Another PD animal model with 6-OHDA-induced right medial forebrain bundle (MFB) lesions has been found to exhibit significantly increased VIP and reduced nNOS expression without altered ChAT expression in the distal ileum and proximal colon (Colucci et al., 2012), whereas EFS evoked-ACh release are significantly reduced in colon (Fornai et al., 2016). This evidence concerns the gene NOS1 and Parkinson disease.