Autoradiographic localization of opioid receptors in the rat stomach.

The distribution of opioid receptors in the stomach has been studied using autoradiography of slide-mounted tissue sections incubated with [3H]D-Ala2,D-Leu5-enkephalin. The major sites of binding were the mucosa and the submucosal and deep muscular plexi. Other regions did not exhibit significant binding. These locations suggest that endogenous delta-opioid receptors may regulate mucosal ion transport and smooth muscle motility in the stomach.