BDNF and Parkinson disease: Another of NTs is brain-derived neurotrophic factor (BDNF), which, due to its potential neuroprotective effects, is the subject of much research in developing therapies for diseases such as Parkinson’s disease, amyotrophic lateral sclerosis, Alzheimer’s disease, and glaucoma (Arancibia et al., 2008; Greenberg et al., 2009; Allen et al., 2013; Domenici et al., 2014; Kimura et al., 2016).