Effects of ethyl alcohol on phasic and tonic contractions of the proximal stomach.

The effects of ethyl alcohol (EtOH) on the contractile activities of canine gastric corpus and fundus circular muscles were studied. EtOH, 0.1 to 1%, inhibited phasic contractions of corpus muscles but enhanced tonic contractions. These effects were both concentration dependent. The same range of EtOH concentrations caused a transient rise followed by a fall in the level of tone of fundic muscles. The effects of EtOH on ACh-stimulated contractions were also studied. Phasic contractions were stimulated by ACh and inhibited by EtOH. EtOH augmented the tone responses of both corpus and fundus muscles to ACh. Experiments were also performed to test whether EtOH had specific and direct effects on these muscles. The effects of EtOH were apparently not mediated by prostaglandins or Ach and were not, at least in corpus muscles, a nonspecific result of the hyperosmolarity of EtOH solutions. The data supplement previous studies on muscles of the distal stomach where the effects of EtOH were inhibitory to phasic contractions. The finding that the proximal stomach responds to EtOH with tonic contraction may help explain some of the controversy in the literature about the effects of EtOH on gastric emptying.