Electrical basis for the effects of ethyl alcohol on canine gastric corpus muscles

The effects of ethyl alcohol (EtOH) on membrane potential and slow wave activity were tested in strips of canine corpus circular muscle. Previous studies have shown that EtOH (0.1-1%) reduced the force and frequency of phasic contractions of corpus muscles and increased tone. It was the intention of this study to determine whether the mechanical effects were due to an electrical mechanism. Intracellular recordings revealed that EtOH hyperpolarized resting membrane potential and reduced the amplitude, duration and frequency of slow waves. These changes were concentration-dependent over the same range of EtOH concentrations that inhibited phasic mechanism activity. Simultaneous recordings of force and membrane potential demonstrated these effects. The tone produced by corpus muscles exposed to EtOH could not be explained by an electrical mechanism. The fact that membrane potential and several parameters of the slow wave depolarization are affected by EtOH might be explained by an increase in membrane conductance produced by EtOH.