Current density as routine parameter for description of ionic membrane current: is it always the best option?
Jazyk angličtina Země Anglie, Velká Británie Médium print-electronic
Typ dokumentu časopisecké články, práce podpořená grantem
PubMed
31794822
DOI
10.1016/j.pbiomolbio.2019.11.011
PII: S0079-6107(19)30145-2
Knihovny.cz E-zdroje
- Klíčová slova
- Current density, Current-capacitance correlation, Current-capacitance proportionality, Ionic current, Normalisation by ratio, Rat cardiomyocyte,
- MeSH
- acetylcholin chemie MeSH
- buněčná membrána fyziologie MeSH
- elektrická kapacitance MeSH
- elektrofyziologie MeSH
- genotyp MeSH
- ionty MeSH
- kardiomyocyty účinky léků MeSH
- krysa rodu Rattus MeSH
- membránové potenciály účinky léků MeSH
- myokard MeSH
- potkani Wistar MeSH
- srdeční síně patologie MeSH
- svalové buňky cytologie MeSH
- teoretické modely MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- acetylcholin MeSH
- ionty MeSH
The current density (J) is a parameter routinely used to characterize individual ionic membrane currents. Its evaluation is based on the presumption that the magnitude of whole-cell ionic membrane current (I) is directly proportional to the cell membrane capacitance (C), i.e. I positively and strongly correlates with C and the regression line describing I-C relation intersects the y-axis close to the origin of coordinates. We aimed to prove the presumption in several examples and find whether the conversion of I to J could be always beneficial. I-C relation was analysed in several potassium currents, measured in rat atrial myocytes (in inward rectifier currents, IK1, and both the constitutively active and acetylcholine-induced components of acetylcholine-sensitive current, IK(Ach)CONST and IK(Ach)ACH), and in rat ventricular myocytes (transient outward current Ito). I-C correlation was estimated by the Pearson coefficient (r). A coefficient (k) was newly suggested describing deviation of the regression intercept from zero in currents with considerable r value. Based on mathematical simulations, I was satisfactorily proportional to C when r ≥ 0.6 and k ≤ 0.2 which was fulfilled in IK1 and IK(Ach)ACH (r = 0.84, k = 0.20, and r = 0.61, k = 0.06, respectively). I-C correlation was significantly positive, but weak in IK(Ach)CONST (r = 0.42), and virtually missing in Ito (r = 0.04). The impaired I-C proportionality in IK(Ach)CONST and Ito likely reflects heterogeneity of the channel expression. We conclude that the conversion of I to J should be avoided when I-C proportionality is absent. Otherwise, serious misinterpretation of data may arise.
Citace poskytuje Crossref.org
Cell size induced bias of current density in hypertrophic cardiomyocytes
