A biochemical and genetic approach to alcoholism

Responses to cholinergic agonists of rats selectively bred for differential sensitivity to ethanol

Alcoholics are almost invariably heavy users of tobacco. Both alcoholism and smoking appear to be influenced by genetic factors but it is not known whether the same or different genes regulate the abuse of ethanol and nicotine. Recent studies have demonstrated that the long-sleep (LS) and short-sleep (SS) mouse lines, which were selectively bred for differences in ethanol-induced anesthesia ("sleep-time"), also differ in several effects of nicotine and the muscarinic agonist, oxotremorine. In order to determine whether or not these differences are due to chance, the relative sensitivities of rat lines which were selectively bred for differences in ethanol-induced sleep-time were determined. The high alcohol sensitivity (HAS) rat line was more sensitive to the locomotor and body temperature depressant effects of nicotine than was the low alcohol sensitivity (LAS) rat line. The control line (CAS) was intermediate in sensitivity. The rat lines did not differ in sensitivity to oxotremorine's hypothermia-producing effects. The numbers and affinities of two classes of brain nicotinic receptors were measured in eight brain regions. No differences among the rat lines were detected. These results suggest that ethanol elicits some of its depressant actions via an effect on brain nicotinic systems, but the differences in sensitivity to ethanol and nicotine are probably not due to differences in the number of brain nicotinic receptors. Perhaps this interaction explains the high correlation between alcoholism and smoking in humans.

Ethanol-nicotine interactions in long-sleep and short-sleep mice

The possibility that common genetic factors regulate initial sensitivities to ethanol and nicotine as well as the development of cross-tolerance between these agents was explored using the long-sleep (LS) and short-sleep (SS) mice. The LS mice proved to be more sensitive to an acute challenge with nicotine than were the SS mice. Segregation analysis (F1, F2, backcross) indicated that ethanol sensitivity and nicotine sensitivity segregate together. Acute pretreatment with nicotine did not significantly affect sensitivity to ethanol, but ethanol pretreatment altered nicotine responsiveness. The LS mice develop more tolerance to nicotine and ethanol than do the SS and they also develop more cross-tolerance. These genetically determined differences in initial sensitivities, and tolerance and cross-tolerance development are not readily explained by differences in brain nicotinic receptor numbers.

Transketolase abnormality in cultured fibroblasts from familial chronic alcoholic men and their male offspring

We have investigated a thiamine-dependent enzyme, transketolase, in cultured fibroblasts from 41 human subjects, including patients with alcoholism-associated Wernicke-Korsakoff syndrome (n = 3), familial chronic alcoholic males (n = 7), their sons (n = 7), nonalcoholic men (n = 7), their male offspring (n = 7), and three generations of an Amish family (n = 10) without any history of alcoholism. This study was undertaken to delineate whether transketolase abnormality (i.e., high Michaelis Menton constant (Km) for thiamine pyrophosphate), previously reported in patients with Wernicke-Korsakoff syndrome is prevalent among familial chronic alcoholic men and their sons without prior history of alcohol abuse but who are at high risk for alcoholism. Our data suggest that an inborn error (i.e., high Km of transketolase for thiamine pyrophosphate) predisposing to thiamine deficiency diseases similar to those reported in Wernicke-Korsakoff syndrome may occur in the general population. However, for some as yet unexplained reason(s) this variant seems to occur more frequently among familial chronic alcoholic men and their male offspring without any history of alcoholism. The inheritance pattern of this enzyme variant as revealed from an Amish pedigree study may be autosomal recessive as previously suggested.

A two dimensional model of alcohol consumption: possible interaction of brain catalase and aldehyde dehydrogenase

The possible existence of a biological marker system mediating voluntary consumption of ethanol in rats has been examined in a series of studies. The working hypothesis underlying this research was that acetaldehyde, the primary metabolite of ethanol, mediates the positive reinforcing properties of ethanol and thus underlies the voluntary consumption of ethanol in both animals and humans. We further hypothesized that brain catalase and aldehyde dehydrogenase, the enzymes controlling the production and elimination of acetaldehyde in the brain, may represent a biological marker system underlying the affinity of the animals to consume ethanol. Data demonstrating that the activity levels of these enzymes are positively correlated with alcohol ingestion seems to suggest that it is likely that the enzyme activity can serve as a predictor of the propensity to drink alcohol. A predictive model is proposed which describes the modulation of voluntary ethanol intake through the activity of these enzymes and their role in determining rates of formation and degradation of acetaldehyde in the brain.

