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Effects of morphine and naloxone on canine pancreatic secretion induced by acidified duodenum

Chen Qi, Zhang Wanqin, Mei Maohua

Research Group of Gastroenterology, Department of Physiology, Dalian Medical College. Liaoning, China

Abstract

Five mongrel dogs were prepared with chronic gastric and pancreatic fistula before experiment for insertion of cannula and collection of pancreatic juice. Pancreatic secretion stimulated by infusion of 0.1 N HC1 into the duodenum,can be prevented by i. v. injection of morphine and/or naloxone. The volume of pancreatic secretion and the concentrations of bicarbonate and protein in the juice were assayed. The effects of morphine and/or naloxone on the tension of the muscular strip of main pancreatic duct were also observed in vitro in six dogs. The results were as follows: (1) Morphine inhibited the volume of pancreatic secretion and decreased bicarbonate and protein outputs (P<0.05) but did not affect bicarbonate and protein concentrations, (2) Naloxone per se had no effect on either pancreatic secretion or biocarbonate and protein concentrations. (3) However, it would increase the inhibitory effect of morphine on pancreatic secretion (P<0.01). (4) Morphine increased the tension of the muscular strip of the main pancreatic duct in vitro but this was not affected by naloxone. Taking all these observations together, the present study suggests that the inhibitory effect of morphine on pancreatic bicarbonate and protein outputs may be due to its contracting effect on pancreatic duct.

Key words: Pancreatic secretion;Bicarbonate output;Protein output;Morphine;Naloaone;Tension of pancreatic duct

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Citing This Article：

Chen Qi, Zhang Wanqin, Mei Maohua. Effects of morphine and naloxone on canine pancreatic secretion induced by acidified duodenum. Acta Physiol Sin 1985; 37 (3): (in Chinese with English abstract).