Quantifying calcium fluxes underlying calcium puffs in Xenopus laevis oocytes

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We determine the calcium fluxes through inositol 1,4,5-trisphosphate receptor/channels underlying calcium puffs of Xenopus laevis oocytes using a simplified version of the algorithm of Ventura et al. [1]. An analysis of 130 puffs obtained with Fluo-4 indicates that Ca2+ release comes from a region o...

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Autores principales:	Bruno, Luciana, Solovey, Guillermo, Ventura, Alejandra C., Ponce Dawson, Silvina
Publicado:	2010
Materias:	Backward methods Calcium fluxes Confocal microscopy IP3Rs Puffs Xenopus laevis calcium ion dye inositol 1,4,5 trisphosphate receptor algorithm animal cell article calcium current calcium transport controlled study nonhuman oocyte priority journal simulation statistical model Neptunia
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01434160_v47_n3_p273_Bruno http://hdl.handle.net/20.500.12110/paper_01434160_v47_n3_p273_Bruno
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_01434160_v47_n3_p273_Bruno
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spelling	paper:paper_01434160_v47_n3_p273_Bruno2023-06-08T15:11:52Z Quantifying calcium fluxes underlying calcium puffs in Xenopus laevis oocytes Bruno, Luciana Solovey, Guillermo Ventura, Alejandra C. Ponce Dawson, Silvina Backward methods Calcium fluxes Confocal microscopy IP3Rs Puffs Xenopus laevis calcium ion dye inositol 1,4,5 trisphosphate receptor algorithm animal cell article calcium current calcium transport controlled study nonhuman oocyte priority journal simulation statistical model Xenopus laevis Neptunia Xenopus laevis We determine the calcium fluxes through inositol 1,4,5-trisphosphate receptor/channels underlying calcium puffs of Xenopus laevis oocytes using a simplified version of the algorithm of Ventura et al. [1]. An analysis of 130 puffs obtained with Fluo-4 indicates that Ca2+ release comes from a region of width ∼450 nm, that the release duration is peaked around 18 ms and that the underlying Ca2+ currents range between 0.12 and 0.95 pA. All these parameters are independent of IP3 concentration. We explore what distributions of channels that open during a puff, Np, and what relations between current and number of open channels, I(Np), are compatible with our findings and with the distribution of puff-to-trigger amplitude ratio reported in Rose et al. [2]. To this end, we use simple "mean field" models in which all channels open and close simultaneously. We find that the variability among clusters plays an important role in shaping the observed puff amplitude distribution and that a model for which I(Np) ∼ Np for small Np and I (Np) ∼ Np 1 / α (α > 1) for large Np, provides the best agreement. Simulations of more detailed models in which channels open and close stochastically show that this nonlinear behavior can be attributed to the limited time resolution of the observations and to the averaging procedure that is implicit in the mean-field models. These conclusions are also compatible with observations of ∼400 puffs obtained using the dye Oregon green. © 2009 Elsevier Ltd. All rights reserved. Fil:Bruno, L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Solovey, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Ventura, A.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Dawson, S.P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2010 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01434160_v47_n3_p273_Bruno http://hdl.handle.net/20.500.12110/paper_01434160_v47_n3_p273_Bruno
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Backward methods Calcium fluxes Confocal microscopy IP3Rs Puffs Xenopus laevis calcium ion dye inositol 1,4,5 trisphosphate receptor algorithm animal cell article calcium current calcium transport controlled study nonhuman oocyte priority journal simulation statistical model Xenopus laevis Neptunia Xenopus laevis
spellingShingle	Backward methods Calcium fluxes Confocal microscopy IP3Rs Puffs Xenopus laevis calcium ion dye inositol 1,4,5 trisphosphate receptor algorithm animal cell article calcium current calcium transport controlled study nonhuman oocyte priority journal simulation statistical model Xenopus laevis Neptunia Xenopus laevis Bruno, Luciana Solovey, Guillermo Ventura, Alejandra C. Ponce Dawson, Silvina Quantifying calcium fluxes underlying calcium puffs in Xenopus laevis oocytes
topic_facet	Backward methods Calcium fluxes Confocal microscopy IP3Rs Puffs Xenopus laevis calcium ion dye inositol 1,4,5 trisphosphate receptor algorithm animal cell article calcium current calcium transport controlled study nonhuman oocyte priority journal simulation statistical model Xenopus laevis Neptunia Xenopus laevis
description	We determine the calcium fluxes through inositol 1,4,5-trisphosphate receptor/channels underlying calcium puffs of Xenopus laevis oocytes using a simplified version of the algorithm of Ventura et al. [1]. An analysis of 130 puffs obtained with Fluo-4 indicates that Ca2+ release comes from a region of width ∼450 nm, that the release duration is peaked around 18 ms and that the underlying Ca2+ currents range between 0.12 and 0.95 pA. All these parameters are independent of IP3 concentration. We explore what distributions of channels that open during a puff, Np, and what relations between current and number of open channels, I(Np), are compatible with our findings and with the distribution of puff-to-trigger amplitude ratio reported in Rose et al. [2]. To this end, we use simple "mean field" models in which all channels open and close simultaneously. We find that the variability among clusters plays an important role in shaping the observed puff amplitude distribution and that a model for which I(Np) ∼ Np for small Np and I (Np) ∼ Np 1 / α (α > 1) for large Np, provides the best agreement. Simulations of more detailed models in which channels open and close stochastically show that this nonlinear behavior can be attributed to the limited time resolution of the observations and to the averaging procedure that is implicit in the mean-field models. These conclusions are also compatible with observations of ∼400 puffs obtained using the dye Oregon green. © 2009 Elsevier Ltd. All rights reserved.
author	Bruno, Luciana Solovey, Guillermo Ventura, Alejandra C. Ponce Dawson, Silvina
author_facet	Bruno, Luciana Solovey, Guillermo Ventura, Alejandra C. Ponce Dawson, Silvina
author_sort	Bruno, Luciana
title	Quantifying calcium fluxes underlying calcium puffs in Xenopus laevis oocytes
title_short	Quantifying calcium fluxes underlying calcium puffs in Xenopus laevis oocytes
title_full	Quantifying calcium fluxes underlying calcium puffs in Xenopus laevis oocytes
title_fullStr	Quantifying calcium fluxes underlying calcium puffs in Xenopus laevis oocytes
title_full_unstemmed	Quantifying calcium fluxes underlying calcium puffs in Xenopus laevis oocytes
title_sort	quantifying calcium fluxes underlying calcium puffs in xenopus laevis oocytes
publishDate	2010
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01434160_v47_n3_p273_Bruno http://hdl.handle.net/20.500.12110/paper_01434160_v47_n3_p273_Bruno
work_keys_str_mv	AT brunoluciana quantifyingcalciumfluxesunderlyingcalciumpuffsinxenopuslaevisoocytes AT soloveyguillermo quantifyingcalciumfluxesunderlyingcalciumpuffsinxenopuslaevisoocytes AT venturaalejandrac quantifyingcalciumfluxesunderlyingcalciumpuffsinxenopuslaevisoocytes AT poncedawsonsilvina quantifyingcalciumfluxesunderlyingcalciumpuffsinxenopuslaevisoocytes
_version_	1768546014783864832

Quantifying calcium fluxes underlying calcium puffs in Xenopus laevis oocytes

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