Notably, the beneficial effects of PDE inhibition and GUCY2C activation in the treatment of Parkinson’s disease extend beyond boosting the dopamine biosynthesis machinery, as it could provide a favorable disease-modifying role through multiple interrelated cyclic nucleotide-mediated signaling pathways that contribute to Parkinson’s disease pathophysiology [54, 61, 148]. Here, GUCY2C is linked to Parkinson disease.