A bimodal pattern of InsP(3)-evoked elementary Ca(2+) signals in pancreatic acinar cells

UMMS Affiliation

Biomedical Imaging Group

Publication Date


Document Type



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.

DOI of Published Version



Biophys J. 2000 May;78(5):2298-306.

Journal/Book/Conference Title

Biophysical journal

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