Pathogenesis of Peptic Ulcer Disease and Gastritis: Importance of Aggressive and Cytoprotective Factors

Abstract

Acid production is a major gastric function. Second messengers (cyclic AMP and calcium) are released when parietal cell membrane receptors (H₂, muscarinic and gastrin) are stimulated. The second messengers then stimulate the ‘gastric proton pump’ to produce hydrogen ions. New evidence suggests that there is a unidirectional flux of hydrogen ions into the lumen induced by unique physical properties of mucus and a sodium gradient from lumen to serosa. Luminal hydrogen ions, bile salts, ingested drugs, and ingested alcohol are potential gastric epithelial toxins. The stomach's protective mechanism includes a well-defined mucus layer, an epithelial bicarbonate secretion, a tight epithelium, and a good nutrient blood supply. Endogenous prostaglandins partly control these mechanisms. Modern therapeutics are increasingly directed towards improving gastric cytoprotection.

Key Words:

• Acid secretion
• Cytoprotection
• gastric mucus
• gastric physiology