Relationship between interdigestive gallbladder emptying, plasma motilin and migrating motor complex in man

Abstract

The aim of this study was to elucidate the importance of biliary output for the regulation of migrating motor complex and the release of plasma motilin. Gallbladder emptying was monitored by hepatobiliary scintigraphy, plasma motilin concentration by radioimmunoassay and gastrointestinal motility by a perfused catheter system. During a total recording time of 46 h and 20 min in 16 volunteers, we observed 29 episodes of gallbladder emptying, 27 plasma motilin peaks and 23 activity fronts (phase 3 activity) of the migrating motor complex (MMC). Twelve episodes of gallbladder emptying started in phase 1 and continued into phase 2 of the MMC. The remaining 17 episodes of gallbladder emptying started in phase 2, and three of these continued into phase 3 of the MMC. Biliary output was associated with a significant rise in plasma motilin concentration, whereas plasma motilin significantly decreased after the activity fronts. These observations may explain the well-known fluctuations of plasma motilin concentration in the fasted state. Motilin is released into the circulation as a result of biliary output, while the ensuing activity front of the MMC removes this stimulant from the proximal small bowel, resulting in a fall in plasma motilin. In conclusion, we have confirmed a temporal relationship between biliary output into the duodenum and the release of plasma motilin. The observed transition from phase 1 to phase 2 and from phase 2 to phase 3 of the MMC during gallbladder emptying episodes suggests that biliary output stimulates gastrointestinal motility in the fasted state.

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

“…This discrepancy has not been described so far to our knowledge. Possible factors contributing to this difference may include luminal factors such as pH or bile acids which are known to affect motilin release . The high motilin levels may decrease motilin receptor sensitivity.…”

Dose‐related effects of motilin on proximal gastrointestinal motility

“…It is well known that cyclic fluctuations in gall‐bladder volume occur during the fasted state, and that the fluctuations are related to endogenous motilin peaks during the phases of the migrating motor complex 5 , . 15 , 16 The start of the motilin/placebo infusion was unrelated to the phase of the migrating motor complex, and thus it is possible that gall‐bladder contraction during placebo infusion was triggered by endogenous motilin release. In addition, the effect of motilin on the gall‐bladder is only small.…”

Intraduodenal conjugated bile salts exert negative feedback control on gall bladder emptying in the fasting state without affecting cholecystokinin release or antroduodenal motility

“…Periodic gall bladder emptying in the fasting state is associated with phase III of the intestinal MMC, 7 8 25 possibly mediated by an increase in plasma motilin levels. [26][27][28][29] It has therefore been suggested that high levels of intraduodenal bile salts may initiate phase III activity. Nevertheless, controversial results have been reported on the relationship of phase III and gall bladder contraction in the interdigestive state.…”