The role of acetaldehyde in the actions of alcohol (update 2000).
BACKGROUND
Recent advances in the field of acetaldehyde (AcH) research have raised the need for a comprehensive review on the role of AcH in the actions of alcohol. This update is an attempt to summarize the available AcH research.


METHODS
The descriptive part of this article covers not only recent research but also the development of the field. Special emphasis is placed on mechanistic analyses, new hypotheses, and conclusions.


RESULTS
Elevated AcH during alcohol intoxication causes alcohol sensitivity, which involves vasodilation associated with increased skin temperature, subjective feelings of hotness and facial flushing, increased heart and respiration rate, lowered blood pressure, sensation of dry mouth or throat associated with bronchoconstriction and allergy reactions, nausea and headache, and also reinforcing reactions like euphoria. These effects seem to involve catecholamine, opiate peptide, prostaglandin, histamine, and/or kinin mechanisms. The contribution of AcH to the pathological consequences of chronic alcohol intake is well established for different forms of cancer in the digestive tract and the upper airways. AcH seems to play a role in the etiology of liver cirrhosis. AcH may have a role in other pathological developments, which include brain damage, cardiomyopathy, pancreatitis, and fetal alcohol syndrome. AcH creates both unpleasant aversive reactions that protect against excessive alcohol drinking and euphoric sensations that may reinforce alcohol drinking. The protective effect of AcH may be used in future treatments that involve gene therapy with or without liver transplantation.


CONCLUSIONS
AcH plays a role in most of the actions of alcohol. The individual variability in these AcH-mediated actions will depend on the genetic polymorphism, not only for the alcohol and AcH-metabolizing enzymes but also for the target sites for AcH actions. The subtle balance between aversive and reinforcing, protecting and promoting factors will determine the overall behavioral and pathological developments.
Eriksson
C J
CJ
Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland. peter.eriksson@ktl.fi
D000079:Acetaldehyde / Q000378:metabolism*; D000426:Alcohol Dehydrogenase / Q000235:genetics / Q000378:metabolism; D000428:Alcohol Drinking / Q000378:metabolism* / Q000503:physiopathology; D020751:Alcohol-Induced Disorders / Q000235:genetics / Q000378:metabolism*; D000435:Alcoholic Intoxication / Q000378:metabolism / Q000503:physiopathology; D000437:Alcoholism / Q000235:genetics / Q000378:metabolism*; D000444:Aldehyde Dehydrogenase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000818:Animals; D005059:Euphoria / Q000502:physiology; D006801:Humans; D008108:Liver Diseases, Alcoholic / Q000378:metabolism; D011110:Polymorphism, Genetic / Q000235:genetics*
D000426:Alcohol Dehydrogenase; D000444:Aldehyde Dehydrogenase; D000079:Acetaldehyde