GLP-1 regulates gastroduodenal motility involving cholinergic pathways

Area of Science:

• Gastroenterology
• Endocrinology
• Physiology

Background:

• Glucagon-like peptide-1 (GLP-1), a gut hormone, is known to delay gastric emptying.
• Understanding the precise mechanisms of GLP-1 on gastroduodenal motility and glucose regulation is crucial.

Purpose of the Study:

• To investigate the role of GLP-1 receptor antagonism in modulating gastroduodenal motility and pancreatic hormone secretion.
• To differentiate the effects of GLP-1 on gastric accommodation versus antroduodenal motility.

Main Methods:

• A randomized, double-blind, placebo-controlled, four-arm, cross-over trial involving 10 healthy volunteers.
• Infusion of exendin(9-39) (a GLP-1 receptor antagonist), atropine, or saline during fasting and postprandial duodenal perfusion.
• Assessment of antro-pyloro-duodenal and fundic motility, gastric compliance, and plasma hormone levels (glucagon, insulin).

Main Results:

• Exendin(9-39) increased fasting and postprandial glycemia and plasma glucagon, but not insulin.
• GLP-1 receptor antagonism reduced proximal gastric accommodation and gastric compliance, effects abolished by atropine.
• Exendin(9-39) altered postprandial antral inhibition and pyloric tone, independent of cholinergic mechanisms.

Conclusions:

• GLP-1 receptor antagonism impacts gastric accommodation through cholinergic pathways.
• GLP-1 influences antroduodenal motility independently of cholinergic pathways.
• GLP-1 contributes to glucose homeostasis partly by suppressing glucagon secretion.