Brain-derivedneurotrophicfactor(BDNF)isamemberoftheneurotrophinfamily.Itshareshighstructuralhomologytonervegrowthfactor(NGF),neurotrophin3(NT-3)andneurotrophin4(NT-4),buttheyalloperateviadifferenthigh-affinitymembranereceptorsanddifferintargetspecificity.BDNFhasbeenshowntosupportthesurvivalofexistingneurons,thegrowthanddifferentiationofnewneuronsandsynapses,aswellastheirfunctionintheperipheralandthecentralnervoussystem.HighexpressionlevelsofBDNFhavebeendetectedinthehippocampus,cerebellum,andcortex.Fur
ThermoreBDNFisexpressedinthepituitarygland,spinalcord,heart,lung,andskeletalmuscle.BDNFhasbeenshowntobindwithhighaffinityandspecificallyactivatethecellsurfaceTrkBtyrosinereceptorkinase.TheaminoacidsequenceofhumanandmouseBDNFisidentical.