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A lower esophageal sphincter reflex involving substance P
The American Journal of Physiology
|April 1, 1984
Summary
Distal esophageal acidification increases lower esophageal sphincter (LES) pressure via a neural reflex involving substance P. This mechanism was identified using pharmacological agents in anesthetized cats.
Area of Science:
- Gastroenterology
- Neurogastroenterology
- Pharmacology
Background:
- The lower esophageal sphincter (LES) plays a crucial role in preventing gastroesophageal reflux.
- Understanding the neural mechanisms regulating LES pressure is vital for treating related disorders.
Purpose of the Study:
- To elucidate the mechanism by which distal esophageal acidification elevates lower esophageal sphincter (LES) pressure in anesthetized cats.
Main Methods:
- Recording intraluminal pressures and myoelectric activity using manometric catheters and electrodes.
- Administering pharmacological agents including tetrodotoxin, ethyl aminobenzoate, and substance P antagonists.
- Performing bilateral cervical vagotomy and administering various receptor antagonists.
Main Results:
- Distal esophageal acidification significantly increased LES pressure and spike activity compared to saline.
- These responses were abolished by tetrodotoxin or ethyl aminobenzoate, but not by vagotomy or other receptor antagonists.
- Tachyphylaxis to substance P abolished responses to both exogenous substance P and acid stimulation.
- [D-Pro2,D-Trp7,9]substance P partially antagonized the acid-induced LES pressure response.
Conclusions:
- Esophageal acidification triggers an enteric neural reflex to increase LES pressure.
- Substance P acts as a key neurotransmitter in this reflex pathway.
- The reflex involves spike-associated activity and is tetrodotoxin-sensitive.