Electrophysiological modelling of pulmonary artery smooth muscle cells in the rabbits-Special consideration to the generation of hypoxic pulmonary vasoconstriction

Chae Young Cha, Kee Hyun Earm, Jae Boum Youm, Eun Bok Baek, Sung Joon Kim, Yung E. Earm

Research output: Contribution to journalReview articlepeer-review

8 Scopus citations

Abstract

In vascular smooth muscle cells, it has been suggested that membrane potential is an important component that initiates contraction. We developed a mathematical model to elucidate the quantitative contributions of major ion currents [a voltage-gated L-type Ca2+ current (ICaL), a voltage-sensitive K+ current (IKV), a Ca2+-activated K+ current (IKCa) and a nonselective cation current (INSC)] to membrane potential. In order to typify the diverse nature of pulmonary artery smooth muscle cells (PASMCs), we introduced parameters that are not fixed (variable parameters). The population of cells with different parameters was constructed and the cells that have the electrophysiological properties of PASMCs were selected. The contributions of each membrane current were investigated by sensitivity analysis and modification of the current parameters. Consequently, IKV and INSC were found to be the most important currents that affect the membrane potential. The occurrence of depolarisation in hypoxic pulmonary vasoconstriction (HPV) was also examined. In hypoxia, IKV and IKCa were reduced, but the consequent depolarisation in simulation was not enough to initiate contractions. If we add an increase of INSC (2.5-fold), the calculated membrane potential was enough to induce contraction. From the results, we conclude that the balance of various ion channel activities determines the resting membrane potential of PASMCs and our model was successful in explaining the depolarisation in HPV. Therefore, this model can be a powerful tool to investigate the various electrical properties of PASMCs in both normal and pathological conditions.

Original languageEnglish
Pages (from-to)399-420
Number of pages22
JournalProgress in Biophysics and Molecular Biology
Volume96
Issue number1-3
DOIs
StatePublished - Jan 2008

Keywords

  • Hypoxic pulmonary vasoconstriction
  • Mathematical model
  • Membrane potential

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