Brain Derived Neurotrophic Factor, or BDNF, is a nerve growth factor that supports neuron growth and survival. BDNF shares identical domains with two other neurotrophic factors known as, beta -NGF and NT-3 (neurotrophin-3). BDNF binds with low affinity to a receptor known as LNGFR, which also binds NGF and NT-3, but mediates survival function by signaling through a high affinity receptor known as gp145/TrkB. , , and pig BDNF are all cross-reactive. Recombinant BDNF is a non-glycosylated homodimer, containing two 119 amino acid chains, with a total molecular weight of 27 kDa.