Figure 7

BDNF/TrkB signaling regulates NR2B phosphorylation by NRG1 in immature cortical neurons. NRG1-induced activation of its receptor ErbB4 on GABAergic interneurons results in an increased release of GABA. GABA_AR activation, possibly via an autocrine manner in immature neurons leads to release of BDNF, and stimulation of signaling cascades, including TrkB and PLCγ. This leads to the activation of NR2B, providing the machinery required for various neuronal functions before synaptogenesis. Whether NRG1-induced GABA_AR activation occurs in mature cortical neurons via autocrine and/or paracrine manner needs further investigation. In the brain, NRG1 [32] and BDNF [12] are primarily expressed in neurons and astrocytes in vivo.