Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family. It shares high structural homology to nerve growth factor (NGF), neurotrophin 3 (NT-3) and neurotrophin 4 (NT-4), but they all operate via different high-affinity membrane receptors and differ in target specificity. BDNF has been shown to support the survival of existing neurons, the growth and differentiation of new neurons and synapses, as well as their function in the peripheral and the central nervous system. High expression levels of BDNF have been detected in the hippocampus, cerebellum, and cortex. Furthermore BDNF is expressed in the pituitary gland, spinal cord, heart, lung, and skeletal muscle. BDNF has been shown to bind with high affinity and specifically activate the cell surface TrkB tyrosine receptor kinase. The amino acid sequence of human and mouse BDNF is identical.
