To test this hypothesis, we examined the amelioration of dopaminergic neuron death by the GLP-1RA to mitochondria-dependent apoptosis using immunohistochemistry (IHC) stains of apoptosis markers, cleaved caspase 3 and the TUNEL stain (Kühn et al., 2003) in the substantia nigra, the primary site of PD pathology, in experimental mice (Zhang et al., 2020). This evidence concerns the gene CASP3 and Parkinson disease.