2001 Volume 87 Issue 1 Pages 14-20
Gastric acid secretion has been proposed to be regulated by opioid receptors in the central nervous system (CNS). Previously, we reported that central injection of synthetic agonists of κ-opioid receptors stimulated gastric acid secretion in rats, and the secretion by the agonists was inhibited by norbinaltorphimine (an antagonist of κ-opioid receptor). In the present study, we investigated the effect of dynorphin A-(1 – 17), an endogenous ligand of κ-opioid receptor on the gastric acid secretion in the perfused stomach of urethane-anesthetized rats. Injection of dynorphin A-(1 – 17) (0.1 – 1 μg per rat) into the lateral cerebroventricle (LV) stimulated the secretion in a dose-dependent manner. The effect of dynorphin A-(1 – 17) was almost completely inhibited by the LV injection of norbinaltorphimine (10 μg) and in vagotomized rats. Although some studies of dynorphin A-(1 – 17) after central injection showed non-opioid effects such as the involvement of N-methyl-