Control of dual isoforms of Ca2+ release channels in muscle

Here we compare excitation-contraction coupling in single muscle cells of frogs and rats. Because amphibians have isoform 3 (or b) of the ryanodine receptor/Ca2+ release channel, in addition to 1 (a), which is also present in the mammal, any extra feature present in the frog may in principle be attr...

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Autores principales:	RÍOS,EDUARDO, ZHOU,JINGSONG
Lenguaje:	English
Publicado:	Sociedad de Biología de Chile 2004
Materias:	Excitation-contraction coupling sarcoplasmic reticulum Ca2+ sparks ryanodine receptor calcium-induced calcium release
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000400012
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spelling	oai:scielo:S0716-976020040004000122005-06-02Control of dual isoforms of Ca2+ release channels in muscleRÍOS,EDUARDOZHOU,JINGSONG Excitation-contraction coupling sarcoplasmic reticulum Ca2+ sparks ryanodine receptor calcium-induced calcium release Here we compare excitation-contraction coupling in single muscle cells of frogs and rats. Because amphibians have isoform 3 (or b) of the ryanodine receptor/Ca2+ release channel, in addition to 1 (a), which is also present in the mammal, any extra feature present in the frog may in principle be attributed to isoform 3. Ca2+ release under voltage clamp depolarization has a peak and a steady phase in both taxonomic classes, but the peak is more marked in the frog, where the ratio of amplitudes of the two phases is voltage-dependent. This dependence is a hallmark of CICR. Confocal imaging identified Ca2+ sparks in the frog, but not in the voltage-clamped rat cells. Because Ca2+ sparks involve CICR both observations indicate that the contribution of CICR is minor or null in the mammal. The "couplon" model well accounts for observations in the frog, but assumes a structure that we now know to be valid only for the rat. A revised model is proposed, whereby the isoform 3 channels, located parajunctionally, are activated by CICR and contribute its characteristic global and local features. Several issues regarding the roles of different channels remain open to further study.info:eu-repo/semantics/openAccessSociedad de Biología de ChileBiological Research v.37 n.4 20042004-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000400012en10.4067/S0716-97602004000400012
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Excitation-contraction coupling sarcoplasmic reticulum Ca2+ sparks ryanodine receptor calcium-induced calcium release
spellingShingle	Excitation-contraction coupling sarcoplasmic reticulum Ca2+ sparks ryanodine receptor calcium-induced calcium release RÍOS,EDUARDO ZHOU,JINGSONG Control of dual isoforms of Ca2+ release channels in muscle
description	Here we compare excitation-contraction coupling in single muscle cells of frogs and rats. Because amphibians have isoform 3 (or b) of the ryanodine receptor/Ca2+ release channel, in addition to 1 (a), which is also present in the mammal, any extra feature present in the frog may in principle be attributed to isoform 3. Ca2+ release under voltage clamp depolarization has a peak and a steady phase in both taxonomic classes, but the peak is more marked in the frog, where the ratio of amplitudes of the two phases is voltage-dependent. This dependence is a hallmark of CICR. Confocal imaging identified Ca2+ sparks in the frog, but not in the voltage-clamped rat cells. Because Ca2+ sparks involve CICR both observations indicate that the contribution of CICR is minor or null in the mammal. The "couplon" model well accounts for observations in the frog, but assumes a structure that we now know to be valid only for the rat. A revised model is proposed, whereby the isoform 3 channels, located parajunctionally, are activated by CICR and contribute its characteristic global and local features. Several issues regarding the roles of different channels remain open to further study.
author	RÍOS,EDUARDO ZHOU,JINGSONG
author_facet	RÍOS,EDUARDO ZHOU,JINGSONG
author_sort	RÍOS,EDUARDO
title	Control of dual isoforms of Ca2+ release channels in muscle
title_short	Control of dual isoforms of Ca2+ release channels in muscle
title_full	Control of dual isoforms of Ca2+ release channels in muscle
title_fullStr	Control of dual isoforms of Ca2+ release channels in muscle
title_full_unstemmed	Control of dual isoforms of Ca2+ release channels in muscle
title_sort	control of dual isoforms of ca2+ release channels in muscle
publisher	Sociedad de Biología de Chile
publishDate	2004
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000400012
work_keys_str_mv	AT rioseduardo controlofdualisoformsofca2releasechannelsinmuscle AT zhoujingsong controlofdualisoformsofca2releasechannelsinmuscle
_version_	1718441375381323776

Control of dual isoforms of Ca2+ release channels in muscle

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