A model of the guinea-pig ventricular cardiac myocyte incorporating a transverse-axial tubular system
Jazyk angličtina Země Anglie, Velká Británie Médium print-electronic
Typ dokumentu časopisecké články, práce podpořená grantem, přehledy
Grantová podpora
British Heart Foundation - United Kingdom
Wellcome Trust - United Kingdom
PubMed
17888503
DOI
10.1016/j.pbiomolbio.2007.07.022
PII: S0079-6107(07)00062-4
Knihovny.cz E-zdroje
- MeSH
- kardiomyocyty fyziologie MeSH
- modely kardiovaskulární * MeSH
- morčata MeSH
- sarkoplazmatické retikulum fyziologie MeSH
- srdce - funkce komor * MeSH
- srdeční komory cytologie MeSH
- zvířata MeSH
- Check Tag
- morčata MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
A model of the guinea-pig cardiac ventricular myocyte has been developed that includes a representation of the transverse-axial tubular system (TATS), including heterogeneous distribution of ion flux pathways between the surface and tubular membranes. The model reproduces frequency-dependent changes of action potential shape and intracellular ion concentrations and can replicate experimental data showing ion diffusion between the tubular lumen and external solution in guinea-pig myocytes. The model is stable at rest and during activity and returns to rested state after perturbation. Theoretical analysis and model simulations show that, due to tight electrical coupling, tubular and surface membranes behave as a homogeneous whole during voltage and current clamp (maximum difference 0.9 mV at peak tubular INa of -38 nA). However, during action potentials, restricted diffusion and ionic currents in TATS cause depletion of tubular Ca2+ and accumulation of tubular K+ (up to -19.8% and +3.4%, respectively, of bulk extracellular values, at 6 Hz). These changes, in turn, decrease ion fluxes across the TATS membrane and decrease sarcoplasmic reticulum (SR) Ca2+ load. Thus, the TATS plays a potentially important role in modulating the function of guinea-pig ventricular myocyte in physiological conditions.
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