Reactive oxygen species are important mediators of taurine release from skeletal muscle cells

• Published in: American Journal of Physiology: Cell Physiology 2003-06, Vol.284 (6), p.C1362-C1373
• Main Authors: Ortenblad, Niels, Young, Jette Feveile, Oksbjerg, Niels, Nielsen, Jacob Holm, Lambert, Ian Henry
• Format: Article
• Language: English
• Subjects: 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid - metabolism; Animals; Antioxidants - metabolism; Butylated Hydroxytoluene - metabolism; Calcium - metabolism; Cells, Cultured; Cholesterol - metabolism; Enzyme Inhibitors - metabolism; Humans; Hypoxia - metabolism; Lysophosphatidylcholines - metabolism; Melitten - metabolism; Muscle, Skeletal - cytology; Muscle, Skeletal - metabolism; Osmolar Concentration; Phospholipases A - metabolism; Reactive Oxygen Species - metabolism; Satellite Cells, Skeletal Muscle - cytology; Satellite Cells, Skeletal Muscle - metabolism; Signal Transduction - physiology; Swine; Taurine - metabolism; Vitamin E - metabolism
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00287.2002

1  Danish Institute of Agricultural Sciences, Research Center Foulum, DK-8830, Tjele; and 2  The August Krogh Institute, Biochemical Department, DK-2100 Copenhagen Ø, Denmark The present study illustrates elements of the signal cascades involved in the activation of taurine efflux pathways in myotubes derived from skeletal muscle cells. Exposing primary skeletal muscle cells, loaded with 14 C-taurine, to 1 ) hypotonic media, 2 ) the phospholipase A 2 (PLA 2 ) activator melittin, 3 ) anoxia, or 4 ) lysophosphatidyl choline (LPC) causes an increase in 14 C-taurine release and a concomitant production of reactive oxygen species (ROS). The antioxidants butulated hydroxy toluene and vitamin E inhibit the taurine efflux after cell swelling, anoxia, and addition of LPC. The muscle cells possess two separate taurine efflux pathways, i.e., a swelling- and melittin-induced pathway that requires 5-lipoxygenase activity for activation and a LPC-induced pathway. The two pathways are distinguished by their opposing sensitivity toward the anion channel blocker DIDS and cholesterol. These data provide evidence for PLA 2 products and ROS as key mediators of the signal cascade leading to taurine efflux in muscle. C2C12; calcium; cell volume regulation; 5-lipoxygenase; melittin; anoxia; secretory phospholipase A 2