The relaxant responses induced by ethanol in the smooth muscle: role of extracellular and intracellular Ca2+ [Duz kasta etanol ile induklenen gevseme cevaplari: ekstraseluler ve intraseluler Ca2+'un rolu

Abstract

Since worldwide alcohol consumption, the understanding the mechanism of action of ethanol is important in the gastrointestinal tract. In this study we aimed to clarify the role of extracellular and intracellular calcium (Ca2+) on relaxations induced by ethanol in isolated mouse gastric fundus. Mice (Swiss albino) of either sex were used in this study. After killing the mice by cervical dislocation the gastric fundal strips were prepared by longitudinal incision and mounted under 0.5 g tension in an organ bath filled with Tyrode’s solution. The bath medium was maintained at 37 oC and gassed with %95O2 and 5%CO2. Experimental data were recorded by an isometric transducer. Ethanol (164 mM) caused reproducible relaxations in isolated mouse gastric fundal strips. These relaxations were significantly inhibited by verapamil (10-5-5x10-4 M), a blocker of L-type Ca2+ channels, and ruthenium red (10-5-10-4 M), a blocker of ryanodine receptors (intracellular Ca2+ channels) in a concentration dependent manner. On the other hand cyclopiasonic acid (CPA; 10-6-10-5 M), a blocker of Ca2+-ATPase, failed to affect the relaxations induced by ethanol. The results of experimental data suggest that extracellular Ca2+ influx and intracellular Ca2+ release may play a role on relaxations induced by ethanol in the isolated mouse gastric fundal smooth muscle.