Ethyl alcohol (EtOH) is a commonly used and abused drug. One of the many parts of the body affected by EtOH is the gastrointestinal tract. Although some of the gastrointestinal disorders associated with alcohol use have been widely investigated, studies of its effects on gastrointestinal motility have been largely neglected. It is known that EtOH interferes with the ability of the stomach to empty, and there have been studies showing effects on small and large intestinal motility. But these studies, for the most part, have not investigated the mechanisms responsible for motor disorders. In the last grant period we investigated the direct effects of EtOH on gastric muscles, and found that, at concentrations achieved in blood, EtOH reduces the force and frequency of gastric contractions. These effects appear to be due to the ability of EtOH to interfere with the electrical excitability mechanisms of the smooth muscle cells. Preliminary data shows that EtOH also affects dudodenal and colonic muscles. Mechanical and intracellular electrophysiological experiments are planned to characterize the effects of EtOH in these organs. By comparing the responses of muscles from several sites, we hope to develop a general theory of the electrical and mechanical effects of EtOH in GI smooth muscles. Mechanistic studies are also planned to test the hypothesis that EtOH alters these parameters by altering the conductance of specific ionic channels in the cell membranes of smooth muscles.