P/Q Ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells

Chromaffin cell exocytosis is triggered by Ca2+ entry through several voltage-dependent channel subtypes. Because it was postulated that immediately releasable vesicles are closely associated with Ca2+ channels, we wondered what channel types are specifically coupled to the release of this pool. To...

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Autores principales:	Álvarez, Y.D., Ibañez, L.I., Uchitel, O.D., Marengo, F.D.
Formato:	JOUR
Materias:	Stimulus-secretion coupling Voltage-dependent calcium channels α1A Knockout mice calcium channel calcium channel blocking agent calcium channel L type calcium channel N type calcium ion conotoxin nitrendipine snx 482 calcium channel P type calcium channel Q type animal cell animal cell culture article calcium transport cell vacuole chromaffin cell controlled study exocytosis fluorescence knockout mouse mouse nonhuman patch clamp priority journal stimulation stimulus wild type animal drug effect electric capacitance electrostimulation metabolism mouse mutant physiology Mus Animals Calcium Channel Blockers Calcium Channels Calcium Channels, P-Type Calcium Channels, Q-Type Chromaffin Cells Electric Capacitance Electric Stimulation Exocytosis Mice Mice, Knockout Patch-Clamp Techniques
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_01434160_v43_n2_p155_Alvarez
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

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spelling	todo:paper_01434160_v43_n2_p155_Alvarez2023-10-03T14:59:21Z P/Q Ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells Álvarez, Y.D. Ibañez, L.I. Uchitel, O.D. Marengo, F.D. Stimulus-secretion coupling Voltage-dependent calcium channels α1A Knockout mice calcium channel calcium channel blocking agent calcium channel L type calcium channel N type calcium ion conotoxin nitrendipine snx 482 calcium channel calcium channel blocking agent calcium channel P type calcium channel Q type animal cell animal cell culture article calcium transport cell vacuole chromaffin cell controlled study exocytosis fluorescence knockout mouse mouse nonhuman patch clamp priority journal stimulation stimulus wild type animal drug effect electric capacitance electrostimulation metabolism mouse mutant physiology Mus Animals Calcium Channel Blockers Calcium Channels Calcium Channels, P-Type Calcium Channels, Q-Type Chromaffin Cells Electric Capacitance Electric Stimulation Exocytosis Mice Mice, Knockout Patch-Clamp Techniques Chromaffin cell exocytosis is triggered by Ca2+ entry through several voltage-dependent channel subtypes. Because it was postulated that immediately releasable vesicles are closely associated with Ca2+ channels, we wondered what channel types are specifically coupled to the release of this pool. To study this question, cultured mouse chromaffin cell exocytosis was followed by patch-clamp membrane capacitance measurements. The immediately releasable pool was estimated using paired pulse stimulation, resulting in an upper limit of 31 ± 3 fF for control conditions (ICa: 25 ± 2 pA/pF). The N-type channel blocker ω-conotoxin-GVIA affected neither ICa nor the immediately releasable pool exocytosis; although the L channel blocker nitrendipine decreased current by 50%, it did not reduce this pool significantly; and the R channel inhibitor SNX-482 significantly reduced the current but induced only a moderate decrease in the estimated IRP exocytosis. In contrast, the P/Q channel blocker ω-Agatoxin-IVA decreased ICa by 37% but strongly reduced the immediately releasable pool (upper limit: 6 ± 1 fF). We used α1A subunit knockout mice to corroborate that P/Q Ca2+ channels were specifically linked to immediately releasable vesicles, and we found that also in this preparation the exocytosis of this pool was severely decreased (6 ± 1 fF). On the other hand, application of a strong stimulus that caused the fusion of most of releasable vesicles (3 min, 50 mM K+) induced similar exocytosis for wild type and knockout cells. Finally, whereas application of train stimulation on chromaffin cells derived from wild type mice provoked typical early synchronous and delayed asynchronous exocytosis components, the knockout derived cells presented a strongly depressed early exocytosis but showed a prominent delayed asynchronous component. These results demonstrate that P/Q are the dominant calcium channels associated to the release of immediately releasable pool in mouse chromaffin cells. © 2007 Elsevier Ltd. All rights reserved. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01434160_v43_n2_p155_Alvarez
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Stimulus-secretion coupling Voltage-dependent calcium channels α1A Knockout mice calcium channel calcium channel blocking agent calcium channel L type calcium channel N type calcium ion conotoxin nitrendipine snx 482 calcium channel calcium channel blocking agent calcium channel P type calcium channel Q type animal cell animal cell culture article calcium transport cell vacuole chromaffin cell controlled study exocytosis fluorescence knockout mouse mouse nonhuman patch clamp priority journal stimulation stimulus wild type animal drug effect electric capacitance electrostimulation metabolism mouse mutant physiology Mus Animals Calcium Channel Blockers Calcium Channels Calcium Channels, P-Type Calcium Channels, Q-Type Chromaffin Cells Electric Capacitance Electric Stimulation Exocytosis Mice Mice, Knockout Patch-Clamp Techniques
