether this is secondary to hormonal effects or a direct ethanol effect.

Phosphatidylethanolamine N-methyltransferase activity is increased in rat intestinal brush-border membrane by chronic ethanol ingestion.

Phosphatidylethanolamine N-methyltransferase (PEMT) catalyses the synthesis of phosphatidylcholine from phosphatidylethanolamine. The aim of this study was to evaluate the effect of chronic ethanol ingestion on PEMT activity in the jejunal brush-border membrane (BBM) of adequately nourished rats. For this purpose, rats were fed a liquid diet containing ethanol [ethanol-fed group (EFG)] or an isocaloric liquid diet without ethanol [pair-fed group (PFG)] for 4 weeks. Diet ingestion, body weight, nitrogen balance and urinary creatinine excretion were monitored during the experimental period, and serum transferrin levels were determined at the end. BBM was isolated for the determination of PEMT activity. PEMT activity was significantly increased in the jejunal BBM of the EFG. Nutritional parameters, however, did not differ between groups. The increase in PEMT activity may be attributed exclusively to chronic ethanol ingestion, since a major nutritional deficit was excluded.

Ethanol-dependent induction of bilirubin UDP-glucuronosyl-transferase in rat liver is mediated by Kupffer cells

Recently we have reported that bilirubin UDP-glucuronosyltransferase (UGT1A1) is induced in rat liver by chronic ethanol treatment. Several studies have shown that Kupffer cells play a central role in the mediation of various hepatic effects of chronic alcohol consumption. In the present work, the participation of Kupffer cells in the ethanol dependent induction of UGT1A1 was investigated. A group of rats was pretreated with gadolinium chloride, a known Kupffer-cell-depleting agent. We compared the effect of chronic ethanol ingestion on UGT1A1 expression in the liver of normal and gadolinium chloride treated rats. The effect of ethanol on bilirubin glucuronidation was completely prevented in Kupffer cell deficient rats. The western and northern blot analyses showed that the increase of both the protein and mRNA of UGT1A1 was prevented in these animals. These results suggest that Kupffer cells play a major role in the mediation of ethanol-stimulated induction of UGT1A1 in liver parenchymal cells.

Effects of chronic ethanol ingestion on nutritional status in three successive generations of rats

The purpose of this study was to determine the effects of chronic ethanol ingestion on the nutritional status of three successive generations of rats. Ethanol treated rats received ad libitum 5, 10 and 15% ethanol in their drinking fluid over 3 successive weeks. Then, a concentration of 20% was maintained for 5 additional weeks and until the end of the experimental period. Males and females in the ethanol treated group were mated to obtain the 1st generation offspring. Subsequently, females and males from the 1st generation offspring were mated to obtain the 2nd generation offspring. Finally, males and females of the 2nd generation offspring were mated to obtain the 3rd generation offspring of ethanol treated rats. Another group served as control and received only water, a standard rat chow diet, and was handled in the same way as the other experimental groups. The results indicated that the body weight of (21-days post-natal) ethanol treated rats was significantly lower than that of the control group. Intestinal length/body weight ratios of (6-months post-natal) ethanol treated rats, were significantly greater in the 1st and 2nd generation, but the 3rd generation ethanol treated rats tended to attain weights and ratios comparable to controls. In both the 1st and 2nd generation offspring, the mean total calorie consumption was not different from that of the control group, but the proportion of calories from chow was reduced. Conversely, the 3rd generation offspring consumed more calories. Furthermore, the body weight at the end of the experimental period in the 1st and 2nd generation offspring was lower than the control group, but the body weight of the 3rd generation was not different in the two groups. In conclusion these results indicate a possible effect of ethanol ingestion on the nutritional status of 1st and 2nd generation offspring.

