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Differences in Effects of Length-Dependent Regulation of Force and Ca(2+) Transient in the Myocardial Trabeculae of the Rat Right Atrium and Ventricle

The comparative differences in the fundamental mechanisms of contractility regulation and calcium handling of atrial and ventricular myocardium remain poorly studied. An isometric force–length protocol was performed for the entire range of preloads in isolated rat right atrial (RA) and ventricular (...

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Autores principales: Lookin, Oleg, Balakin, Alexander, Protsenko, Yuri
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10219166/
https://www.ncbi.nlm.nih.gov/pubmed/37240302
http://dx.doi.org/10.3390/ijms24108960
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author Lookin, Oleg
Balakin, Alexander
Protsenko, Yuri
author_facet Lookin, Oleg
Balakin, Alexander
Protsenko, Yuri
author_sort Lookin, Oleg
collection PubMed
description The comparative differences in the fundamental mechanisms of contractility regulation and calcium handling of atrial and ventricular myocardium remain poorly studied. An isometric force–length protocol was performed for the entire range of preloads in isolated rat right atrial (RA) and ventricular (RV) trabeculae with simultaneous measurements of force (Frank-Starling mechanism) and Ca(2+) transients (CaT). Differences were found between length-dependent effects in RA and RV muscles: (a) the RA muscles were stiffer, faster, and presented with weaker active force than the RV muscles throughout the preload range; (b) the active/passive force—length relationships were almost linear for the RA and RV muscles; (c) the value of the relative length-dependent growth of passive/active mechanical tension did not differ between the RA and RV muscles; (d) the time-to-peak and amplitude of CaT did not differ between the RA and RV muscles; (e) the CaT decay phase was essentially monotonic and almost independent of preload in the RA muscles, but not in the RV muscles. Higher peak tension, prolonged isometric twitch, and CaT in the RV muscle may be the result of higher Ca(2+) buffering by myofilaments. The molecular mechanisms that constitute the Frank-Starling mechanism are common in the rat RA and RV myocardium.
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spelling pubmed-102191662023-05-27 Differences in Effects of Length-Dependent Regulation of Force and Ca(2+) Transient in the Myocardial Trabeculae of the Rat Right Atrium and Ventricle Lookin, Oleg Balakin, Alexander Protsenko, Yuri Int J Mol Sci Article The comparative differences in the fundamental mechanisms of contractility regulation and calcium handling of atrial and ventricular myocardium remain poorly studied. An isometric force–length protocol was performed for the entire range of preloads in isolated rat right atrial (RA) and ventricular (RV) trabeculae with simultaneous measurements of force (Frank-Starling mechanism) and Ca(2+) transients (CaT). Differences were found between length-dependent effects in RA and RV muscles: (a) the RA muscles were stiffer, faster, and presented with weaker active force than the RV muscles throughout the preload range; (b) the active/passive force—length relationships were almost linear for the RA and RV muscles; (c) the value of the relative length-dependent growth of passive/active mechanical tension did not differ between the RA and RV muscles; (d) the time-to-peak and amplitude of CaT did not differ between the RA and RV muscles; (e) the CaT decay phase was essentially monotonic and almost independent of preload in the RA muscles, but not in the RV muscles. Higher peak tension, prolonged isometric twitch, and CaT in the RV muscle may be the result of higher Ca(2+) buffering by myofilaments. The molecular mechanisms that constitute the Frank-Starling mechanism are common in the rat RA and RV myocardium. MDPI 2023-05-18 /pmc/articles/PMC10219166/ /pubmed/37240302 http://dx.doi.org/10.3390/ijms24108960 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Lookin, Oleg
Balakin, Alexander
Protsenko, Yuri
Differences in Effects of Length-Dependent Regulation of Force and Ca(2+) Transient in the Myocardial Trabeculae of the Rat Right Atrium and Ventricle
title Differences in Effects of Length-Dependent Regulation of Force and Ca(2+) Transient in the Myocardial Trabeculae of the Rat Right Atrium and Ventricle
title_full Differences in Effects of Length-Dependent Regulation of Force and Ca(2+) Transient in the Myocardial Trabeculae of the Rat Right Atrium and Ventricle
title_fullStr Differences in Effects of Length-Dependent Regulation of Force and Ca(2+) Transient in the Myocardial Trabeculae of the Rat Right Atrium and Ventricle
title_full_unstemmed Differences in Effects of Length-Dependent Regulation of Force and Ca(2+) Transient in the Myocardial Trabeculae of the Rat Right Atrium and Ventricle
title_short Differences in Effects of Length-Dependent Regulation of Force and Ca(2+) Transient in the Myocardial Trabeculae of the Rat Right Atrium and Ventricle
title_sort differences in effects of length-dependent regulation of force and ca(2+) transient in the myocardial trabeculae of the rat right atrium and ventricle
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10219166/
https://www.ncbi.nlm.nih.gov/pubmed/37240302
http://dx.doi.org/10.3390/ijms24108960
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