[The biological mechanisms underlying alcohol dependence].

Recent advances in neuroscience have enabled alcohol dependence to be investigated at cellular and molecular levels. Alcohol exerts biological effects by interacting with cell membranes and receptors, and modifies the function of proteins which regulate signal transduction, intracellular pathways, and gene expression. Adaptation to the acute effects of alcohol constitutes a major determinant of the development of increased tolerance, withdrawal syndrome and dependence. Important targets for alcohol include transmitter-regulated ion channels, receptors coupled to guanosine triphosphate-binding proteins, second messengers, and gene transcription factors. Studies of rodents bred for alcohol sensitivity or resistance have uncovered molecules of importance for the development of alcohol dependence, and certain ethanol-sensitive genes have been identified.