Membrane Na+K+ATPase activity: changes using an experimental model of alcohol dependence and withdrawal

Reduced sensitivity of red blood cell (Na+,K+)-ATPase to ethanol in vitro in male alcoholic patients: relationship to clinical characteristics

We examined red blood cell (Na+,K+)-ATPase, its sensitivity to inhibition by ethanol in vitro, and its relationship to clinical characteristics and history in 41 newly admitted alcoholic patients and 14 age-matched healthy controls. Sensitivity to ethanol was significantly lower in the alcoholic patients and correlated negatively with ethanol intake. In addition, sensitivity of enzyme to ethanol was lower in patients with high agitation-anxiety ratings and correlated negatively with agitation and anxiety scores on the Brief Psychiatric Rating Scale. There were no relationships between (Na+,K+)-ATPase measures and depressive symptoms, history of treatment for depression, or family history of depression. These data suggest that tolerance to the effects of ethanol on (Na+,K+)-ATPase occurs in man and may be related to the severity of ethanol dependence or withdrawal.

Brain synaptosomal (Na+ and K+)ATPase activity as an index of tolerance to ethanol

Variations of brain synaptosomal (Na+ and K+)ATPase activity and development of functional tolerance to ethanol were followed simultaneously throughout a chronic ethanol treatment. Inhibition of the enzyme activity by ethanol added in vitro in the presence of noradrenaline was also assayed. Adult male rats were rendered tolerant to ethanol by daily intragastric administration of doses of 3-6 g of ethanol/kg body wt. As assessed by the hypothermic effect and impairment of motor performance on a tilting plane after injection of a challenge dose of ethanol (3 g/kg body wt. IP), functional tolerance developed slowly, was demonstrable after 2 weeks of treatment and increased for up to 4 weeks. The two tolerance tests gave parallel and positively correlated results. Concurrently with the development of tolerance, the basal activity of brain synaptosomal (Na+ and K+)ATPase increased (7% to 18%) in preparations from ethanol treated animals when compared to those from starch-fed caloric controls, and there was less inhibition of the enzyme by ethanol added in vitro in the presence of noradrenaline. The time course of the appearance of these changes in enzyme activity were positively correlated with that of behavioral tolerance, strengthening a relationship between the phenomena events. The intensity of the noradrenaline-ethanol interaction with the membrane-bound (Na+ and K+)ATPase activity could be an index of the degree of tolerance to ethanol.

Alterations in brain lipid composition of mice made physically dependent to ethanol

The ability of chronic ethanol treatment to alter CNS membrane lipids was tested. Adult C57/BL6 mice were given a liquid diet containing ethanol for eight days. This regimen produced strong physical dependence as judged by withdrawal seizures, tremors and concomitant hypothermia. Analyses were performed on cholesterol, total phospholipid content and total phospholipid acyl composition of myelin, crude (P2), light and heavy synaptosomes as well as synaptosomal plasma membranes. Chronic ethanol treatment had no effect on total phospholipid levels nor phospholipid acyl composition in any of the above subcellular fractions. In ethanol dependent mice, significant increases in cholesterol content and cholesterol/phospholipid ratios were observed in synaptosomal plasma membranes.