title: Numerical analysis of the effect of T-tubule location on calcium transient in ventricular myocytes.
abstract: Intracellular calcium (Ca2+) signaling in cardiac myocytes is vital for proper functioning of the heart. Understanding the intracellular Ca2+ dynamics would give an insight into the functions of normal and diseased hearts. In the current study, spatiotemporal Ca2+ dynamics is investigated in ventricular myocytes by considering Ca2+ release and re-uptake via sarcolemma and transverse tubules (T-tubules), Ca2+ diffusion and buffering in the cytosol, and the blockade of Ca2+ activities associated with the sarcoplasmic reticulum. This study is carried out using a three dimensional (3D) geometric model of a branch of T-tubule extracted from the electron microscopy (EM) images of a partial ventricular myocyte. Mathematical modeling is done by using a system of partial differential equations involving Ca2+, buffers, and membrane channels. Numerical simulation results suggest that a lack of T-tubule structure at the vicinity of the cell surface could increase the peak time of Ca2+ concentration in myocytes. The results also show that T-tubules and mobile buffers play an important role in the regulation of Ca2+ transient in ventricular myocytes.
authors.affiliation: Department of Computer Science, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, U.S.A.
authors.forename: Uduak Z
authors.initials: UZ
authors.lastname: George
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Zeyun
authors.initials: Z
authors.lastname: Yu
mesh_terms: D000465:Algorithms; D000818:Animals; D002021:Buffers; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D003198:Computer Simulation; D003600:Cytosol / Q000378:metabolism; D004058:Diffusion; D020342:Finite Element Analysis; D006352:Heart Ventricles / Q000166:cytology / Q000473:pathology*; D006801:Humans; D008854:Microscopy, Electron; D008962:Models, Theoretical; D032383:Myocytes, Cardiac / Q000166:cytology*; D018408:Patch-Clamp Techniques; D012508:Sarcolemma / Q000473:pathology; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D013997:Time Factors
chemical_list: D002021:Buffers; D002118:Calcium
keywords: Cardiac myocytes; calcium dynamics; finite element method; numerical analysis; reaction-diffusion equations