Gastrin induction of histamine release from primary cultures of canine oxyntic mucosal cells

Using enzyme-dispersed canine oxyntic mucosal cells, we studied regulation of histamine release from fractions in which mast cells were largely removed by density gradient. Histamine-like immunoreactivity was demonstrated using peroxidase-anti-peroxidase immunohistochemistry. Histamine-containing cells in the small cell elutriator fractions (SCEF) were further separated by albumin step density gradients. Approximately 2.5% of cells in the low density fraction (LDF) contained histamine-like immunoreactivity; this fraction was largely depleted of the more dense mast cells (0.5%). These two fractions were cultured for 48-64 h on a Matrigel substrate. The cell content of histamine and release into the medium were measured by radioenzymatic assay. Gastrin, carbachol, and forskolin increased histamine release from the LDF. The induction of histamine release by gastrin was evident within 5 min and was sustained for at least 60 min. The response to gastrin was dose dependent between concentrations of 10(-11) and 10(-8) M. In contrast, in the mast cell-enriched SCEF, basal release was higher and gastrin was without effect; however, concanavalin A stimulated and epinephrine inhibited histamine release indicating that histamine-release mechanisms were intact in this fraction. Our methods provide a preparation of low density oxyntic mucosal histamine cells that demonstrate gastrin-responsive histamine release; we speculate that enterochromaffin-like cells account for this gastrin response.