Acid secretion by isolated primate gastric mucosa

Area of Science:

• Gastroenterology
• Pharmacology
• Physiology

Background:

• Gastric acid secretion is a complex physiological process regulated by various agonists.
• Understanding the relative potencies and interactions of these agonists is crucial for comprehending gastric function.

Purpose of the Study:

• To compare the potencies and maximal responses of pentagastrin, histamine, and acetylcholine on isolated rhesus gastric mucosa.
• To investigate the inhibitory effects of metiamide and atropine on agonist-stimulated acid secretion.

Main Methods:

• Isolated rhesus gastric mucosa was used to measure acid secretion stimulated by pentagastrin, histamine, and acetylcholine.
• The effects of metiamide and atropine on stimulated acid secretion were assessed.
• Transmucosal potential differences and resistances were monitored during stimulation and inhibition.

Main Results:

• Acid secretion potencies were pentagastrin > histamine > acetylcholine.
• Histamine elicited the greatest maximal secretory response, twice that of pentagastrin or acetylcholine.
• Metiamide surmountably inhibited histamine-induced secretion but not pentagastrin-induced secretion.
• Atropine inhibited acetylcholine response but not histamine response.
• Stimulation decreased, while inhibition reversed, transmucosal potential differences and resistances.

Conclusions:

• Histamine is a highly effective stimulant of gastric acid secretion in rhesus monkeys.
• Metiamide's differential inhibition suggests distinct mechanisms for pentagastrin and histamine.
• Atropine's specificity highlights the role of muscarinic receptors in acetylcholine-mediated secretion.
• Electrophysiological changes correlate with acid secretion modulation.