[Influence of dermorphin on pancreatic secretion in the rat with gastric fistula]. / Influenza della dermorfina sulla secrezione pancreatica del ratto con fistola gastrica.

The influence of the opioid peptide dermorphin on 2DG-stimulated pancreatic secretion of the rat was studied. Experiments were performed in conscious rats with pancreatic fistulae (8 animals), or with pancreatic and gastric fistulae (8 rats) to allow diversion of gastric juice. In animals with gastric fistulae the peak of pancreatic protein output in response to 2DG was about 50% lower than in animals with intact stomachs. Dermorphin almost completely inhibited the stimulant effect of 2DG, independently by different experimental conditions. It is concluded that the increase of pancreatic secretion produced by 2DG is, at least in part, independent from the entrance of gastric acid into the duodenum. As a consequence, the inhibiting effect of dermorphin on 2DG-stimulated pancreatic secretion may be attributed to a decrease of vagal stimulation of the pancreas, at central and/or peripheral sites.

[Effect of a new opioid peptide on gastric secretion in the rat stimulated with 2-deoxyglucose]. / Effetto di un nuovo peptide oppioide sulla secrezione gastrica del ratto stimolata con 2-desossiglucosio.

Gastric secretion was studied in conscious rats with chronic gastric fistulae maintained in restraint cages. Experiments were performed 24 hours after surgical procedure: the stomachs were washed with 3 ml of saline and gastric acid determined by titration of pH 6 every 30 minutes. The i.v. injection of 75 mg/kg of 2DG strongly stimulated gastric secretion, with a 5-fold increase of acid output in comparison to control rats. The slow intravenous injection of dermorphin, 15 min before 2DG, dose-dependently inhibited the stimulant effect of the latter. Opioid activity of dermorphin has been reported (5); on the other hand, the intracerebroventricular injection of opiates has been shown to decrease the gastric secretion of the rat by Rozé et al. (3). The effectiveness of dermorphin given by intravenous route observed in present experiments seems to suggest the hypothesis that dermorphin (and other opiates) may act, besides central, also on peripheral sites.