TAC1 and Alzheimer disease: However, the benefit of inhibiting substance P/NK-1R interactions in other neurological disorders, including Alzheimer’s disease and Parkinson’s disease, is more equivocal due to the reported neuroprotective properties of this neuropeptide and/or its ability to stimulate non-amyloidogenic amyloid precursor protein processing (as discussed in Chen et al., 2004; Severini et al., 2016).