A mathematical model of Ca2+ dynamics in rat mesenteric smooth muscle cell: Agonist and NO stimulation

Adam Kapela, Anastasios Bezerianos, Nikolaos M. Tsoukias

Research output: Contribution to journalArticle

Abstract

A mathematical model of calcium dynamics in vascular smooth muscle cell (SMC) was developed based on data mostly from rat mesenteric arterioles. The model focuses on (a) the plasma membrane electrophysiology; (b) Ca2+ uptake and release from the sarcoplasmic reticulum (SR); (c) cytosolic balance of Ca2+, Na+, K+, and Cl- ions; and (d) IP3 and cGMP formation in response to norepinephrine (NE) and nitric oxide (NO) stimulation. Stimulation with NE induced membrane depolarization and an intracellular Ca2+ ([Ca2+]i) transient followed by a plateau. The plateau concentrations were mostly determined by the activation of voltage-operated Ca2+ channels. NE causes a greater increase in [Ca2+]i than stimulation with KCl to equivalent depolarization. Model simulations suggest that the effect of [Na+]i accumulation on the Na+/Ca2+ exchanger (NCX) can potentially account for this difference. Elevation of [Ca2+]i within a concentration window (150-300 nM) by NE or KCl initiated [Ca2+]i oscillations with a concentration-dependent period. The oscillations were generated by the nonlinear dynamics of Ca2+ release and refilling in the SR. NO repolarized the NE-stimulated SMC and restored low [Ca2+]i mainly through its effect on Ca2+-activated K+ channels. Under certain conditions, Na+-K+-ATPase inhibition can result in the elevation of [Na+]i and the reversal of NCX, increasing resting cytosolic and SR Ca2+ content, as well as reactivity to NE. Blockade of the NCX's reverse mode could eliminate these effects. We conclude that the integration of the selected cellular components yields a mathematical model that reproduces, satisfactorily, some of the established features of SMC physiology. Simulations suggest a potential role of intracellular Na+ in modulating Ca2+ dynamics and provide insights into the mechanisms of SMC constriction, relaxation, and the phenomenon of vasomotion. The model will provide the basis for the development of multi-cellular mathematical models that will investigate microcirculatory function in health and disease.

Original languageEnglish (US)
Pages (from-to)238-260
Number of pages23
JournalJournal of Theoretical Biology
Volume253
Issue number2
DOIs
StatePublished - Jul 21 2008

Keywords

  • Ion channels
  • Membrane potential
  • Microcirculation
  • Vascular tone

ASJC Scopus subject areas

  • Statistics and Probability
  • Modeling and Simulation
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Agricultural and Biological Sciences(all)
  • Applied Mathematics

Fingerprint Dive into the research topics of 'A mathematical model of Ca<sup>2+</sup> dynamics in rat mesenteric smooth muscle cell: Agonist and NO stimulation'. Together they form a unique fingerprint.

  • Cite this