Neuronal input triggers Ca(2+) influx through AMPA receptors and voltage‐gated Ca(2+) channels in oligodendrocytes

Communication between neurons and developing oligodendrocytes (OLs) leading to OL Ca(2+) rise is critical for axon myelination and OL development. Here, we investigate signaling factors and sources of Ca(2+) rise in OLs in the mouse brainstem. Glutamate puff or axon fiber stimulation induces a Ca(2+) rise in pre‐myelinating OLs, which is primarily mediated by Ca(2+)‐permeable AMPA receptors. During glutamate application, inward currents via AMPA receptors and elevated extracellular K(+) caused by increased neuronal activity collectively lead to OL depolarization, triggering Ca(2+) influx via P/Q‐ and L‐type voltage‐gated Ca(2+) (Ca(v)) channels. Thus, glutamate is a key signaling factor in dynamic communication between neurons and OLs that triggers Ca(2+) transients via AMPARs and Ca(v) channels in developing OLs. The results provide a mechanism for OL Ca(2+) dynamics in response to neuronal input, which has implications for OL development and myelination.