Brain-Derived?Neurotrophic?Factor?（BDNF）?is?a?member?of?the?neurotrophin?family.?Along?with?other?structurally?related?neurotrophic?factors?NGF,?NT-3?and?NT-4,?BDNF?binds?with?high?affinity?to?the?TrkB?kinase?receptor.?It?also?binds?with?the?LNGFR?（for?low-affinity?nerve?growth?factor?receptor,?also?known?as?p75）.?BDNF?promotes?the?survival,?growth?and?differentiation?of?neurons.?It?serves?as?a?major?regulator?of?synaptic?transmission?and?plasticity?at?adult?synapses?in?many?regions?of?the?CNS.?BDNF?expression?is?altered?in?neurodegenerative?disorders?such?as?Parkinson's?and?Alzheimer's?disease.