Differential regulation of NRG1 type expression in cultured neurons and astrocytes by KCl treatment. Total RNAs were isolated from control or KCl (50 mm, 6 h)-treated cortical neurons (A–F, indicated ages) and astrocytes (G, H), and subjected to RT-qPCR. NRG1 types were first normalized by β-actin, whose levels were revealed in the same reactions and then normalized by control. **p < 0.01.