GENETICS OF ALCOHOLISM - ROLE OF THE ENDOGENOUS OPIOID SYSTEM

At the present time alcoholism is recognized as a metabolic disease ex hibiting the clinical features of craving for alcohol, loss of control over drinking, tolerance and physical dependence on alcohol, while bo th epidemiological and experimental studies have demonstrated that gen etic factors may be important in determining whether an individual has a high or low vulnerability to develop alcoholism. Evidence also indi cates that alcoholism is not characterized by a single gene single all ele inheritance. Instead it seems that multiple genes and environmenta l factors interact to increase or decrease an individual's vulnerabili ty to become an alcoholic. Current research is aimed al investigating whether certain behavioral, physiological and biochemical markers are highly associated with the incidence of alcoholism. Among the biochemi cal markers currently under investigation is the endogenous opioid sys tem and its implication in mediating the reinforcing effects of ethano l. It is the objective of this manuscript to review current research a n: (a) the interactions of ethanol with the endogenous opioid system a t the molecular level; (b) the existence of genetically determined dif ferences in the response of the endogenous opioid system to ethanol be tween subjects at high and low risk for excessive ethanol consumption, as well as between lines of animals showing preference or aversion fo r ethanol solutions; (c) the decrease of alcohol consumption following pretreatment with opioid antagonists; and (d) the possible use of spe cific opioid receptor antagonists together with behavioral therapy to modify drinking behavior, to control craving and to prevent relapse.