Spatial and temporal Ca2+ signalling in articular chondrocytes.
Stimulation of pig articular chondrocytes with either bradykinin, fetal calf serum or the Ca(2+)-ATPase inhibitor thapsigargin induced increases of the cytosolic Ca2+ concentration. By computerized videoimaging, the spatial and temporal aspects of the Ca2+ signal were revealed at single cell level. The cell response depended on Ca2+ release from intracellular stores without significant contribution of Ca2+ influx. A great heterogeneity in the cell population was found with respect to the Ca2+ storage ability. The Ca2+ response initiated in a discrete subcellular region and then spread in a nondecremental fashion to involve the whole cytosol. Such a behaviour was independent of the stimulus applied, thus suggesting a functional heterogeneity of the intracellular Ca2+ stores involved. In the region from which the response started, local Ca2+ spikes were recorded, revealing a spatially restricted pulsatile activity.
D'Andrea
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P
Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Trieste, Italy.
Vittur
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F
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002358:Cartilage, Articular / Q000166:cytology / Q000378:metabolism*; D002417:Cattle; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005312:Fetal Blood; D018715:Microscopy, Video; D010507:Periodicity; D010716:Phosphatidylinositols / Q000378:metabolism; D015398:Signal Transduction; D013552:Swine; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin
D004791:Enzyme Inhibitors; D010716:Phosphatidylinositols; D013729:Terpenes; D019284:Thapsigargin; D000252:Calcium-Transporting ATPases; D001920:Bradykinin; D002118:Calcium