Immune-related intestinal Cl- secretion. I. Effect of histamine on the T84 cell line

The mast cell mediator, histamine, induces a rapid and transient increase in chloride secretion across monolayers of the human colonic epithelial cell line, T84. Threshold stimulation occurred at 3 X 10(-6) M histamine and a maximal effect at 10(-4) M. The effect was reproduced by the H1 agonists 2-methylhistamine and 2-pyridylethylamine, but not by the H2 agonists 4-methylhistamine and dimaprit, suggesting the involvement of an H1 receptor. Additionally, histamine's action was inhibited by an H1 antagonist, diphenhydramine, but not by an H2 antagonist, cimetidine. Histamine treatment increased free cytosolic calcium levels, but not those of adenosine 3',5'-cyclic monophosphate (cAMP) or guanosine 3',5'-cyclic monophosphate (cGMP). The mechanism of chloride secretion induced by histamine resembled that of carbachol, in that both 1) were associated with an increase in free cytosolic calcium, 2) had a site of activation at a basolaterally localized K+ channel, and 3) were potentiated by both cAMP- and cGMP-mediated secretagogues. These results suggest that histamine may act as an intestinal secretagogue via direct interactions with epithelial cells.