Effect of chronic ethanol ingestion and exercise training on skeletal muscle in rat

The aim of this study was to investigate the interactive effects of exercise training and chronic ethanol consumption on metabolism, capillarity, and myofibrillar composition in rat limb muscles. Male Wistar rats were treated in separate groups as follows: non exercised-control; ethanol (15%) in animals’ drinking water for 12 weeks; exercise training in treadmill and ethanol administration plus exercise for 12 weeks. Ethanol administration decreased capillarity and increased piruvate kinase and lactate dehydrogenase activities in white gastrocnemius; in plantaris muscle, ethanol increased citrate synthase activity and decreased cross-sectional area of type I, IIa, and IIb fibres. Exercise increased capillarity in all four limb muscles and decreased type I fibre area in plantaris. The decreased capillarity effect induced by ethanol in some muscles, was ameliorated when alcohol was combined with exercise. While alcoholic myopathy affects predominantly type IIb fibres, ethanol administration and aerobic exercise in some cases can affect type I and type IIa fibre areas. The exercise can decrease some harmful effects produced by ethanol in the muscle, including the decrease in the fibre area and capillary density.

Reduced Folate Carrier: Tissue Distribution and Effects of Chronic Ethanol Intake in the Micropig

Reduced Folate Carrier: Tissue Distribution and Effects of Chronic Ethanol Intake in the Micropig

Reduced Folate Carrier: Tissue Distribution and Effects of Chronic Ethanol Intake in the Micropig

Folate deficiency is common in alcoholic patients, in part due to abnormal transport across membranes relevant to folate homeostasis. The reduced folate carrier (RFC) transports monoglutamyl folates across tissue membranes and could be affected by chronic exposure to ethanol. The micropig model is suitable to study the effect of alcoholism on RFC and folate transport across membranes. The membrane transport of [3H]-folic acid was measured by a vacuum filtration method in jejunal brush border (JBB), liver plasma membrane (LPM), and kidney brush border (KBB) membranes vesicles from micropigs fed control or 40% ethanol diets for 12 months. RFC transcripts were analyzed by reverse transcription polymerase chain reaction in jejunal mucosa, liver, and kidney from the same animals. When we compared results from three relevant membranes in control animals, the transport of [3H]-folic acid was highest in LPM, 3-fold lower in KBB (p < 0.001), and 6-fold lower in JBB (p < 0.001). The concentration of RFC transcripts per total RNA was greatest in liver, followed by kidney and jejunum. The transport of [3H]-folic acid by JBB vesicles from chronic ethanol-fed animals exhibited 2-fold lower Km and Vmax (p < 0.05), whereas there was no ethanol effect on the Vmax of [3H]-folic acid transport by LPM or KBB. RFC transcript levels were 10-fold lower in jejunal mucosa from ethanol-fed animals than in control-fed animals (p < 0.005). Although our findings demonstrate different RFC transcript amounts and transport efficiencies among tissues, the present studies suggest that chronic ethanol exposure decreases the intestinal absorption of folic acid by altering the expression of RFC and consequently its transport kinetics in JBB. These findings provide a mechanism for the clinical finding of reduced folic acid absorption in chronic alcoholics.

Effects of Chronic Ethanol Ingestion on Nadph Oxidase Expression in the Lung In Vivo.

Effects of Chronic Ethanol Ingestion on Nadph Oxidase Expression in the Lung <i>In Vivo.</i>

K(ATP) channels mediate the beneficial effects of chronic ethanol ingestion.

Chronic ingestion of low doses of ethanol protects the myocardium from ischemic injury by activating adenosine receptors and protein kinase C. We tested the hypothesis that ATP-dependent potassium (K(ATP)) channels mediate these beneficial effects. Dogs were fed with ethanol (1.5 g/kg) or water mixed with dry food twice per day for 12 wk. After they were acutely instrumented for measurement of hemodynamics, dogs received saline (vehicle) or glyburide (0.1 mg/kg iv) and were subjected to 60 min of coronary artery occlusion followed by 3 h of reperfusion. Infarct size (through triphenyltetrazolium chloride staining) was significantly (P < 0.05) reduced to 14 +/- 1% of the left ventricular area at risk in ethanol-pretreated dogs compared with controls (25 +/- 2%). Glyburide alone did not affect infarct size (25 +/- 3%) but abolished the protective effects of ethanol pretreatment (28 +/- 3%). No differences in hemodynamics or coronary collateral blood flow (through radioactive microspheres) were observed among groups. The results indicate that K(ATP) channels mediate the protective effects of chronic consumption of ethanol.

