| Abstract: | In chronic gastric fistula rats 0.20 M HC1 and 1200 mOsm × 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 × kg-1 of PEG solution) 0.20 M HC1 produced a greater reduction of the maximal response to pentagastrin (91% inhibition) than perfusion with 0.20 M HC1 (64%), suggesting that HC1 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 HC1 inhibited secretion by 43%, 1200 mOsm × kg-1 of PEG solution by 42%, and hyperosmolal 0.20 M HC1 by 60%. The results suggest that HC1 and hyperosmolal solution also inhibit histamine-stimulated secretion by different mechanisms. The anatomical sites of the mechanisms remain to be established. |
