MTOR and Parkinson disease: A total of 1150 significantly differential metabolites were identified between the HN and LN groups, such as cotinine, NNAL-N-glucuronide, and 11-dehydrothromboxane-B2, which were significantly enriched in some metabolism-related pathways, such as caffeine metabolism, arachidonic acid metabolism, arginine biosynthesis, and arginine and proline metabolism, as well as several disease-related signaling pathways, such as cGMP-PKG signaling pathway, AMPK signaling pathway, mTOR signaling pathway, and Parkinson’s disease.