MAPT and Parkinson disease: Given the significant upregulation of A1R signaling and notable tau phosphorylation have also been observed in Parkinson's disease (PD) and Amyotrophic lateral sclerosis (ALS),[42, 43, 44, 45] we propose that this vicious cycle mechanism mediated by tau pathology and A1R signaling may extend beyond HSD and AD models, influencing the pathological mechanisms in various neurodegenerative disorders.