title: The role of Na+/K+-ATPase during chick skeletal myogenesis.
abstract: The formation of a vertebrate skeletal muscle fiber involves a series of sequential and interdependent events that occurs during embryogenesis. One of these events is myoblast fusion which has been widely studied, yet not completely understood. It was previously shown that during myoblast fusion there is an increase in the expression of Na+/K+-ATPase. This fact prompted us to search for a role of the enzyme during chick in vitro skeletal myogenesis. Chick myogenic cells were treated with the Na+/K+-ATPase inhibitor ouabain in four different concentrations (0.01-10 μM) and analyzed. Our results show that 0.01, 0.1 and 1 μM ouabain did not induce changes in cell viability, whereas 10 μM induced a 45% decrease. We also observed a reduction in the number and thickness of multinucleated myotubes and a decrease in the number of myoblasts after 10 μM ouabain treatment. We tested the involvement of MEK-ERK and p38 signaling pathways in the ouabain-induced effects during myogenesis, since both pathways have been associated with Na+/K+-ATPase. The MEK-ERK inhibitor U0126 alone did not alter cell viability and did not change ouabain effect. The p38 inhibitor SB202190 alone or together with 10 μM ouabain did not alter cell viability. Our results show that the 10 μM ouabain effects in myofiber formation do not involve the MEK-ERK or the p38 signaling pathways, and therefore are probably related to the pump activity function of the Na+/K+-ATPase.
authors.affiliation: Laboratório de Diferenciação Muscular e Citoesqueleto, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Taissa Neustadt
authors.initials: TN
authors.lastname: Oliveira
authors.affiliation: Laboratório de Diferenciação Muscular e Citoesqueleto, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Ana Claudia
authors.initials: AC
authors.lastname: Possidonio
authors.affiliation: Laboratório de Diferenciação Muscular e Citoesqueleto, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Carolina Pontes
authors.initials: CP
authors.lastname: Soares
authors.affiliation: Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Ayres
authors.affiliation: Laboratório de Diferenciação Muscular e Citoesqueleto, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Manoel Luis
authors.initials: ML
authors.lastname: Costa
authors.affiliation: Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Luis Eduardo Menezes
authors.initials: LE
authors.lastname: Quintas
authors.affiliation: Laboratório de Diferenciação Muscular e Citoesqueleto, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Mermelstein
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D024510:Muscle Development; D032446:Myoblasts / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase