EFFECT OF METOCLOPRAMIDE ON GUINEA-PIG STOMACH - CRITICAL DEPENDENCE ON INTRINSIC STORES OF ACETYLCHOLINE

  • 1 January 1979
    • journal article
    • research article
    • Vol. 76  (3) , 492-496
Abstract
The hypothesis that metoclopramide enhances the contractile activity of the guinea pig antrum by increasing acetylcholine release from the postganglionic cholinergic nerve ending is investigated. Longitudinal muscle strips were stimulated repetitively (200 .mu.s pulses, 20 Hz, supramaximal current) for 2 h in the presence of hemicholinium-3 (200 .mu.M). Pretreatment in this manner produced a mean reduction of 50% in the acetylcholine content, when compared with that in repetitively stimulated control strips not incubated with hemicholinium-3. In the hemicholinium-3-treated strips the normal excitatory response to metoclopramide (60 .mu.M) was prevented. Only a small reduction in response to metoclopramide was detected in strips which were incubated with hemicholinium-3 but not stimulated repetitively, and in which there was no significant change in acetylcholine content. The stimulant effect of metoclopramide depends upon maintenance of intrinsic stores of acetylcholine.