Heart Mitochondrial Respiratory Chain Complexes Are Functionally Unaffected in Heavy Ethanol Drinkers Without Cardiomyopathy

Background: Harmful effects of chronic ethanol intake on liver mitochondria have been clearly demonstrated; however, mitochondria from skeletal muscle are preserved, and the effect of ethanol on heart mitochondria remains controversial. We assessed individual enzyme activity of mitochondrial respiratory chain (MRC) complexes and membrane oxidative damage of heart mitochondria in active ethanol drinkers before the development of dilated cardiomyopathy. Patients and Methods: Heart samples were obtained from otherwise healthy organ donor individuals with a sudden death of traumatic or neurological cause in whom hearts could not be used because of absence of matched receptors or size inadequacy. Detailed history of alcohol intake was achieved from the relatives. Citrate synthase activity was spectrophotometrically assayed, as well as absolute (nmol · min−1· mg protein−1) and relative (corrected by citrate synthase) activities of complex I, II, III, and IV of the MRC. Oxidative damage of myocardium membranes was assessed measuring the degree of lipid peroxidation by fluorescence using cis-parinaric acid as probe. Results: We included 10 ethanol drinkers (age 53 ± 13 years, 100% males, mean lifetime intake of 15.6 ± 7.9 kg ethanol · kg body weight−1) and 12 controls (age 60 ± 10 years, 75% males). Mitochondrial content did not differ between the two groups. Absolute enzyme activities for ethanol drinkers and controls were, respectively, 145 ± 75 and 130 ± 50 for complex I (p= NS); 399 ± 193 and 376 ± 100 for complex II (p= NS); 719 ± 288 and 714 ± 308 for complex III (p= NS); and 475 ± 139 and 570 ± 160 for complex IV (p= NS). After correcting such activities by citrate synthase activity, we failed again to demonstrate differences between ethanol drinkers and controls. Lipid peroxidation of myocardium membranes was similar in both groups. Conclusions: Chronic ethanol drinkers without cardiomyopathy exhibit normal MRC activity in the heart and do not show increased oxidative damage in myocardial membranes.

Heart Mitochondrial Respiratory Chain Complexes Are Functionally Unaffected in Heavy Ethanol Drinkers Without Cardiomyopathy

Harmful effects of chronic ethanol intake on liver mitochondria have been clearly demonstrated; however, mitochondria from skeletal muscle are preserved, and the effect of ethanol on heart mitochondria remains controversial. We assessed individual enzyme activity of mitochondrial respiratory chain (MRC) complexes and membrane oxidative damage of heart mitochondria in active ethanol drinkers before the development of dilated cardiomyopathy. Heart samples were obtained from otherwise healthy organ donor individuals with a sudden death of traumatic or neurological cause in whom hearts could not be used because of absence of matched receptors or size inadequacy. Detailed history of alcohol intake was achieved from the relatives. Citrate synthase activity was spectrophotometrically assayed, as well as absolute (nmol x min(-1) x mg protein(-1)) and relative (corrected by citrate synthase) activities of complex I, II, III, and IV of the MRC. Oxidative damage of myocardium membranes was assessed measuring the degree of lipid peroxidation by fluorescence using cis-parinaric acid as probe. We included 10 ethanol drinkers (age 53 +/- 13 years, 100% males, mean lifetime intake of 15.6 +/- 7.9 kg ethanol kg body weight(-1)) and 12 controls (age 60 +/- 10 years, 75% males). Mitochondrial content did not differ between the two groups. Absolute enzyme activities for ethanol drinkers and controls were, respectively, 145 +/- 75 and 130 +/- 50 for complex I (p = NS); 399 +/- 193 and 376 +/- 100 for complex II (p = NS); 719 +/- 288 and 714 +/- 308 for complex III (p = NS); and 475 +/- 139 and 570 +/- 160 for complex IV (p = NS). After correcting such activities by citrate synthase activity, we failed again to demonstrate differences between ethanol drinkers and controls. Lipid peroxidation of myocardium membranes was similar in both groups. Chronic ethanol drinkers without cardiomyopathy exhibit normal MRC activity in the heart and do not show increased oxidative damage in myocardial membranes.

