Secretagogue effects on intracellular calcium in pancreatic duct cells

• Published in: Pflügers Archiv 1990-08, Vol.416 (6), p.652-658
• Main Authors: STUENKEL, E. L, HOOTMAN, S. R
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Calcium - metabolism; Carbachol - pharmacology; Cell Membrane Permeability - drug effects; Cell Membrane Permeability - physiology; Cholecystokinin - pharmacology; Exocrine pancreas; Fundamental and applied biological sciences. Psychology; Guinea Pigs; Male; Pancreatic Ducts - cytology; Pancreatic Ducts - drug effects; Pancreatic Ducts - metabolism; Rats; Rats, Inbred Strains; Secretin - pharmacology; Vertebrates: digestive system
• ISSN: 0031-6768; 1432-2013
• DOI: 10.1007/bf00370610

Regulation of intracellular free calcium ([Ca2+]i) in single epithelial duct cells of isolated rat and guinea pig pancreatic interlobular ducts by secretin, carbachol and cholecystokinin was studied by microspectrofluorometry using the Ca2(+)-sensitive, fluorescent probe Fura-2. Rat and guinea pig duct cells exhibited mean resting [Ca2+]i of 84 nM and 61 nM, respectively, which increased by 50%-100% in response to carbachol stimulation, thus demonstrating the presence of physiologically responsive cholinergic receptors in pancreatic ducts of both species. The carbachol-induced increase in [Ca2+]i involved both mobilization of Ca2+ from intracellular stores and stimulation of influx of extracellular Ca2+. In contrast, neither cholecystokinin nor secretin showed reproducible or sizeable increases in [Ca2+]i. Both rat and guinea pig duct cells showed considerable resting Ca2+ permeability. Lowering or raising the extracellular [Ca2+]i led, respectively, to a decrease or increase in the resting [Ca2+]i. Application of Mn2+ resulted in a quenching of the fluorescence signal indicating its entry into the cell. The resting Ca2+ and Mn2+ permeability could be blocked by La3+ suggesting that it is mediated by a Ca2+ channel.