Neurotrophic tyrosine kinase receptor type 2 (NTRK2) is also known as BDNF/NT-3 growth factors receptor, Tropomyosin-related kinase B (TRKB) and TrkB tyrosine kinase, which belongs to the protein kinase superfamily or Tyr protein kinase family. Insulin receptor subfamily. NTRK2 / TrkB contains two Ig-like C2-type (immunoglobulin-like) domains, two LRR (leucine-rich) repeats, one LRRCT domain, one LRRNT domain, one protein kinase domain. NTRK2 / Trk-B is expressed in the central and peripheral nervous system. The catalytic activity of NTRK2 is ¡°ATP + a [protein]-L-tyrosine = ADP + a [protein]-L-tyrosine phosphate¡±. NTRK2 / TrkB involved in the development and the maturation of the central and the peripheral nervous systems through regulation of neuron survival, proliferation, migration, differentiation, and synapse formation and plasticity.