Beta-adrenoceptor binding defects in cell lines from families with manic-depressive disorder

Binding of 125I-iodohydroxybenzylpindolol to beta-adrenoceptors has been examined in lymphoblastoid cell lines from members of 5 families affected by manic-depressive disorder. Cell lines from 6 manic-depressives, 7 unaffected relatives and 11 non-psychiatric controls were examined. Binding was reduced to less than half of control values in cell lines from 4 out of 6 manic-depressives and only 1 out of 18 unaffected relatives or controls. All the cell lines with reduced beta-adrenoceptor binding came from 3 families; members of the remaining 2 families showed normal binding. These findings suggest that genetic heterogeneity is present in manic-depressive disorder and that a beta-adrenoceptor defect may influence genetic susceptibility to the disorder.

Alienation, Human Transformation and Adolescent Drug Use: Toward a Reconceptualization of the Problem

Drug related dependencies and alcohol addiction have become in many ways characteristic of the American way of life. Having reached down to America's children, the rampant spread of alcoholism and drug abuse remains one of this country's most pressing unsolved problems, with many scholars recognizing that no single factor can explain its etiology or serve as the basis of its remediation.

In this article, the author reviews the conventional conceptualization of the problem and provides the basis of a reconceptualization which has the potential for explicating how seriously alcoholism may be embedded in the fundamental American cultural fabric. In this regard, it is suggested that adolescent alcoholism may be symptomatic of the crisis found in the American value base wherein there is a gap between the meaning of human being and the experience of human being which results in a self-conscious sense of alienation. The implication of this work suggest that the remediation of adolescent alcoholism requires the transformation of American culture. The author briefly suggest that an African based transformation may be what is needed.

Evidence of genetic predisposition to alcoholic cirrhosis and psychosis: twin concordances for alcoholism and its biological end points by zygosity among male veterans

Medical histories of the 15,924 male twin pairs in the National Academy of Sciences-National Research Council Twin Registry were examined to determine, within pairs, concordances for alcoholism and its medical end points. Prevalences per 1,000 among individual twin subjects were 29.6 for alcoholism, 4.1 for alcoholic psychosis, 14.2 for liver cirrhosis, and 2.1 for pancreatitis. Prevalences were similar to monozygotic (MZ) and dizygotic (DZ) twins. Prevalences in percent among co-twins of diagnosed subjects, that is case-wise twin concordance rates, were, respectively, by diagnosis: alcoholism: 26.3 (MZ), 11.9 (DZ); alcoholic psychosis: 21.1 (MZ), 6.0 (DZ); and liver cirrhosis: 14.6 (MZ), 5.4 (DZ). No twin pairs concordant for pancreatitis were found. The greater concordance for alcoholic psychosis and for liver cirrhosis among MZ than DZ twins could not be explained by the difference in alcoholism concordance between them. The difference in concordance between MZ and DZ twins persisted when, in addition, it was assumed that only half of the actually occurring cases of alcoholism and of each of the end points have been ascertained. These results provide evidence in favor of genetic predisposition to organ-specific complications of alcoholism and should serve to stimulate searches for the underlying biochemical mechanisms.

Brain and liver aldehyde dehydrogenase activity and voluntary ethanol consumption by rats: relations to strain, sex, and age

Voluntary ethanol consumption and brain and liver aldehyde dehydrogenase (ALDH) activity were measured in male and female rats of the Tryon Maze-Bright (S1), Tryon Maze-Dull (S3), and Wistar strains. The levels of brain ALDH measured in the different groups, corresponded well to the levels of ethanol consumption, while differences in liver ALDH corresponded well to only the strain differences in ethanol intake. Within individual groups, levels of ethanol consumption correlated better with levels of brain and liver aldehyde-oxidizing capacity. Age affected both voluntary ethanol intake and liver ALDH levels, but there were no systematic relations between the two effects. Age did not significantly affect the cerebral-aldehyde oxidizing capacity. It is argued that inherent variation in brain ALDH activity may be a principal biochemical counterpart of the differences in ethanol intake amoung different strains and sexes of laboratory rats.

Abnormality of a thiamine-requiring enzyme in patients with Wernicke-Korsakoff syndrome

We studied a thiamine-requiring enzyme in cultured cells from four patients with the Wernicke-Korsakoff syndrome to determine whether these patients have a genetic predilection to thiamine deficiency. Transketolase in fibroblasts from the patients with the syndrome bound thiamine pyrophosphate less avidly than control lines. The apparent Km for thiamine pyrophosphate was 195 +/- 31 micron for transketolase in extracts of the patients' cells as compared to 16 +/- 2 micron in six control lines (means +/- S.E.M.: P less than 0.001). The ranges were 146 to 281 micron for the patients and 12 to 20 micron for the controls. The abnormality in transketolase persisted through serial passages in tissue culture in cells grown in medium containing excess thiamine and no ethanol, indicating that the aberrations were genetic rather than dietary. The abnormality of transketolase in this syndrome would presumably be clinically unimportant if the diet was adequate. These patients appear to have deleterious inborn enzymatic abnormalities of a type originally postulated by Garrod.