Prenatal and postnatal exposure to ethanol induces changes in the shape of the dendritic spines from hippocampal CA1 pyramidal neurons of the rat

20%-ethanol was provided to adult female rats since a pregestational stage until weaning of the pups, and percentage proportion of thin, mushroom-shaped, stubby, or wide spines from the apical dendrite of hippocampal CA1 pyramidal cells, was counted at 15, 21, 40, and 90 days of age. By-kind-of-spine analysis revealed higher fluctuation of experimental spines, and less percentage of thin spines was observed in the ethanol-intoxicated rats concomitantly with a higher proportion of stubby or wide spines; through development. Because thin spines may propagate the synaptic potentials more efficiently than stubby or wide spines, this findings suggest that the electrical excitability and thereafter the firing pattern of those cells may be altered, due to the toxic effects of chronic ethanol ingestion.

Content of liver and brain ubiquinol-9 and ubiquinol-10 after chronic ethanol intake in rats subjected to two levels of dietary α-tocopherol

To assess the effect of chronic ethanol ingestion in the content of the reduced forms of coenzymes Q9 (ubiquinol-9) and Q10 (ubiquinol-10) as a factor contributing to oxidative stress in liver and brain, male Wistar rats were fed ad libitum a basal diet containing either 10 or 2.5 mg α-tocopherol/100 g diet (controls), or the same basal diet plus a 32% ethanol-25% sucrose solution. After three months treatment, ethanol chronically-treated rats showed identical growth rates to the isocalorically pair-fed controls, irrespectively of α-tocopherol dietary level. Lowering dietary α-tocopherol led to a decreased content of this vitamin in the liver and brain of control rats, without changes in that of ubiquinol-9, and increased levels of hepatic ubiquinol-10 and total glutathione (tGSH), accompanied by a decrease in brain tGSH. At the two levels of dietary α-tocopherol, ethanol treatment significantly decreased the content of hepatic α-tocopherol and ubiquinols 9 and 10. This effect was significantly greater at 10 mg α-tocopherol/100 g diet than at 2.5, whereas those of tGSH were significantly elevated by 43% and 9%, respectively. Chronic ethanol intake did not alter the content of brain α-tocopherol and tGSH, whereas those of ubiquinol-9 were significantly lowered by 20% and 14% in rats subjected to 10 and 2.5 mg α-tocopherol/100 g diet, respectively. It is concluded that chronic ethanol intake at two levels of dietary α-tocopherol induces a depletion of hepatic α-tocopherol and ubiquinols 9 and 10, thus contributing to ethanol-induced oxidative stress in the liver tissue. This effect of ethanol is dependent upon the dietary level of α-tocopherol, involves a compensatory enhancement in hepatic tGSH availability, and is not observed in the brain tissue, probably due to its limited capacity for ethanol biotransformation and glutathione synthesis.

Effects of chronic ethanol ingestion on dopamine and serotonin metabolism in the rat brain

Effects of chronic ethanol ingestion on dopamine and serotonin metabolism in the rat brain

Effect of ethanol and high-fat feeding on hepatic gamma-glutamylcysteine synthetase subunit expression in the rat.

