EFFECTS OF ETHYL-ALCOHOL ON CANINE JEJUNAL CIRCULAR SMOOTH-MUSCLE

Ethyl alcohol has many symptomatic effects on the gastrointestinal tra ct. Our aim was to determine the effects of ethyl alcohol on circular smooth muscle contractility of the canine small bowel. Mechanical and intracellular electrical recordings were made in vitro from the circul ar muscle of full-thickness strips of muscularis externa from canine j ejunum, Ethyl alcohol (20-120 mM) dose-dependently decreased spontaneo us contractile amplitude, hyperpolarized the resting membrane potentia l, and decreased the amplitude of the slow wave, Ethyl alcohol also de creased the amplitude of the inhibitory junction potential (during ele ctrical field stimulation-EFS) but did not alter the maximum absolute cell-polarized potential reached during EFS, An increase in extracellu lar calcium (15 mM) partially restored spontaneous contractile amplitu de, resting membrane potential, and slow-wave amplitude. Ethyl alcohol decreased the amplitude of contractions evoked by acetylcholine, CCK, and substance P. These data suggest that ethyl alcohol has direct eff ects on jejunal smooth muscle contractility. These effects can be part ially reversed by increasing the availability of extracellular calcium .