The control mechanisms of gastric emptying are not overridden by motor stimulants

Abstract

We wanted to determine if an acceleration of the normal emptying rate by motor stimulants interfers with control mechanisms limiting gastric emptying. Therefore, we studied the effects of 5-hydroxytryptophane (5-HTP) and cisapride on canine gastrointestinal motility and gastric emptying after ingestion of viscous acaloric and nutritive meals. Prolonged contractions and relaxations that change lumen size (isotonic component) and wall tension (isometric component) are defined as "basal contractions" and "basal relaxations", respectively. The nutrient meal emptied much slower than the acaloric meal due to several alterations of gastric, pyloric, and duodenal motility. Both drugs stimulated antral motility but failed to accelerate gastric emptying of the nutrient meal. The main causes for the failure were a basal relaxation of the proximal antrum and a basal contraction of the duodenum. In conclusion, basal contractions of the proximal antrum and duodenum play an important role in the process of gastric emptying, and under physiological conditions the control mechanisms of gastric emptying provide an optimal emptying rate that cannot be markedly accelerated by 5-HTP and cisapride.

VB20B7, a Novel 5-HT-ergic Agent with Gastrokinetic Activity. II. Evaluation of the Gastroprokinetic Activity in Rats and Dogs

“…Prokinetic drugs like cisapride clearly stimulate gastric and intestinal contractions in dogs and normal healthy subjects, but gastric emptying may not be enhanced (Wulschke et al 1986;Edwards et a1 1987). It was therefore of interest to induce gastroparesis pharmacologically in rats and in dogs (Muller-Lissner et a1 1986;Gullikson et al 1991b) in order to demonstrate clearly the effects of prokinetic benzamides on gastric emptying.…”

5‐Hydroxytryptamine‐Mediated Responses in Myenteric Neurons of the Guinea Pig Gastric Corpus: Effect of ICS 205–930 and Cisapride

“…The protocol for measuring gastric emptying, especially in healthy animals, is crucial for the interpretation of the results. In a recent study it was shown that prokinetic drugs, even though they markedly stimulate gastric motility, are not able to enhance gastric emptying of a nutrient meal in conscious healthy dogs (28). However, they could accelerate gastric emptying of an acaloric meal in the same dogs, indicating that changes in the composition and volume of a test meal led to different results (28,291.…”

“…In a recent study it was shown that prokinetic drugs, even though they markedly stimulate gastric motility, are not able to enhance gastric emptying of a nutrient meal in conscious healthy dogs (28). However, they could accelerate gastric emptying of an acaloric meal in the same dogs, indicating that changes in the composition and volume of a test meal led to different results (28,291. ICS 205-930 increased the contractility of gastric smooth muscle strips and accelerated gastric emptying in guinea pigs (14).…”

Quantification of gastric emptying caused by impaired coordination of pyloric closure with antral contraction: a simulation study

“…Gastric mixing and emptying are modulated by gastric motor functions, including the peristaltic and tonic contractions of the stomach and opening and closure of the pylorus. A number of studies have been conducted to investigate the relationship between gastroduodenal motility and the emptying of gastric contents [1][2][3][4][5][6]. Closure of the pylorus is coordinated with antral contractions [7,8].…”