As a neuroprotective agent in PD models against DA neuron toxins such as 6-hyroxydopamine (6-OHDA) or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), BDNF is effective at protecting SH-SY5Y neuroblastoma neurons in vitro and can modestly protect against 6-OHDA in vivo [183]. Here, BDNF is linked to Parkinson disease.