Studies on some mechanisms of the enzyme secretion of exocrine pancreas in dogs

의학과/박사[한글] [영문] Pavlov and his associates (1888, 1893) developed experimental technics for the study of pancreatic secretion and demonstrated that stimulation of the peripheral ends of vagus nerve caused a flow of Pancreatic juice from pancreatic fistula in the unanesthetized dog, but failed to obtain similar results in acute experiments. Pavlov interpreted that vagi convey two kind of fibers to the pancreas, excitatory and inhibitory. Further he concluded that both vasoconstrictor and secretory fibers to the pancreas were present in the sympathetics. Popielski (1901), and lately Thomas (1950) has proposed a concept that local reflexes meditated through the intrinsic ganglion of the pancreas and the enteric plexus, or through the sympathetic ganglia, play in the response of the pancreas to excitants, particularly, those which increase enzyme output. On the basis of animal and human experiment Hong et al (1956, 1961) postulated the Possibility that a role of the local nerves suggested by Thomas (1950) is to release pancreas stimulating hormones from the duodenum. In order to access the role of local reflex in the regulation of enzyme secretion of the pancreas, author has studied the effects of a potent muscarinic ganglionic stimulant and its blockade or other related agents on pancreatic secretion in the presence of a secretin background in wish chloralose anesthetized dogs. Dogs between 8 and 16 kg were anesthetized with chloralose, approximately 60 mg/kg in propylene glycol after prime thiopental anesthesia (25 mg/kg). The abdominal cavity was opened, the main pancreatic duct cannulated end the accessory duct ligated. A tribe inserted into stomach for drain of gastric juice or the pylorus was ligated. All agents were injected intravenously through the polyethylene tube put in femoral vein. Seoretin (Jorpes and Mutt preparation) was infused throughout the experiment. Other agents are as follows; epinephrine and norepinephrine, new ganglionic stimulants: McN-A-343 and AHR-602, and SKF-525-A which is known to Potentiates the action of the various drugs, and ganglionic blocking agents: atropine and hexamethonium. Pancreatic juice in the presence of a secretin background was collected since there is very little flow of pancreatic juice in the fasted anesthetized dog. The pancreatic amylase, lipase and trypsin were measured by the methods previously described(Hong, 1967). Summary In dogs with chloralose anesthesia following a prime dose of thiopental the secretory response of pancreatic enzyme to secretin was studied by means of some agents active at autonomic ganglionic sites and obtained the following results. 1. Both epinephrine and norepinephrine reduced the volume response to secretin by the raising dose, however, the enzyme output was moderately increased only by the latter. 2. SKF-525-A increased the enzyme content in secretin juice. 3. Both AHR-602 and McH-A-343, muscarinic ganglionic stimulants increased the enzyme content of secretin juice and particularly the latter was a potent stimulant of enzyme secretion. 4. Both atropine and hexamethonium significantly reduced the pancreatic response to SKF-525-A, AHR-602 and McN-A-343, however, the former is more susceptible of enzyme response and the latter was of volume response. By these results it is concluded that pancreatic secretion can be elicited in part through autonomic ganglionic sites which are sensitive to both atropine and hexamethonium. However, the response of enzyme is more depend on atropine sensitive receptors and the volume response is on hexamethonium-sensitive sites. Consequently it is felt that the local reflex mechanists may explain in some extent the enzyme secretion of the pancreas, whereas, the ganglionic sites responsible for enzyme secretion appears to be cholinergic nature of atropine specific.restrictio