A bimodal pattern of InsP(3)-evoked elementary Ca(2+) signals in pancreatic acinar cells
Biomedical Imaging Group
Animals; Biophysics; Calcium Channels; Calcium Signaling; Female; Inositol 1,4,5-Trisphosphate; Inositol 1,4,5-Trisphosphate Receptors; Male; Mice; Microscopy, Fluorescence; Oocytes; Pancreas; Patch-Clamp Techniques; Protein Isoforms; Receptors, Cytoplasmic and Nuclear; Xenopus
Life Sciences | Medicine and Health Sciences
InsP(3)-evoked elementary Ca(2+) release events have been postulated to play a role in providing the building blocks of larger Ca(2+) signals. In pancreatic acinar cells, low concentrations of acetylcholine or the injection of low concentrations of InsP(3) elicit a train of spatially localized Ca(2+) spikes. In this study we have quantified these responses and compared the Ca(2+) signals to the elementary events shown in Xenopus oocytes. The results demonstrate, at the same concentrations of InsP(3), Ca(2+) signals consisting of one population of small transient Ca(2+) release events and a second distinct population of larger Ca(2+) spikes. The signal mass amplitudes of both types of events are within the range of amplitudes for the elementary events in Xenopus oocytes. However, the bimodal Ca(2+) distribution of Ca(2+) responses we observe is not consistent with the continuum of event sizes seen in Xenopus. We conclude that the two types of InsP(3)-dependent events in acinar cells are both elementary Ca(2+) signals, which are independent of one another. Our data indicate a complexity to the organization of the Ca(2+) release apparatus in acinar cells, which might result from the presence of multiple InsP(3) receptor isoforms, and is likely to be important in the physiology of these cells.
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Citation: Biophys J. 2000 May;78(5):2298-306.
DOI of Published Version
Fogarty, Kevin E.; Kidd, Jackie F.; Tuft, Richard A.; and Thorn, Peter, "A bimodal pattern of InsP(3)-evoked elementary Ca(2+) signals in pancreatic acinar cells" (2000). Open Access Articles. 270.