Capsaicin-sensitive nerves mediate esophageal mucosal protection

Area of Science:

• Gastroenterology
• Neuroscience
• Physiology

Background:

• The esophageal mucosa faces constant threats from ingested substances and reflux.
• Prolonged exposure to damaging agents like acid, bile, or ethanol causes esophageal injury and reduced blood flow.
• Capsaicin-sensitive nerves are known to influence esophageal blood flow.

Purpose of the Study:

• To investigate if capsaicin, a probe for visceral afferent nerves, can protect the esophageal mucosa.
• To determine if capsaicin preserves mucosal blood flow during exposure to damaging agents.
• To test the hypothesis that capsaicin-sensitive nerves mediate esophageal mucosal protection.

Main Methods:

• An in vivo rabbit model of esophagitis was used.
• Rabbits received luminal instillation of 50% ethanol, with or without 1% capsaicin.
• Esophageal mucosal blood flow was measured using microspheres at baseline, 2 minutes, and 10 minutes.

Main Results:

• Ethanol exposure alone led to severe mucosal injury and near-complete loss of blood flow.
• Concurrent administration of capsaicin with ethanol protected the esophageal epithelium.
• Capsaicin treatment resulted in a sixfold increase in mucosal blood flow compared to ethanol alone.

Conclusions:

• Capsaicin-sensitive nerves act as local effectors in protecting the esophageal mucosa.
• Preservation of mucosal blood flow is a key mechanism by which these nerves confer protection.
• Targeting capsaicin-sensitive pathways may offer therapeutic strategies for esophageal protection.