Amiloride is a cholinergic antagonist in the rabbit pancreas

• Published in: Biochimica et biophysica acta Vol. 804; no. 2; pp. 237 - 244
• Main Authors: Kuijpers, G.A.J., De Pont, J.J.H.H.M., Van Nooy, I.G.P., Fleuren-Jakobs, A.M.M., Bonting, S.L., Rodrigues de Miranda, J.F.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 19.06.1984; Elsevier; North-Holland
• Subjects: Acetylcholine - antagonists & inhibitors; Amiloride; Amiloride - pharmacology; Amylase secretion; Amylases - metabolism; Animals; Biological and medical sciences; Calcium - metabolism; Carbachol - pharmacology; Cholinergic antagonist; Exocrine pancreas; Fundamental and applied biological sciences. Psychology; In Vitro Techniques; Kinetics; Pancreas - physiology; Pancreatic Juice - drug effects; Pancreatic Juice - metabolism; Pyrazines - pharmacology; Quinuclidinyl Benzilate - metabolism; Rabbit pancreas; Rabbits; Receptors, Muscarinic - drug effects; Receptors, Muscarinic - metabolism; Vertebrates: digestive system; Rabbit pancreas; Amiloride; QNB; PzO; Cholinergic antagonist; Amylase secretion; Vertebrata; Mammalia; Rabbit; Acetylcholine; Antagonist; Exocrine secretion; Lagomorpha; Pancreas
• ISSN: 0167-4889; 0006-3002; 1879-2596; 1878-2434
• DOI: 10.1016/0167-4889(84)90155-1

The effect of amiloride on fluid and protein secretion in the isolated rabbit pancreas and on amylase secretion in rabbit pancreatic acini has been studied. Amiloride (1 mM) has no effect on the pancreatic fluid secretion either in a normal incubation medium (143 mM Na +), or in a medium containing only 25 mM Na +. The carbachol-induced enzyme secretion is inhibited by amiloride in both systems, whereas the enzyme secretion induced by the C-terminal octapeptide of cholecystokinin (PzO) is not affected. Amiloride also inhibits the carbachol-induced 45Ca efflux from rabbit pancreatic acini, but again not that induced by PzO. The amiloride concentrations for half-maximal inhibition of carbachol-induced amylase secretion and 45Ca efflux are 40 and 80 μM, respectively. Amiloride also competitively inhibits the specific binding of [ 3H]quinuclidinyl benzylate ([ 3H]QNB) to rabbit pancreatic acini, suggesting that the amiloride effect is due to competition on the level of the muscarinic acetylcholine receptor.