title: Intracellular calcium changes in rat aortic smooth muscle cells in response to fluid flow.
abstract: Vascular smooth muscle cells (VSM) are normally exposed to transmural fluid flow shear stresses, and after vascular injury, blood flow shear stresses are imposed upon them. Since Ca2+ is a ubiquitous intracellular signaling molecule, we examined the effects of fluid flow on intracellular Ca2+ concentration in rat aortic smooth muscle cells to assess VSM responsiveness to shear stress. Cells loaded with fura 2 were exposed to steady flow shear stress levels of 0.5-10.0 dyn/cm2 in a parallel-plate flow chamber. The percentage of cells displaying a rise in cytosolic Ca2+ ion concentration ([Ca2+]i) increased in response to increasing flow, but there was no effect of flow on the ([Ca2+]i) amplitude of responding cells. Addition of Gd3+ (10 microM) or thapsigargin (50 nM) significantly reduced the percentage of cells responding and the response amplitude, suggesting that influx of Ca2+ through ion channels and release from intracellular stores contribute to the rise in ([Ca2+]i) in response to flow. The addition of nifedipine (1 or 10 microM) or ryanodine (10 microM) also significantly reduced the response amplitude, further defining the role of ion channels and intracellular stores in the Ca2+ response.
authors.affiliation: Department of Chemical Engineering, The Pennsylvania State University, University Park 16802, USA.
authors.forename: Ritu
authors.initials: R
authors.lastname: Sharma
authors.forename: Clare E
authors.initials: CE
authors.lastname: Yellowley
authors.forename: Mete
authors.initials: M
authors.lastname: Civelek
authors.forename: Kristy
authors.initials: K
authors.lastname: Ainslie
authors.forename: Louis
authors.initials: L
authors.lastname: Hodgson
authors.forename: John M
authors.initials: JM
authors.lastname: Tarbell
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Donahue
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D018056:Hemorheology; D066298:In Vitro Techniques; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012433:Ryanodine / Q000494:pharmacology; D012680:Sensitivity and Specificity; D033081:Shear Strength; D013314:Stress, Mechanical; D019284:Thapsigargin / Q000494:pharmacology
chemical_list: D012433:Ryanodine; D019284:Thapsigargin; D002118:Calcium