title: Heterogeneity and weak coupling may explain the synchronization characteristics of cells in the arterial wall.
abstract: Vascular smooth muscle cells (SMCs) exhibit different types of calcium dynamics. Static vascular tone is associated with unsynchronized calcium waves and the developed force depends on the number of recruited cells. Global calcium transients synchronized among a large number of cells cause rhythmic development of force known as vasomotion. We present experimental data showing a considerable heterogeneity in cellular calcium dynamics in the vascular wall. In stimulated vessels, some SMCs remain quiescent, whereas others display waves of variable frequency. At the onset of vasomotion, all SMCs are enrolled into synchronized oscillation. Simulations of coupled SMCs show that the experimentally observed cellular recruitment, the presence of quiescent cells and the variation in oscillation frequency may arise if the cell population is phenotypically heterogeneous. In this case, quiescent cells can be entrained at the onset of vasomotion by the collective driving force from the synchronized oscillations in the membrane potential of the surrounding cells. Partial synchronization arises with an increase in the concentration of cyclic guanosine monophosphate, but in a heterogeneous cell population complete synchronization also requires a high-conductance pathway that provides strong coupling between the cells.
authors.affiliation: The Danish National Research Foundation Centre for Cardiac Arrhythmias, Department of Biomedical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark. jcbrings@mfi.ku.dk
authors.forename: Jens Christian Brings
authors.initials: JC
authors.lastname: Jacobsen
authors.forename: Christian
authors.initials: C
authors.lastname: Aalkjaer
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Matchkov
authors.forename: Holger
authors.initials: H
authors.lastname: Nilsson
authors.forename: Jacob J
authors.initials: JJ
authors.lastname: Freiberg
authors.forename: Niels-Henrik
authors.initials: NH
authors.lastname: Holstein-Rathlou
mesh_terms: D000818:Animals; D001158:Arteries / Q000473:pathology*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D003600:Cytosol / Q000378:metabolism; D017629:Gap Junctions; D006157:Guanosine Monophosphate / Q000737:chemistry; D008564:Membrane Potentials; D008954:Models, Biological; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000166:cytology*; D009991:Oscillometry; D051381:Rats; D017208:Rats, Wistar
chemical_list: D006157:Guanosine Monophosphate; D002118:Calcium