Protein turnover in brain during the development of alcohol dependence

Oxidative stress is the primary event: Effects of ethanol consumption in brain

Damaging effects of reactive oxygen species on living systems are well documented. They include oxidative attack on vital cell constituents. Chronic ethanol administration is able to induce an oxidative stress in the central nervous system. In the present study, 16-18 week-old male albino rats of Wistar strain were exposed to different concentration of ethanol for 4 weeks. This exposure showed profound effect on body weight. Ascorbic acid level; and activities of alkaline phosphatase and aspartate transaminase in the brain are dependent on the concentration of ethanol exposure. Chronic ethanol ingestion elicits statistically significant increase in thiobarbituric acid reactive substances level and decrease in gluatathione level in the brain. It reduces superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities in a dose dependent manner. However, histological examination could not reveal any pathophysiological changes. Therefore, we conclude that biochemical alterations and oxidative stress related parameters respond early in alcoholism than the histopathological changes in brain.

Role of ethanol on aluminum induced biochemical changes on rat brain

Aluminum and alcohol, both are well-accepted neurotoxin. The plausible mechanisms for their neurotoxicity are also common. Therefore, the effect of ethanol on aluminum induced biochemical changes in rat brain is being studied. In the present study, ethanol exposure significantly affected the aluminum and protein content of brain. The activities of acid phosphatase and alkaline phosphatase were also changed. Aluminum exposure, on the other hand, contributed significantly in the alterations of aluminum content, acid phosphatase acivity and aspartate aminotransferase activity. Though ethanol co-exposure significantly influenced the aluminum load of brain, the interactions of these two neurotoxins were found to be significant only in case of acid phosphatase activity of brain. Therefore, it can be suggested that general neurotoxicity produced by aluminum is not modified by ethanol. However, the aluminum load caused by aluminum exposure, may be influenced by ethanol co-exposure.

Impact of Coexposure to Aluminum and Ethanol on Phosphoesterases and Transaminases of Rat Cerebrum

Ubiquitous presence along with uncontrolled use of aluminum and increasing trends of ethanol consumption in India increased the chance of coexposure to aluminum and ethanol. Possibilities are there, that both of them follow common mechanisms to produce neurotoxicity. The phosphomonoesterases and glutamate transaminases are studied in rat brain cerebrum after combined exposure to aluminum and varied doses of ethanol for 4 weeks. Dose dependent decreases in growth have been observed. The impact of aluminum on cerebral acidic and alkaline phosphomonoesterases activities were shown to be altered in a dose dependent fashion by the coexposure to ethanol. Aspartate aminotransferase and alanine aminotransferase of the cerebrum were responding differentially to aluminum exposure in the presence of different doses of ethanol exposure. It has been suggested that the ethanol-induced augmentation of impacts of aluminum on the cerebrum is dose dependent and there might be a critical level of ethanol exposure for the observed effect on cerebrum.

Possible central adenosinergic modulation of ethanol-induced alterations in [14C]glucose utilization in mice

The possible role of brain adenosine in acute ethanol-induced alteration in glucose utilization in the whole brain, as well as in the specific brain areas (cerebellum and brain stem), was investigated. Mice were killed 20-min postethanol, and the fresh tissue slices (300 microns) of brain and/or specific brain areas were incubated for 100 min in a 5.5 mM glucose medium in Warburg flasks using [6-(14)C]glucose as a tracer. Trapped 14CO2 was counted to estimate glucose utilization. Ethanol (2 g/kg, i.p.) markedly increased the glucose utilization in whole brain and in both motor areas of brain. Theophylline (50 mg/kg, i.p.), an adenosine antagonist, significantly reduced ethanol-induced increase in glucose utilization in whole brain, as well as in brain areas. However, adenosine agonist N6-cyclohexyladenosine (CHA; 0.1 mg/kg, i.p.) on the contrary, significantly accentuated ethanol-induced increase in glucose utilization in these tissues that was nearly completely blocked by theophylline pretreatment. Theophylline alone did not produce any significant change in glucose utilization, whereas CHA alone (in vivo and in vitro) significantly increased glucose utilization, as well as ethanol-induced increase in glucose utilization in an additive manner. Relevant supportive data were obtained by experiments in which adenosine deaminase (ADA), p-sulfophenyltheophylline (8-SPT), and CHA were administered in vitro to the slice preparations. Both ADA and 8-SPT were effective in almost completely blocking the ethanol-induced increase in glucose utilization, whereas CHA further enhanced the ethanol-induced increase in glucose utilization in an additive manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Ethanol inhibits C6 cell growth: fetal alcohol syndrome model

