SIRT1 and Parkinson disease: In this study, to further confirm whether the protective effect of teaghrelin in the PD cell model was mediated through activation of the AMPK/SIRT1/PGC1-α pathway, SH-SY5Y cells were incubated with the substance P. As shown in Figure 7, AMPK phosphorylation, SIRT1 expression, and PGC1-α expression were significantly decreased after MPP+ treatment.