Intracellular Ca2+ signals in human-derived pancreatic somatostatin-secreting cells (QGP-1N)

Squires, Paul E., Amiranoff, Brigitte and Dunne, Mark J. (1994) Intracellular Ca2+ signals in human-derived pancreatic somatostatin-secreting cells (QGP-1N). Pflugers Archiv European Journal of Physiology, 428 (3-4). pp. 275-282. ISSN 0031-6768

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Single-cell microfluorimetry techniques have been used to examine the effects of acetylcholine (0.1-100 μM) on the intracellular free calcium ion concentration (Ca2+i) in a human-derived pancreatic somatostatin-secreting cell line, QGP-1N. When applied to the bath solution, acetylcholine was found to evoke a marked and rapid increase in Ca2+i at all concentrations tested. These responses were either sustained, or associated with the generation of complex patterns of Ca2+i transients. Overall, the pattern of response was concentration related. In general, 0.1-10 μM acetylcholine initiated a series of repetitive oscillations in cytoplasmic Ca2+, whilst at higher concentrations the responses consisted of a rapid rise in Ca2+i followed by a smaller more sustained increase. Without external Ca2+, 100 μM acetylcholine caused only a transient rise in Ca2+i, whereas lower concentrations of the agonist were able to initiate, but not maintain, Ca2+i oscillations. Acetylcholine-evoked Ca2+ signals were abolished by atropine (1-10 μM), verapamil (100 μM) and caffeine (20 mM). Nifedipine failed to have any significant effect upon agonist-evoked increases in Ca2+i, whilst 50 mM KCl, used to depolarise the cell membrane, only elicited a transient increase in Ca2+i. Ryanodine (50-500 nM) and caffeine (1-20 mM) did not increase basal Ca2+ levels, but the Ca2+-ATPase inhibitors 2,5-di(tert-butyl)-hydroquinone (TBQ) and thapsigargin both elevated Ca2+i levels. These data demonstrate for the first time cytosolic Ca2+ signals in single isolated somatostatin-secreting cells of the pancreas. We have demonstrated that acetylcholine will evoke both Ca2+ influx and Ca2+ mobilisation, and we have partially addressed the subcellular mechanism responsible for these events. © 1994 Springer-Verlag.

Keywords:acetylcholine, caffeine, calcium, ryanodine, somatostatin, terpene, thapsigargin, 2,5 di tert butylhydroquinone, atropine, verapamil, article, cell line, cytology, cytosol, human, intracellular membrane, metabolism, pancreas, signal transduction, calcium cell level, calcium homeostasis, fluorometry, human cell, oscillation, pancreas cell, pancreas islet, priority journal, somatostatin release, Acetylcholine, Intracellular Membranes, Support, Non-U.S. Gov't, Terpenes
Subjects:C Biological Sciences > C130 Cell Biology
Divisions:College of Science > School of Life Sciences
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ID Code:14513
Deposited On:16 Jul 2014 15:52

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