title: Spontaneous oscillation and mechanically induced calcium waves in chondrocytes.
abstract: The characteristics of spontaneous calcium (Ca(2+)) oscillation and mechanically induced Ca(2+) waves in articular chondrocytes were studied. In some, but not all, chondrocytes in sliced cartilage and primary cultures, we observed spontaneous oscillation of intracellular Ca(2+) that never spread to adjacent cells. In contrast, a mechanical stimulus to a single cell by touching with a glass rod induced an increase of intracellular Ca(2+) that spread to neighboring cells in a wave-like manner, even though there was no physical contact between the cells. This indicated the release of some paracrine factor from the mechanically stimulated cells. Application of ultrasonic vibration also induced an oscillation of intracellular Ca(2+). The application of a uridine 5'-triphosphate (UTP), UTP, induced a transient increase in intracellular Ca(2+) and the release of adenosine 5'-triphosphate (ATP) in cultured chondrocytes. A P2 receptor antagonist (suramin) and blockers of Cl(-) channels, niflumic acid and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), reduced the UTP-induced ATP release. The results indicated that Cl(-) channels were involved in the extracellular release of ATP following mechanical or P2Y receptor stimulation. Thus, ATP stimulation of P2Y receptors elicits an increase in intracellular Ca(2+), triggering further release of ATP from adjacent cells, thereby expanding the Ca(2+) wave in chondrocytes.
authors.affiliation: Department of Orthopaedics, Faculty of Medicine, Shimane University, Izumo-shi, Shimane, Japan. tk@med.shimane-u.ac.jp
authors.forename: Taisuke
authors.initials: T
authors.lastname: Kono
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Nishikori
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kataoka
authors.forename: Yuji
authors.initials: Y
authors.lastname: Uchio
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
authors.forename: Koh-ichi
authors.initials: K
authors.lastname: Enomoto
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002358:Cartilage, Articular / Q000166:cytology; D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects / Q000502:physiology*; D005456:Fluorescent Dyes; D016257:Fura-2; D009544:Niflumic Acid / Q000494:pharmacology; D058919:Purinergic P2 Receptor Antagonists; D011817:Rabbits; D013314:Stress, Mechanical; D013498:Suramin / Q000494:pharmacology; D014465:Ultrasonics; D014544:Uridine Triphosphate / Q000494:pharmacology
chemical_list: D005456:Fluorescent Dyes; D058919:Purinergic P2 Receptor Antagonists; D009544:Niflumic Acid; D013498:Suramin; D000255:Adenosine Triphosphate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D002118:Calcium; D016257:Fura-2; D014544:Uridine Triphosphate