Glycine triggers an intracellular calcium influx in oligodendrocyte progenitor cells which is mediated by the activation of both the ionotropic glycine receptor and Na+ - dependent transporters

Using fluo-3 calcium imaging, we demonstrate that glycine induces an increa se in intracellular calcium concentration ([Ca2+](i)) in cortical oligodend rocyte progenitor (OP) cells. This effect results from a calcium entry thro ugh voltage-gated calcium channels (VGCC), as it is observed only in OP cel ls expressing such channels, and it is abolished either by removal of calci um from the extracellular medium or by application of an L-type VGCC blocke r. Glycine-triggered Ca2+ influx in OP cells actually results from an initi al depolarization that is the consequence of the activation of both the ion otropic glycine receptor (GlyR) and Na+-dependent transporters, most probab ly the glycine transporters 1 (GLYT1) and/or 2 (GLYT2) which are colocalize d in these cells. Through this GlyR- and transporter-mediated effect on OP intrcellular calcium concentration [Ca2+](i), glycine released by neurons m ay, as well as other neurotransmitters, serve as a signal between neurons a nd OP during development.