title: Reactive oxygen species are important mediators of taurine release from skeletal muscle cells.
abstract: 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.
authors.affiliation: Danish Institute of Agricultural Sciences, Research Center Foulum, DK-8830, Tjele, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Ørtenblad
authors.forename: Jette Feveile
authors.initials: JF
authors.lastname: Young
authors.forename: Niels
authors.initials: N
authors.lastname: Oksbjerg
authors.forename: Jacob Holm
authors.initials: JH
authors.lastname: Nielsen
authors.forename: Ian Henry
authors.initials: IH
authors.lastname: Lambert
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002084:Butylated Hydroxytoluene / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000378:metabolism; D008555:Melitten / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism*; D009994:Osmolar Concentration; D010741:Phospholipases A / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013552:Swine; D013654:Taurine / Q000378:metabolism*; D014810:Vitamin E / Q000378:metabolism
chemical_list: D000975:Antioxidants; D004791:Enzyme Inhibitors; D008244:Lysophosphatidylcholines; D017382:Reactive Oxygen Species; D014810:Vitamin E; D013654:Taurine; D002084:Butylated Hydroxytoluene; D008555:Melitten; D002784:Cholesterol; D010741:Phospholipases A; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D002118:Calcium