Control of secretion from rat stomach ECL cells in situ and in primary culture

The acid-producing part of the stomach is rich in peptide-hormone-producing endocrine/paracrine cells of different types. In birds and all mammals stu died, ECL cells constitute the quantitatively predominant endocrine cell po pulation in this location. They produce histamine and an as yet unidentifie d peptide. hormone. The paracrine. action of the ECL cells is to provide hi stamine to mediate the stimulating effect of gastrin on the acid-secreting parietal cells: the gastrin-ECL cell-parietal cell axis. Secretion of histamine from the ECL cells was studied in intact conscious r ats subjected to gastric submucosal microdialysis and using isolated cells in primary culture. The microdialysis experiments revealed that ECL-cell hi stamine can be mobilized by the local infusion of gastrin, pituitary adenyl ate cyclase-activating peptide (PACAP), vasoactive intestinal peptide (VIP) , peptide YY (PYY), met-enkephalin, endothelin and noradrenaline/adrenaline . While gastrin and met-enkephalin induced a sustained elevation of the sub mucosal histamine concentration, endothelin, PYY, PACAP, VIP, and noradrena line/adrenaline induced a transient elevation. Somatostatin, galanin and th e prostanoid, misoprostol, inhibited gastrin-stimulated histamine mobilizat ion. Studies of isolated ECL cells (80-90% purity) showed gastrin, PACAP an d VIP to stimulate histamine secretion and somatostatin, galanin and misopr ostol to inhibit gastrin-stimulated secretion. At present, it seems unlikel y that metenkephalin, endothelin, adrenaline and PYY act directly on the EC L cells in situ since the effects could not be reproduced with isolated ECL cells. Clearly, the ECL cells operate under the multifactorial control of circulating hormones, local hormones, catecholamines, neuropeptides and inf lammatory mediators.