Dose‐related effects of motilin on proximal gastrointestinal motility

Abstract

Aim: To assess non‐invasively the dose–response relations for the effects of exogenous motilin on antrum contraction frequency, gall‐bladder volume and gastric myoelectrical activity. Methods: In a double‐blind, randomized, placebo‐controlled, five‐way crossover study, 10 fasted healthy volunteers were infused intravenously with synthetic human motilin (0.5, 1, 2 and 4 pmol.min/kg) or placebo for 60 min. Gall‐bladder volume and antrum contractions were assessed by ultrasonography and gastric myoelectrical activity by electrogastrography. Motilin concentrations were measured using a radioimmunoassay. Results: Baseline plasma motilin levels (60 pmol/L) were similar for all treatments. Motilin levels increased upon the start of infusion and rapidly returned to baseline after cessation of the infusion. At motilin doses of 2 and 4 pmol.min/kg, the antrum contraction frequency was significantly augmented, with maximum differences of two contractions per 2‐min interval compared to placebo, while no changes in gastric myoelectrical activity were observed. Changes in gall‐bladder volume were not significantly different for any of the motilin doses compared to placebo. Conclusions: Motilin increased antrum contraction frequency, whereas no effect on gastric myoelectrical activity was observed. Antrum contraction frequency appears to be a useful biomarker for motilin efficacy, and motilin doses of 2 and 4 pmol.min/kg were equally effective.

Motilin receptor expression in smooth muscle, myenteric plexus, and mucosa of human inflamed and noninflamed intestine

“…Studies with intravenous infusion of motilin in humans showed that motilin induces increased antrum contraction frequency. 2,3 Motilin receptor location studies to obtain more information about possible functions of motilin are mainly performed in animals. These studies showed some interspecies differences.…”

Physiology of gut hormones: an overview

“…The motilin gene and the motilin receptor are also expressed in various regions of the brain [34]. Motilin does not have effects similar to ghrelin on gastric motility [35], although it does increase the frequency of antral contractions and gallbladder emptying and is a trigger factor for the migrating motor complex of the small intestine [36]. Motilin is secreted in a clear episodic pattern during fasting or during the interdigestive phase, but feeding promptly stops this secretory pattern, and plasma concentrations of motilin decrease.…”

The effect of drugs and stimulants on gastric myoelectrical activity

“…Motilin administered by intravenous infusion, despite the stimulating motility effect on the gastric antrum, did not elicit perceptible changes in the EGG record of GMA in healthy volunteers [21]. Intravenous infusion of cholecystokinin octapeptide (CCK-8) resulted in a decrease dominant power of gastric slow waves in the postprandial period, without changing their dominant frequency [22].…”