Analysis of Ca(2+) signaling mechanisms - our experience on the intercellular communication in muscle remodeling.

The aim of this study was to evaluate cell diversity by considering how Ca(2+) signaling has been adapted in skeletal muscle cell function. We characterized single C2C12 myoblasts through intracellular Ca(2+) signaling kinetics after exposure to specific drugs and calcium blockers using fast fluorescence microspectrofluorimetry followed by ATP effect analysis, which confirmed the expression of functional purinergic adenosine and P2 receptors. Further, we found that glutamate sensitivity of C2C12 cells was mediated by ionotropic glutamate receptors; on the other hand, most cells were responsive to cyclopiazonic acid, which inhibits the sarco-endoplasmic reticulum Ca(2+)-ATPase pump. These results suggest that C2C12 cells possess functional L- and P/Q-type voltage-operated Ca2+ channels, ryanodine receptors and functional sarcoplasmic reticulum Ca2+ stores (typical for muscle cells), adenosine and P2 purinergic receptors, as well as ionotropic glutamate receptors. The evaluation of intracellular Ca2+ signaling is a promising approach towards a better understanding and control of the physiopathological properties of myogenic cells that could be used as a predictive factor in the selection of optimal cells for scaffold recellularization or for tissue engineered constructs used in stem cell therapy.