Glutathione (GSH) is important in antioxidant defense. A major determinant of the rate of GSH synthesis is the activity of the rate-limiting enzyme, gamma-glutamylcysteine synthetase (GCS). A heavy (HS) and light subunit (LS) make up GCS; oxidative stress regulates both transcriptionally. Cis-acting elements important for the oxidative stress-induced transcriptional up-regulation of both subunits are antioxidant response element (ARE) and activator protein-1 (AP-1). Nuclear factor-kappaB (NF-kappaB) may also regulate the heavy subunit. Chronic ethanol ingestion causes oxidative stress, increases AP-1 expression, and depletes hepatic GSH. Data conflict regarding GSH synthesis and are lacking regarding GCS subunit gene expression. We examined the effect of chronic ethanol ingestion on ARE, AP-1, and NF-kappaB activity and GCS subunit expression. Male Wistar rats were fed an ethanol and high-fat (28.7% cal) diet intragastrically for 9 weeks. Liver GSH level fell by 40%, although GCS activity doubled. GCS-HS mRNA level doubled, whereas GCS-LS mRNA level remained unchanged. Electrophoretic mobility shift assay (EMSA) showed that binding to ARE, AP-1, and NF-kappaB probes all increased. In conclusion, chronic ethanol ingestion increased GCS-HS expression and GCS activity by activating cis-acting elements important for transcriptional up-regulation of GCS-HS. GCS-LS mRNA level remained unchanged despite activation of ARE and AP-1, suggesting that negative transcriptional factors may be involved or the mRNA may be unstable. Despite induction in GCS activity, GSH level fell because of alterations in the other factors important in determining the steady-state GSH level.

Effect of Chronic Ethanol Ingestion on Biochemical Circadian Rhythms in Wistar Rats

Chronic ingestion of ethanol for 60 days was known to alter the characteristics of biochemical circadian rhythms in Wistar rats. Peak times of glucose, potassium and lactic acid rhythms were delayed by 18 h, 3 h, and 3 h respectively, whereas peak times of cholesterol and malondialdehyde rhythms were advanced by 3 h and 9 h respectively during ethanol treatment. Significant changes in range ( p < 0.001 expect in calcium) and 24 h mean ( p < 0.001) of all the biochemical circadian rhythms studied were observed during ethanol treatment. The alterations in the characteristics of these biochemical circadian rhythms could be principally due to the alterations on the hepatic cellular architecture; other plausible underlying reasons are also discussed.

Effect of Chronic Ethanol Consumption on Fatty Acid Profile of Heart Tissue in Rats

The effect of chronic ethanol ingestion on fatty acid composition and lipid content of heart tissue in rats, and whether this effect depends on age, was studied. Rats were maintained on a 30% ethanol solution in drinking water for 3 and 5 months. Control animals were given water. Phospholipid concentration was unchanged in the ethanol-fed groups, compared with control groups, whereas total cholesterol content was increased at 5 months of treatment. An increase in stearic acid, palmitoleic acid, and 22:5n6 were observed at 3 months of ethanol ingestion. When ethanol was administered for 5 months, polyunsaturated fatty acids series n3 were decreased with respect to control. The effect of age on the profile of fatty acids of heart showed an increase of monounsaturated fatty acids and a decrease of long-chain polyunsaturated fatty acids in both control and ethanol-fed rats. The effect of ethanol ingestion on fatty acid composition of heart tissue is not very pronounced, but the small changes observed could contribute to the development of functional and electrophysiological features of alcoholic heart disease.

Chronic ethanol consumption induces hypomotility in the portal vein of Sardinian alcohol-preferring rats.

In order to study the physiopathological effects of chronic ethanol intake on the smooth muscle of the vascular system, we have assessed the length-tension relationship in isolated portal veins of Sardinian alcohol-preferring (sP) rats. Significant differences in motor performance were found between sP naive and sP rats exposed to ethanol consumption (12% w/v) for 48 weeks. Isolated portal veins of sP rats which consumed ethanol chronically showed a marked decrease of spontaneous and KCl-induced contraction waves when compared to sP naive rats. At optimum length (140% Lr) for maximal contractile performance, the mean amplitude wave in the portal veins of sP drinker rats was about five times less than in sP naive veins. Furthermore, in the veins of sP drinkers, the active curve showed lower values of tension at each elongation of the vascular segment, the maximum value of active tension (7.32 +/- 0.54 mN) represented a reduction in amplitude of about 32% with respect to sP naive veins. These results indicate that long-term ethanol consumption impairs portal vein motility.