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Duodenal pH governs interdigestive motility in humans
1Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109.
The American Journal of Physiology
|January 1, 1995
Summary
Duodenal pH regulates the interdigestive migrating myoelectric complex (IMMC). An alkaline duodenal pH is essential for initiating gastric phase III, while acidic conditions prevent it, even with normal motilin levels.
Area of Science:
- Gastroenterology
- Physiology
Background:
- The interdigestive migrating myoelectric complex (IMMC) is a cyclical pattern of gastrointestinal motility.
- Regulation of IMMC, particularly gastric phase III, is not fully understood.
Purpose of the Study:
- To investigate the role of duodenal pH in the regulation of IMMC occurrence.
- To determine if duodenal pH influences the timing of gastric phase III.
Main Methods:
- Studied fasting gastroduodenal motility, duodenal pH, and plasma motilin in 15 healthy subjects.
- Analyzed duodenal pH fluctuations during different phases of the IMMC.
- Investigated the effect of induced low duodenal pH on gastric phase III using HCl perfusion.
Main Results:
- Duodenal pH varied significantly during different IMMC phases, being acidic during phase II and alkaline during phase III.
- Delayed gastric phase III was associated with persistently low duodenal pH (< 4) during late phase II.
- Intraduodenal HCl perfusion to lower duodenal pH prevented gastric phase III occurrence despite normal plasma motilin.
Conclusions:
- Duodenal pH is a critical regulator of IMMC regularity.
- An alkaline duodenal pH is necessary for the initiation of gastric phase III.
- Low duodenal pH inhibits gastric phase III, irrespective of normal motilin cycles.