A fundamental evaluation of the electrical properties and function of cardiac transverse tubules
| Autor: | Jan P. Kucera, Sarah H. Vermij, Hugues Abriel |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Sarcomeres
0301 basic medicine Materials science Action potential Heart Ventricles Action Potentials 030204 cardiovascular system & hematology Sarcomere Nerve conduction velocity 03 medical and health sciences Sarcolemma 0302 clinical medicine Cardiac conduction Humans Myocyte Myocytes Cardiac Calcium Signaling Molecular Biology Ion channel Sodium channel Sodium Cell Biology Thermal conduction Sarcoplasmic Reticulum 030104 developmental biology Biophysics Electromagnetic Phenomena |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Molecular Cell Research. 1867:118502 |
| ISSN: | 0167-4889 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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