Enhanced calcium release at specialised surface sites compensates for reduced t-tubule density in neonatal sheep atrial myocytes.

Autor: Smith CER; Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.14 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom., Pinali C; Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.14 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom., Eisner DA; Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.14 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom., Trafford AW; Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.14 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom., Dibb KM; Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.14 Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, United Kingdom. Electronic address: katharine.dibb@manchester.ac.uk.
Jazyk: angličtina
Zdroj: Journal of molecular and cellular cardiology [J Mol Cell Cardiol] 2022 Dec; Vol. 173, pp. 61-70. Date of Electronic Publication: 2022 Aug 28.
DOI: 10.1016/j.yjmcc.2022.08.360
Abstrakt: Cardiac myocytes rely on transverse (t)-tubules to facilitate a rapid rise in calcium throughout the cell. However, despite their importance in triggering synchronous Ca 2+ release, t-tubules are highly labile structures. They develop postnatally, increase in density during exercise training and are lost in diseases such as heart failure (HF). In the majority of settings, an absence of t-tubules decreases function. Here we show that despite reduced t-tubule density due to immature t-tubules, the newborn atrium is highly specialised to maintain Ca 2+ release. To compensate for fewer t-tubules triggering a central rise in Ca 2+ , Ca 2+ release at sites on the cell surface is enhanced in the newborn, exceeding that at all Ca 2+ release sites in the adult. Using electron and super resolution microscopy to investigate myocyte ultrastructure, we found that newborn atrial cells had enlarged surface sarcoplasmic reticulum and larger, more closely spaced surface and central ryanodine receptor clusters. We suggest that these adaptations mediate enhanced Ca 2+ release at the sarcolemma and aid propagation to compensate for reduced t-tubule density in the neonatal atrium.
(Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: