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Kinetic Control of Multiple Forms of Ca(2+) Spikes by Inositol Trisphosphate in Pancreatic Acinar Cells

The mechanisms of agonist-induced Ca(2+) spikes have been investigated using a caged inositol 1,4,5-trisphosphate (IP(3)) and a low-affinity Ca(2+) indicator, BTC, in pancreatic acinar cells. Rapid photolysis of caged IP(3) was able to reproduce acetylcholine (ACh)-induced three forms of Ca(2+) spik...

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Detalles Bibliográficos
Autores principales: Ito, Koichi, Miyashita, Yasushi, Kasai, Haruo
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1999
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2156179/
https://www.ncbi.nlm.nih.gov/pubmed/10427093
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author Ito, Koichi
Miyashita, Yasushi
Kasai, Haruo
author_facet Ito, Koichi
Miyashita, Yasushi
Kasai, Haruo
author_sort Ito, Koichi
collection PubMed
description The mechanisms of agonist-induced Ca(2+) spikes have been investigated using a caged inositol 1,4,5-trisphosphate (IP(3)) and a low-affinity Ca(2+) indicator, BTC, in pancreatic acinar cells. Rapid photolysis of caged IP(3) was able to reproduce acetylcholine (ACh)-induced three forms of Ca(2+) spikes: local Ca(2+) spikes and submicromolar (<1 μM) and micromolar (1–15 μM) global Ca(2+) spikes (Ca(2+) waves). These observations indicate that subcellular gradients of IP(3) sensitivity underlie all forms of ACh-induced Ca(2+) spikes, and that the amplitude and extent of Ca(2+) spikes are determined by the concentration of IP(3). IP(3)-induced local Ca(2+) spikes exhibited similar time courses to those generated by ACh, supporting a role for Ca(2+)-induced Ca(2+) release in local Ca(2+) spikes. In contrast, IP(3)- induced global Ca(2+) spikes were consistently faster than those evoked with ACh at all concentrations of IP(3) and ACh, suggesting that production of IP(3) via phospholipase C was slow and limited the spread of the Ca(2+) spikes. Indeed, gradual photolysis of caged IP(3) reproduced ACh-induced slow Ca(2+) spikes. Thus, local and global Ca(2+) spikes involve distinct mechanisms, and the kinetics of global Ca(2+) spikes depends on that of IP(3) production particularly in those cells such as acinar cells where heterogeneity in IP(3) sensitivity plays critical role.
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spelling pubmed-21561792008-05-01 Kinetic Control of Multiple Forms of Ca(2+) Spikes by Inositol Trisphosphate in Pancreatic Acinar Cells Ito, Koichi Miyashita, Yasushi Kasai, Haruo J Cell Biol Original Article The mechanisms of agonist-induced Ca(2+) spikes have been investigated using a caged inositol 1,4,5-trisphosphate (IP(3)) and a low-affinity Ca(2+) indicator, BTC, in pancreatic acinar cells. Rapid photolysis of caged IP(3) was able to reproduce acetylcholine (ACh)-induced three forms of Ca(2+) spikes: local Ca(2+) spikes and submicromolar (<1 μM) and micromolar (1–15 μM) global Ca(2+) spikes (Ca(2+) waves). These observations indicate that subcellular gradients of IP(3) sensitivity underlie all forms of ACh-induced Ca(2+) spikes, and that the amplitude and extent of Ca(2+) spikes are determined by the concentration of IP(3). IP(3)-induced local Ca(2+) spikes exhibited similar time courses to those generated by ACh, supporting a role for Ca(2+)-induced Ca(2+) release in local Ca(2+) spikes. In contrast, IP(3)- induced global Ca(2+) spikes were consistently faster than those evoked with ACh at all concentrations of IP(3) and ACh, suggesting that production of IP(3) via phospholipase C was slow and limited the spread of the Ca(2+) spikes. Indeed, gradual photolysis of caged IP(3) reproduced ACh-induced slow Ca(2+) spikes. Thus, local and global Ca(2+) spikes involve distinct mechanisms, and the kinetics of global Ca(2+) spikes depends on that of IP(3) production particularly in those cells such as acinar cells where heterogeneity in IP(3) sensitivity plays critical role. The Rockefeller University Press 1999-07-26 /pmc/articles/PMC2156179/ /pubmed/10427093 Text en © 1999 The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Original Article
Ito, Koichi
Miyashita, Yasushi
Kasai, Haruo
Kinetic Control of Multiple Forms of Ca(2+) Spikes by Inositol Trisphosphate in Pancreatic Acinar Cells
title Kinetic Control of Multiple Forms of Ca(2+) Spikes by Inositol Trisphosphate in Pancreatic Acinar Cells
title_full Kinetic Control of Multiple Forms of Ca(2+) Spikes by Inositol Trisphosphate in Pancreatic Acinar Cells
title_fullStr Kinetic Control of Multiple Forms of Ca(2+) Spikes by Inositol Trisphosphate in Pancreatic Acinar Cells
title_full_unstemmed Kinetic Control of Multiple Forms of Ca(2+) Spikes by Inositol Trisphosphate in Pancreatic Acinar Cells
title_short Kinetic Control of Multiple Forms of Ca(2+) Spikes by Inositol Trisphosphate in Pancreatic Acinar Cells
title_sort kinetic control of multiple forms of ca(2+) spikes by inositol trisphosphate in pancreatic acinar cells
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2156179/
https://www.ncbi.nlm.nih.gov/pubmed/10427093
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