The role of histamine in changes which occur in the gastric mucosal barrier with bile damage.

H1 and H2 histamine receptor antagonists were used in dogs with Heidenhain pouches during experiments in which the mucosa was damaged with sodium taurocholate. In these experiments when both antagonists were used together the usual increase in hydrogen and sodium ion flux across the mucosa was not observed, but the usual fall in transmucosal potential difference occurred. The results suggest that mucosal histamine probably mediates the changes in ionic flux across gastric mucosa which follow exposure to bile. Attempts to establish the source of this histamine were made in both rats and dogs using compound 48/80 over a period to degranulate the mast cells. Treatment with this compound did not affect the change in ionic fluxes which followed exposure to bile acid, suggesting that the source of histamine mediating changes in ionic flux is probably from tissue sites other than mast cells.