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. 1982 Jan;23(1):66–70. doi: 10.1136/gut.23.1.66

Effect of metoclopramide in guinea-pig ileum longitudinal muscle: evidence against dopamine-mediation.

M A Zar, O Ebong, D N Bateman
PMCID: PMC1419580  PMID: 7056499

Abstract

The investigation examines the hypothesis that metoclopramide-induced potentiation of gastrointestinal motility is mediated through dopamine receptors. In vitro studies on the longitudinal muscle of the guinea-pig ileum were performed. Metoclopramide, in concentrations comparable with those seen in plasma after therapeutic doses in man, selectively potentiated the cholinergic response Dopamine (1-100 microM) inhibited cholinergic transmission by inhibiting neuronal acetylcholine release. The inhibitory action of dopamine was antagonised by phentolamine, and alpha-adrenoceptor antagonist, but not by the dopamine receptor antagonists metoclopramide or primozide. Bromocriptine inhibited cholinergic responses by a postsynaptic mechanism which was not antagonised by metoclopramide, primozide, or phentolamine. The results are consistent with the view that metoclopramide-induced potentiation of gastrointestinal motility does not involve local dopamine receptors.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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