On the other hand, in a study of seven male rats, Milakofsky, Miller and Vogel (1989) examined for the effect of ethanol on plasma amino acids which tend to be products of stress in rats. The authors noted that the ethanol tended to change concentrations of plasma amino acids away from normal levels in nonstressed rats, whereas in stressed rats, ethanol tended to antagonize stress-induced changes. The latter finding was said to support a tension-reduction hypothesis on the effects of ethanol. Pohorecky (1991) essentially summarizes the current body of literature regarding animal studies, stress and alcoholism by noting that:
(1) The controversy on the purported beneficial effect of alcohol on the cardiovascular system persists. A number of studies have shown a J- or U-shaped relationship between alcohol ingestion and incidence of coronary heart disease. Alcohol may also influence stress-induced changes in blood pressure. Although a number of studies have demonstrated lower blood pressure in individuals ingesting less than two drinks per day compared with abstainers or heavy alcohol imbibers, the evidence is not conclusive.
(2) It is not clear whether the interaction of alcohol and stress involves alterations in plasma catecholamines.
While, as just noted, animal studies may remain inconsistent (possibly because of the complexity of the bio-neurological response to alcoholis