Dibenamine blockade on gastric acid secretion in vitro and its protection by histamine antagonists

Experiments to protect the histamine receptor against dibenamine blockade were carried out to elucidate the pharmacological characteristics of the H2-histamine receptor system for gastric acid secretion in isolated bullfrog gastric mucosa. Dibenamine alone (5 times 10-minus 5 g/ml) irreversibly blocked both basal and histamine-stimulated acid secretion. However, when the preparation was treated with dibenamine in combination with histamine (1 times 10-minus 5 g/ml) irreversibly blocked both basal and histamine-stimulated acid secretion. However, when the preparation was treated with dibenamine in combination with histamine (1 times 10-minus 5 g/ml), the acid secretory response to histamine was restored after washing out dibenamine. Burimamide, an H2-receptor antagonist, also protected the histamine sensitivity against dibenamine blockade in the concentration of 1 times 10-minus 4 g/ml. Diphenhydramine and pyribenzamine were also protected with histamine receptor against dibenamine blockade. The acid secretion induced by the action of histamine on the diphenhydramine-protected receptor was antagonized by diphenhydramine as well as burimamide.