Gastric acid secretion.
The present review summarizes the past year's literature, both clinical and basic science, regarding neuroendocrine and intracellular regulation of gastric acid secretion and proper use of antisecretory medications.



Gastric acid kills microorganisms, modulates the gut microbiome, assists in digestion of protein, and facilitates absorption of iron, calcium, and vitamin B12. The main stimulants of acid secretion are gastrin, released from antral G cells; histamine, released from oxyntic enterochromaffin-like cells; and acetylcholine, released from antral and oxyntic intramural neurons. Other stimulants include ghrelin, motilin, and hydrogen sulfide. The main inhibitor of acid secretion is somatostatin, released from oxyntic and antral D cells. Glucagon-like peptide-1 also inhibits acid secretion. Proton pump inhibitors (PPIs) reduce acid secretion and, as a result, decrease somatostatin and thus stimulate gastrin secretion. Although considered well tolerated drugs, concerns have been raised this past year regarding associations between PPI use and kidney disease, dementia, and myocardial infarction; the quality of evidence, however, is very low.



Our understanding of the physiology of gastric secretion and proper use of PPIs continues to advance. Such knowledge is crucial for improved management of acid-peptic disorders.
Division of Gastroenterology, Department of Medicine, Virginia Commonwealth University Health System, Richmond and Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia, USA.
Mitchell L
ML
Schubert
D018118:Chloride Channels / Q000502:physiology; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism*; D005755:Gastrins / Q000502:physiology; D000069196:Gastrointestinal Microbiome / Q000187:drug effects; D006632:Histamine / Q000502:physiology; D006801:Humans; D009490:Neurosecretory Systems / Q000502:physiology; D015221:Potassium Channels / Q000502:physiology; D054328:Proton Pump Inhibitors / Q000009:adverse effects; D013004:Somatostatin / Q000502:physiology
D018118:Chloride Channels; D005755:Gastrins; D015221:Potassium Channels; D054328:Proton Pump Inhibitors; D013004:Somatostatin; D006632:Histamine