GIPR and Parkinson disease: Preclinical models of PD indicate that activation of the gastric inhibitory polypeptide receptor, either alone or in combination with stimulation of the glucagon-like peptide 1 receptor (GLP-1), reduces α-synuclein aggregation, protects dopaminergic neurons, and suppresses neuroinflammatory responses, potentially through cyclic adenosine monophosphate protein kinase A (cAMP) response element-binding protein and phosphatidylinositol 3 kinase protein kinase B signalling (PI3K-Akt) pathways [76,77].