Parkinson’s disease (PD) is a neurological degenerative disorder characterized by loss of dopaminergic neurons in the substantia nigra (SN) and intracellular inclusions called Lewy bodies and Lewy tangles, composed mainly by aggregates of α-synuclein. Braak et al. (2003) proposed that the olfactory epithelium and intestines are the anatomical sites where PD initiates; as pathological aggregates of α-synuclein are detected in these tissues in very early or prodromal PD. In this scenario, α-synuclein seems to reach the central nervous system (CNS) by axonal transport through the sympathetic nervous system, the glossopharyngeal and vagus nerves as well as the olfactory pathways (Braak et al., 2003).