Brain Derived Neurotrophic Factor (BDNF) is a member of the neurotrophin family, which includes NGF, NT-3, and NT-4/5. This family is likely derived from a common ancestral gene and share similar sequences and structures. BDNF has a molecular weight of ~27 kDa and exists as a homodimer. It shares a common cysteine knot structure with the other members of the neurotrophin family. BDNF has a precursor peptide known as proBDNF, and during processing the cleaved pro-domain is packaged and co-secreted with the mature BDNF form. The effects of proBDNF are less defined than those of the mature BDNF form. BDNF’s effects are mostly mediated through the TrkB receptor, though it can also bind to a pan-neurotrophin receptor known as p75. BDNF is associated with almost all aspects of the nervous system, promoting neuronal survival and differentiation, modulating synaptic plasticity, synapse formation, neuronal excitability, LTP, etc. It has important roles within the development of the nervous system into adulthood. Several studies have demonstrated possible links to various disease states and conditions including: Alzheimer’s disease, OCD, depression, Huntington’s disease, schizophrenia and dementia.