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Cholinergic agents modulate transport in the isolated, perfused ileum
M K Barry1, J D Aloisi, C J Yeo
1Department of Surgery, Johns Hopkins Medical Institutions, Baltimore, Maryland 21287-4606, USA.
The Journal of Surgical Research
|December 1, 1995
Summary
Acetylcholine directly stimulates ileal secretion of water and electrolytes via muscarinic receptors. This effect on intestinal transport occurs independently of changes in blood flow or gut movement.
Area of Science:
- Gastroenterology
- Neurogastroenterology
- Physiology
Background:
- The small intestine possesses extensive cholinergic innervation influencing its function.
- Cholinergic agents are known to affect intestinal physiology, but their direct impact on transport independent of vascular and motility changes requires clarification.
Purpose of the Study:
- To investigate whether cholinergic agents modulate ileal transport independently of intestinal vascular resistance and motility.
- To determine the specific receptors involved in acetylcholine-induced ileal secretion.
Main Methods:
- Ex vivo perfusion of rabbit ileal segments with a physiologic electrolyte solution.
- Measurement of net water, sodium, and chloride fluxes.
- Infusion of acetylcholine, atropine, and hexamethonium to assess their effects on transport, perfusion pressure, and motility.
Main Results:
- Acetylcholine significantly increased the secretion of water, sodium, and chloride.
- Atropine, but not hexamethonium, blocked the prosecretory effect of acetylcholine.
- No significant changes in perfusion pressure or motility were observed with any infused agent.
Conclusions:
- Acetylcholine-mediated ileal secretion is dependent on atropine-sensitive muscarinic receptors.
- Cholinergic influence on ileal transport is direct and not mediated by systemic neural pathways.
- Acetylcholine affects ileal transport independent of alterations in vascular resistance or motility.