Effect of cysteamine on gastroduodenal mucosal histamine in rat.

Cysteamine administration to rats is followed by a high incidence of peptic ulceration. The aim of the present study was to investigate the effect of cysteamine on gastric and duodenal mucosal histamine and gastric mucosal histamine formation capacity. After a four hour fast, cysteamine in doses of 50, 100, 200, 300, 400, and 500 mg/kg bodyweight was injected subcutaneously to male Wistar rats; saline injection was used as control. After 24 hours the animals were killed; the stomach and duodenum were removed and examined for ulceration. Mucosal biopsies were taken for histamine studies. Gastric and duodenal ulceration tended to appear with increasing incidence with higher doses. A direct correlation was found between the dose of cysteamine and gastric mucosal histamine (p less than 0.02), and duodenal mucosal histamine (p less than 0.05). Further, a direct relationship was found between gastric mucosal histidine decarboxylase activity and the dose of cysteamine (p less than 0.05). Gastric mucosal histamine and histidine decarboxylase activity showed a direct correlation (p less than 0.001). Gastric and duodenal mucosal histamine and gastric mucosal histamine formation capacity were higher in rats with ulcers than in controls and rats without ulcers. In rat, cysteamine induces dose related changes in mucosal histamine and histidine decarboxylase activity. These changes are related to ulcer formation; histamine may be involved in the pathophysiology of cysteamine induced ulcer formation.