Acid and hyperosmolal solutions in the upper intestine of chronic gastric fistula rats inhibit gastric acid secretion by different mechanisms.
In chronic gastric fistula rats 0.20 M HCl and 1200 mOsm X kg-1 solution of polyethylene glycol (PEG) infused into a duodenal loop anastomosed to the jejunum (Roux-en-Y) produced maximal inhibition of pentagastrin-stimulated acid secretion, which amounted to 60% and 50%, respectively. In the present study in Roux-en-Y rats with gastric fistula, perfusion of the loop with hyperosmolal (1200 mOsm X kg-1 of PEG solution) 0.20 M HCl produced a greater reduction of the maximal response to pentagastrin (91% inhibition) than perfusion with 0.20 M HCl (64%), suggesting that HCl and hyperosmolal solution inhibit secretion by different mechanisms. The maximal acid response to histamine was more resistant to inhibition than that to pentagastrin; 0.20 M HCl inhibited secretion by 43%, 1200 mOsm X kg-1 of PEG solution by 42%, and hyperosmolal 0.20 M HCl by 60%. The results suggest that HCl and hyperosmolal solution also inhibit histamine-stimulated secretion by different mechanisms. The anatomical sites of the mechanisms remain to be established.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005744:Gastric Acid / Q000378:metabolism*; D006632:Histamine / Q000494:pharmacology; D006633:Histamine Antagonists / Q000494:pharmacology; D006851:Hydrochloric Acid / Q000494:pharmacology; D007583:Jejunum / Q000187:drug effects*; D008297:Male; D010418:Pentagastrin / Q000037:antagonists & inhibitors; D011092:Polyethylene Glycols / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012636:Secretory Rate / Q000187:drug effects; D013270:Stomach / Q000502:physiology*
D006633:Histamine Antagonists; D011092:Polyethylene Glycols; D006632:Histamine; D010418:Pentagastrin; D006851:Hydrochloric Acid