title: Mechanical stimulation induces intercellular calcium signaling in bovine aortic endothelial cells.
abstract: To study the mechanism by which endothelial cells respond to mechanical forces, we used digital fluorescence microscopy to measure changes in intracellular Ca2+ concentration ([Ca2+]i) in primary cultures of bovine aortic endothelial cells in response to mechanical stimulation. Before stimulation, [Ca2+]i was stable (approximately 50-75 nM). When an individual cell within the monolayer was mechanically stimulated with a microprobe, [Ca2+]i increased in the stimulated cell and spread in the form of a wave from the site of contact to the cell edges. After a delay of approximately 1 s, nonstimulated adjacent cells showed a similar spreading rise in [Ca2+]i. This outwardly radiating [Ca2+]i wave involved progressively more distal cells to a radius of 4-6 cells. The time delay before the wave appeared in adjacent cells increased, and peak [Ca2+]i in each cell decreased with distance from the stimulated cell. In the absence of extracellular Ca2+, there was no increase in [Ca2+]i in the stimulated cell, yet a wave of increased [Ca2+]i occurred in neighboring cells as if communicated from the stimulated cell. These results indicate that endothelial cell mechanosensitivity results in increases in [Ca2+]i and that the temporospatial dynamics of intercellular Ca2+ signaling are mediated by a diffusible substance other than Ca2+.
authors.affiliation: Department of Medicine, School of Medicine, University of California, Los Angeles 90024.
authors.forename: L L
authors.initials: LL
authors.lastname: Demer
authors.forename: C M
authors.initials: CM
authors.lastname: Wortham
authors.forename: E R
authors.initials: ER
authors.lastname: Dirksen
authors.forename: M J
authors.initials: MJ
authors.lastname: Sanderson
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D002417:Cattle; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D005110:Extracellular Space / Q000378:metabolism; D008858:Microscopy, Phase-Contrast; D009994:Osmolar Concentration; D010812:Physical Stimulation; D011930:Reaction Time; D015398:Signal Transduction
chemical_list: D002118:Calcium