Loading…

A fundamental evaluation of the electrical properties and function of cardiac transverse tubules

This work discusses active and passive electrical properties of transverse (T-)tubules in ventricular cardiomyocytes to understand the physiological roles of T-tubules. T-tubules are invaginations of the lateral membrane that provide a large surface for calcium-handling proteins to facilitate sarcom...

Full description

Saved in:
Bibliographic Details
Published in:Biochimica et biophysica acta. Molecular cell research 2020-03, Vol.1867 (3), p.118502-118502, Article 118502
Main Authors: Vermij, S.H., Abriel, H., Kucera, J.P.
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This work discusses active and passive electrical properties of transverse (T-)tubules in ventricular cardiomyocytes to understand the physiological roles of T-tubules. T-tubules are invaginations of the lateral membrane that provide a large surface for calcium-handling proteins to facilitate sarcomere shortening. Higher heart rates correlate with higher T-tubular densities in mammalian ventricular cardiomyocytes. We assess ion dynamics in T-tubules and the effects of sodium current in T-tubules on the extracellular potential, which leads to a partial reduction of the sodium current in deep segments of a T-tubule. We moreover reflect on the impact of T-tubules on macroscopic conduction velocity, integrating fundamental principles of action potential propagation and conduction. We also theoretically assess how the conduction velocity is affected by different T-tubular sodium current densities. Lastly, we critically assess literature on ion channel expression to determine whether action potentials can be initiated in T-tubules. •Transverse (T-)tubules facilitate excitation-contraction coupling in cardiomyocytes•T-tubular membrane deep in the cell depolarizes later than surface membrane•Sodium channel expression in T-tubules remains controversial•Large T-tubular sodium currents would induce a negative intratubular potential•T-tubules probably slow down macroscopic conduction
ISSN:0167-4889
1879-2596
DOI:10.1016/j.bbamcr.2019.06.016