The effects of the synthetic motilin on the gastric motility were investigated in the dogs with innervated antral pouches in fasting state. The results were as follows: 1) The synthetic motilin stimulated markedly the gastric motor activity in both the contraction pressure and the frequency of the peristalsis . 2) Tetragastrin produced more regular and higher frequent contractions compared with synthetic motilin, but acted to weaker the contraction pressure. 3) In simultaneous administration of

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... the synthetic motilin and the tetragastrin , the synthetic motilin acted more strongly in the contraction pressure , on the other hand tetragastrin in the frequency of the peristalsis. 4) The peristaltic contractions induced by synthetic motilin were completely abolished by the administration of the atropine sulfate . 5) Under medical vagotomy, synthetic motilin was not able to produce any peristatlic contractions, but tetragastrin stimulated strongly the gastric motility .