Anesthesia Pharmacology: Gastrointestinal Drugs
Parietal cells: found in mucosal glands of the body and fundus of the stomach.
Gastrin-most potent stimulant
Activation of postganglionic vagal fibers (muscarinic cholinergic parietal cells receptor activation)
Gastric mucosa contains large amounts of histamine in:
Mast cell cytoplasmic granules
Enterochromaffin-like cells (ECL)
H2 receptor antagonists competitively inhibit histamine action on H2 receptors, located on:
Gastric parietal cells
Cardiac atrial cells
Uterine smooth muscle cells
H2 receptor antagonists (cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid), nizatidine (Axid)) inhibit:
Basal acid secretion
Secretion in response to feeding, gastrin, histamine, hypoglycemia, or vagal stimulation
Histamine is the most important gastric acid secretion stimulant and is released from enterochromaffin-like cells by gastric and cholinergic activity
Histamine-- stimulation gastric acid secretion
Gastrin-- stimulation gastric acid secretion
Acetylcholine-- stimulation gastric acid secretion
Prostaglandins --inhibition of gastric acid secretion
Somatostatin -- inhibition of 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.
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