Medical Pharmacology Chapter 27: Gastrointestinal Drugs
Gastric acid secretion responds to anticipation of food, sight, smell, taste
Stimulation of mechanical and chemical gastric wall receptors by luminal contents.
Gastrin release (small amount); release of other peptides that stimulate gastric acid secretion
Coffee (both caffeine containing and caffeine free) stimulates gastric acid secretion by stimulating gastric release
Beer and wine: stimulation of gastric acid secretion
Intragastric pH = 3; partial inhibition
Intragastric pH < or = 1.5; complete blockade of gastrin release
Antral mucosal endocrine cells (D cells) contain somatostatin and impinge on nearby gastrin cells and parietal cells.
Somatostatin reduces gastrin release thereby reducing gastric acid secretion by:
Inhibiting parietal cells secretion
Inhibiting histamine release by enterochromaffin-like cells
Secreted gastric acid plus effects of pepsin promote tissue injury
Gastric acid promotes cleavage of pepsinogen (inactive) to proteolytically-active pepsins
Direct correlation between pepsinogen I serum concentrations and maximal gastric acid secretion.
Friedman, L. S. and Peterson, W.L. Peptic Ulcer and Related Disorders In Harrison's Principles of Internal Medicine 14th edition, (Isselbacher, K.J., and Braunwald, E., Wilson, J.D., Martin, J.B., Fauci, A.S. and Kasper, D.L., eds) McGraw-Hill, Inc (Health Professions Division), 1998, pp. 1597-1616.