spellingShingle	Stimulus-secretion coupling Voltage-dependent calcium channels α1A Knockout mice calcium channel calcium channel blocking agent calcium channel L type calcium channel N type calcium ion conotoxin nitrendipine snx 482 calcium channel calcium channel blocking agent calcium channel P type calcium channel Q type animal cell animal cell culture article calcium transport cell vacuole chromaffin cell controlled study exocytosis fluorescence knockout mouse mouse nonhuman patch clamp priority journal stimulation stimulus wild type animal drug effect electric capacitance electrostimulation metabolism mouse mutant physiology Mus Animals Calcium Channel Blockers Calcium Channels Calcium Channels, P-Type Calcium Channels, Q-Type Chromaffin Cells Electric Capacitance Electric Stimulation Exocytosis Mice Mice, Knockout Patch-Clamp Techniques Álvarez, Y.D. Ibañez, L.I. Uchitel, O.D. Marengo, F.D. P/Q Ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells
topic_facet	Stimulus-secretion coupling Voltage-dependent calcium channels α1A Knockout mice calcium channel calcium channel blocking agent calcium channel L type calcium channel N type calcium ion conotoxin nitrendipine snx 482 calcium channel calcium channel blocking agent calcium channel P type calcium channel Q type animal cell animal cell culture article calcium transport cell vacuole chromaffin cell controlled study exocytosis fluorescence knockout mouse mouse nonhuman patch clamp priority journal stimulation stimulus wild type animal drug effect electric capacitance electrostimulation metabolism mouse mutant physiology Mus Animals Calcium Channel Blockers Calcium Channels Calcium Channels, P-Type Calcium Channels, Q-Type Chromaffin Cells Electric Capacitance Electric Stimulation Exocytosis Mice Mice, Knockout Patch-Clamp Techniques
description	Chromaffin cell exocytosis is triggered by Ca2+ entry through several voltage-dependent channel subtypes. Because it was postulated that immediately releasable vesicles are closely associated with Ca2+ channels, we wondered what channel types are specifically coupled to the release of this pool. To study this question, cultured mouse chromaffin cell exocytosis was followed by patch-clamp membrane capacitance measurements. The immediately releasable pool was estimated using paired pulse stimulation, resulting in an upper limit of 31 ± 3 fF for control conditions (ICa: 25 ± 2 pA/pF). The N-type channel blocker ω-conotoxin-GVIA affected neither ICa nor the immediately releasable pool exocytosis; although the L channel blocker nitrendipine decreased current by 50%, it did not reduce this pool significantly; and the R channel inhibitor SNX-482 significantly reduced the current but induced only a moderate decrease in the estimated IRP exocytosis. In contrast, the P/Q channel blocker ω-Agatoxin-IVA decreased ICa by 37% but strongly reduced the immediately releasable pool (upper limit: 6 ± 1 fF). We used α1A subunit knockout mice to corroborate that P/Q Ca2+ channels were specifically linked to immediately releasable vesicles, and we found that also in this preparation the exocytosis of this pool was severely decreased (6 ± 1 fF). On the other hand, application of a strong stimulus that caused the fusion of most of releasable vesicles (3 min, 50 mM K+) induced similar exocytosis for wild type and knockout cells. Finally, whereas application of train stimulation on chromaffin cells derived from wild type mice provoked typical early synchronous and delayed asynchronous exocytosis components, the knockout derived cells presented a strongly depressed early exocytosis but showed a prominent delayed asynchronous component. These results demonstrate that P/Q are the dominant calcium channels associated to the release of immediately releasable pool in mouse chromaffin cells. © 2007 Elsevier Ltd. All rights reserved.
format	JOUR
author	Álvarez, Y.D. Ibañez, L.I. Uchitel, O.D. Marengo, F.D.
author_facet	Álvarez, Y.D. Ibañez, L.I. Uchitel, O.D. Marengo, F.D.
author_sort	Álvarez, Y.D.
title	P/Q Ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells
title_short	P/Q Ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells
title_full	P/Q Ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells
title_fullStr	P/Q Ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells
title_full_unstemmed	P/Q Ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells
title_sort	p/q ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells
url	http://hdl.handle.net/20.500.12110/paper_01434160_v43_n2_p155_Alvarez
work_keys_str_mv	AT alvarezyd pqca2channelsarefunctionallycoupledtoexocytosisoftheimmediatelyreleasablepoolinmousechromaffincells AT ibanezli pqca2channelsarefunctionallycoupledtoexocytosisoftheimmediatelyreleasablepoolinmousechromaffincells AT uchitelod pqca2channelsarefunctionallycoupledtoexocytosisoftheimmediatelyreleasablepoolinmousechromaffincells AT marengofd pqca2channelsarefunctionallycoupledtoexocytosisoftheimmediatelyreleasablepoolinmousechromaffincells
_version_	1807324295005732864

P/Q Ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells

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