The development of L-type Ca2+ current mediated alternans does not depend on the restitution slope in canine ventricular myocardium

Abstract Cardiac alternans have crucial importance in the onset of ventricular fibrillation. The early explanation for alternans development was the voltage-driven mechanism, where the action potential (AP) restitution steepness was considered as crucial determining factor. Recent results suggest th...

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Autores principales:	Noémi Tóth, Jozefina Szlovák, Zsófia Kohajda, Gergő Bitay, Roland Veress, Balázs Horváth, Julius Gy. Papp, András Varró, Norbert Nagy
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/77bd7883115c4f689d1c006834402ec3
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spelling	oai:doaj.org-article:77bd7883115c4f689d1c006834402ec32021-12-02T16:46:35ZThe development of L-type Ca2+ current mediated alternans does not depend on the restitution slope in canine ventricular myocardium10.1038/s41598-021-95299-72045-2322https://doaj.org/article/77bd7883115c4f689d1c006834402ec32021-08-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-95299-7https://doaj.org/toc/2045-2322Abstract Cardiac alternans have crucial importance in the onset of ventricular fibrillation. The early explanation for alternans development was the voltage-driven mechanism, where the action potential (AP) restitution steepness was considered as crucial determining factor. Recent results suggest that restitution slope is an inadequate predictor for alternans development, but several studies still claim the role of membrane potential as underlying mechanism of alternans. These controversial data indicate that the relationship of restitution and alternans development is not completely understood. APs were measured by conventional microelectrode technique from canine right ventricular papillary muscles. Ionic currents combined with fluorescent measurements were recorded by patch-clamp technique. APs combined with fluorescent measurements were monitored by sharp microelectrodes. Rapid pacing evoked restitution-independent AP duration (APD) alternans. When non-alternating AP voltage command was used, Ca2+ i-transient (CaT) alternans were not observed. When alternating rectangular voltage pulses were applied, CaT alternans were proportional to ICaL amplitude alternans. Selective ICaL inhibition did not influence the fast phase of APD restitution. In this study we found that ICaL has minor contribution in shaping the fast phase of restitution curve suggesting that ICaL—if it plays important role in the alternans mechanism—could be an additional factor that attenuates the reliability of APD restitution slope to predict alternans.Noémi TóthJozefina SzlovákZsófia KohajdaGergő BitayRoland VeressBalázs HorváthJulius Gy. PappAndrás VarróNorbert NagyNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-12 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Noémi Tóth Jozefina Szlovák Zsófia Kohajda Gergő Bitay Roland Veress Balázs Horváth Julius Gy. Papp András Varró Norbert Nagy The development of L-type Ca2+ current mediated alternans does not depend on the restitution slope in canine ventricular myocardium
description	Abstract Cardiac alternans have crucial importance in the onset of ventricular fibrillation. The early explanation for alternans development was the voltage-driven mechanism, where the action potential (AP) restitution steepness was considered as crucial determining factor. Recent results suggest that restitution slope is an inadequate predictor for alternans development, but several studies still claim the role of membrane potential as underlying mechanism of alternans. These controversial data indicate that the relationship of restitution and alternans development is not completely understood. APs were measured by conventional microelectrode technique from canine right ventricular papillary muscles. Ionic currents combined with fluorescent measurements were recorded by patch-clamp technique. APs combined with fluorescent measurements were monitored by sharp microelectrodes. Rapid pacing evoked restitution-independent AP duration (APD) alternans. When non-alternating AP voltage command was used, Ca2+ i-transient (CaT) alternans were not observed. When alternating rectangular voltage pulses were applied, CaT alternans were proportional to ICaL amplitude alternans. Selective ICaL inhibition did not influence the fast phase of APD restitution. In this study we found that ICaL has minor contribution in shaping the fast phase of restitution curve suggesting that ICaL—if it plays important role in the alternans mechanism—could be an additional factor that attenuates the reliability of APD restitution slope to predict alternans.
format	article
author	Noémi Tóth Jozefina Szlovák Zsófia Kohajda Gergő Bitay Roland Veress Balázs Horváth Julius Gy. Papp András Varró Norbert Nagy
author_facet	Noémi Tóth Jozefina Szlovák Zsófia Kohajda Gergő Bitay Roland Veress Balázs Horváth Julius Gy. Papp András Varró Norbert Nagy
author_sort	Noémi Tóth
title	The development of L-type Ca2+ current mediated alternans does not depend on the restitution slope in canine ventricular myocardium
title_short	The development of L-type Ca2+ current mediated alternans does not depend on the restitution slope in canine ventricular myocardium
title_full	The development of L-type Ca2+ current mediated alternans does not depend on the restitution slope in canine ventricular myocardium
title_fullStr	The development of L-type Ca2+ current mediated alternans does not depend on the restitution slope in canine ventricular myocardium
title_full_unstemmed	The development of L-type Ca2+ current mediated alternans does not depend on the restitution slope in canine ventricular myocardium
title_sort	development of l-type ca2+ current mediated alternans does not depend on the restitution slope in canine ventricular myocardium
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/77bd7883115c4f689d1c006834402ec3
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The development of L-type Ca2+ current mediated alternans does not depend on the restitution slope in canine ventricular myocardium

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