Maternal consumption of ethanol produces a pattern of malformations, including nervous system abnormalities, in the developing fetus, a state called Fetal Alcohol Syndrome. We report the dose-dependent inhibition by ethanol of the growth of a glioma derived cell line, C6 cells; the effects occur at ethanol concentrations commonly encountered in the blood during human intoxication. The effects occur with different morphological subtypes of the cell line and do not occur when the cells are exposed to iso-osmolar concentrations of other chemicals. The results demonstrate that C6 cells are a model for the study of the effects of ethanol on nervous system cell growth.

Chronic consumption of ethanol increases glucose oxidation in isolated cerebral tissue of rat

Tolerance to ethanol was induced in male Wistar rats by adding 15% ethanol to the drinking water for 3 and 9 months. The oxidation of [U-14C]glucose was measured in cerebral cortex prisms. 14CO2 production in prisms for ethanol-treated animals was markedly increased when compared to controls. Neither a single injection of a low dose of ethanol nor a comparable concentration of ethanol in vitro had this stimulatory effect.

Protein turnover in subcellular fractions of brain from the ethanol-fed rat

The effect of ethanol consumption (27% of energy intake) for 21 days, on protein synthesis and degradation in subcellular fractions of rat brain was investigated using the Na2(14)CO3 labelling procedure. Ethanol administration elicited an increase in the rate of protein synthesis in all fractions which was accompanied by an increase of similar magnitude in the rate of breakdown. These results imply that whilst ethanol increases the rate of protein turnover it is without effect on the rate of protein accretion.

Brain shrinkage in chronic alcoholics: a pathological study

A quantitative neuropathological necropsy study of 22 control and 22 chronic alcoholic subjects showed a statistically significant loss of brain tissue in the chronic alcoholic group. The loss of tissue appeared to be from the white matter of the cerebral hemispheres rather than the cerebral cortex. This may reflect a primary alteration in the composition or structure of the white matter or it may be secondary to loss of nerve cells from the cortex with subsequent degeneration of the axons in the white matter. Further morphometric analyses including cortical neuronal counts will be necessary to clarify this issue.

Ethanol and brain protein synthesis in the rat in vivo

The effect of ethanol consumption (27% of calories) for 21 days, concomitant with a low-protein (6% calories) or a normal protein diet (17.5% calories), on tyrosine kinetics and protein synthesis in the brain, was investigated. Ethanol consumption did not affect tyrosine concentrations in the plasma, cerebellum, forebrain or olfactory bulb but increased significantly the rate of synthesis of total mixed protein in the forebrain and cerebellum. This effect was observed in rats fed on both dietary protein regimes.

Natural loss of Purkinje cells during development and increased loss with alcohol

In untreated rats, degenerating Purkinje cells (P cells) were present from the 20th day of embryonic life (E20) to post-natal day 14 (PN14), but none was present on E17 or PN15. Ethanol increased the loss of P cells both before birth and up to PN6 or 8, but from PN10 no increased loss was seen. Most degenerating P cells were located below the P cell line. On PN3 ethanol killed some P cells in 12 h, and the first ultrastructural change was a dilatation of the nuclear double membrane after 8 h. Among the surviving P cells, natural cell death continued. Pentothal anesthesia on PN3 did not damage P cells. Exposure to ethanol from E12 to PN5 resulted in a large loss of P cells and retarded the foliation of the cerebellum.