Alpha-2-adrenoceptor-mediated inhibition of vagally induced gastric acid secretion with the anti-ulcer agent DQ-2511.

Effects of DQ-2511, a new peripherally acting anti-ulcer agent, on vagally induced gastric acid output and mucosal blood flow (MBF) were investigated in urethane-anesthetized rats with gastric fistula. Intravenous infusion of DQ-2511 (2 or 20 mg/kg/hr, for 30 min) reduced the vagally induced gastric acid output and MBF, and these inhibitory effects were abolished by pretreatment with phentolamine. The DQ-2511-induced inhibition of acid output was abolished with yohimbine, but not with prazosin. These observations suggest that DQ-2511 possesses the properties of an adrenergic alpha-2-adrenoceptor agonist. DQ-2511 presumably acts on adrenergic alpha-2-adrenoceptors located on the parasympathetic neurons in the gastric wall, thereby reducing the vagally-induced gastric acid output.