Plasma Motilin Variation During the Interdigestive and Digestive States in Man

Abstract

To evaluate the role of motilin in human physiology, we measured plasma motilin during the inter digestive and digestive states while recording antroduodenal contractile activity. In 24 healthy fasting subjects, 51 migrating periods of phase III activity were recognized, 42 of them started from the antral region and nine from the duodenum. A definite association was noted between circulating motilin and the gastric migrating motor complex. Significant peak elevations in plasma motilin were associated with phase Ills initiated from the antrum, but not with those originating from the duodenum. Exogenous synthetic motilin, when administered in supraphysiologic amounts, induced premature periods of front activity in fasting subjects. A test meal administered 30 minutes after a front of antral activity induced a significant release of motilin. Elevated plasma motilin levels were detected postprandially for a period of 30 minutes. Postprandial motilin increases were comparable in amplitude to the cyclic peak increases observed during the fasting period. Our study brings support for the argument that the contractile activity of the fasting stomach is regulated by circulating motilin in man, as it is in animals. The documented postprandial release of motilin is, however, unique to man and suggests that motilin could also be active during the digestive period in this species.

Endogenous motilin, but not ghrelin plasma levels fluctuate in accordance with gastric phase III activity of the migrating motor complex in man

“…Our data, together with previous data, report an increase in motilin plasma levels prior to gastric phase III contractions, which questions the hypothesis that the strong antral contractions during phase III induce the release of motilin . Further evidence for this causality was given by Tack et al .…”

“…The high motilin levels may decrease motilin receptor sensitivity. In fact, a refractory period for gastric stimulation by motilin has been suggested previously . Indeed, after a gastric phase III the MMC cycle duration in the gastroduodenal region is prolonged …”

“…8 The gastrointestinal hormone moti-lin seems to be an important determinant of the occurrence and origin of phase III contractions in man: a peak of plasma motilin level is present before a gastric, but not a duodenal phase III. 28,29 Further exogenous administration of motilin, or the motilin receptor agonist erythromycin, induces premature phase III contractions with a gastric origin, thereby confirming the role of the motilin receptor in the induction of gastric phase III activity. 10,30,31 Ghrelin has been implicated in the control of the MMC in animals, but its role in the control of the MMC in man is unknown.…”

The motilin receptor agonist erythromycin stimulates hunger and food intake through a cholinergic pathway

“…Indeed, in humans, only phase III contractions with a gastric but not a small-intestinal origin are preceded by a motilin plasma peak (6,7). In addition, administering exogenous motilin to dogs and humans induces gastric phase III contractions (8,9).…”

Mechanism of motilin-mediated inhibition on voltage-dependent potassium currents in hippocampal neurons

“…Motilin can be detected periodically during the interdigestive period, and can initiate the interdigestive migrating motor complex (Tack, 1992). The peripheral motilin mainly acts as the stimulatory factor for gastrointestinal motility and biliary contraction, while the intra-arterial injection of motilin can induce an antral contraction phase in a physiological dose-dependent manner (Boivin et al, 1990). It is previously reported that the motilin mRNA is expressed in the CNS of monkeys, dogs, cats, rabbits, rats and other animals (Xu et al, 2003).…”