Increase in cytosolic Ca2+ induced by elevation of extracellular Ca2+ in skeletal myogenic cells

• Published in: American Journal of Physiology: Cell Physiology 2003-04, Vol.284 (4), p.C969-C976
• Main Authors: Naro, Fabio, De Arcangelis, Vania, Coletti, Dario, Molinaro, Mario, Zani, Bianca, Vassanelli, Stefano, Reggiani, Carlo, Teti, Anna, Adamo, Sergio
• Format: Article
• Language: English
• Subjects: Animals; Arginine Vasopressin - pharmacology; Calcium - metabolism; Cell Line; Cytosol - metabolism; Extracellular Space - metabolism; Intracellular Membranes - metabolism; Membrane Potentials - physiology; Muscle Development - physiology; Muscle, Skeletal - cytology; Muscle, Skeletal - physiology; Myoblasts - physiology; Osmolar Concentration; Phosphorylation; Rats
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00237.2002

1  Dipartimento di Istologia ed Embriologia Medica, Università "La Sapienza," 00161 Rome; 2  Dipartimento di Medicina Sperimentale, Università di L'Aquila, 60710 L'Aquila; and 3  Dipartimento di Anatomia e Fisiologia, Università di Padova, 35131 Padua, Italy Cytoplasmic Ca 2+ concentration ([Ca 2+ ] i ) variation is a key event in myoblast differentiation, but the mechanism by which it occurs is still debated. Here we show that increases of extracellular Ca 2+ concentration ([Ca 2+ ] o ) produced membrane hyperpolarization and a concentration-dependent increase of [Ca 2+ ] i due to Ca 2+ influx across the plasma membrane. Responses were not related to inositol phosphate turnover and Ca 2+ -sensing receptor. [Ca 2+ ] o -induced [Ca 2+ ] i increase was inhibited by Ca 2+ channel inhibitors and appeared to be modulated by several kinase activities. [Ca 2+ ] i increase was potentiated by depletion of intracellular Ca 2+ stores and depressed by inactivation of the Na + /Ca 2+ exchanger. The response to arginine vasopressin (AVP), which induces inositol 1,4,5-trisphosphate-dependent [Ca 2+ ] i increase in L6-C5 cells, was not modified by high [Ca 2+ ] o . On the contrary, AVP potentiated the [Ca 2+ ] i increase in the presence of elevated [Ca 2+ ] o . Other clones of the L6 line as well as the rhabdomyosarcoma RD cell line and the satellite cell-derived C2-C12 line expressed similar responses to high [Ca 2+ ] o , and the amplitude of the responses was correlated with the myogenic potential of the cells. calcium; myogenesis; calcium channels; sodium-calcium exchanger