SLC6A4 and Parkinson disease: Studies performed on rodents and primates have found that modulation of serotonergic activity using 5-HT receptor type 1A and 1B (5-HT1A and 5-HT1B ) agonists such as buspirone and eltoprazine, acute 5-HT transporter (SERT) blockade, or elimination of serotonin (5-HT) afferent terminals may reduce the severity of LIDs without exacerbating PD manifestations (Bezard et al., 2013[5]; Conti et al., 2014[18]; Eskow et al., 2007[26]; Munoz et al., 2008[59]).