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The apical surface of canine chief cell monolayers resists H+ back-diffusion
Nature
|January 3, 1985
Summary
Canine chief cells form a robust barrier against acid, significantly resisting hydrogen ion (H+) back-diffusion. This gastric mucosal defense mechanism is crucial for preventing acid-peptic injury.
Area of Science:
- Gastroenterology
- Cell Biology
- Physiology
Background:
- Gastric mucosa resistance to acid injury is key.
- The precise nature of the gastric 'acid barrier' is undefined.
- Chief cells are vital for gastric function.
Purpose of the Study:
- To investigate the acid-barrier function of canine fundic chief cell monolayers.
- To understand the role of chief cells in resisting H+ back-diffusion.
Main Methods:
- Ussing chamber experiments on dispersed canine fundic chief cell monolayers.
- Measurement of transepithelial resistance (R), potential difference (V), and short-circuit current (Isc).
- Exposure to varying apical and basolateral pH, aspirin, and ouabain.
Main Results:
- Apical acidification (pH 2) increased R 2.6-fold, maintaining a 1:100,000 H+ gradient for over 4 hours.
- Aspirin or basolateral acidification (pH < 5.5) rapidly decreased R.
- Ouabain-treated monolayers showed increased R but near-zero V and Isc, indicating H+ impermeability, which was lost upon apical disruption.
Conclusions:
- The apical surface of chief cells acts as a highly effective barrier to H+ diffusion.
- This chief cell barrier is a significant factor in gastric mucosal resistance to acid-peptic injury.