Effects of dopamine and serotonin antagonist injections into the striatopallidal complex of asymptomatic MPTP-treated monkeys

► DA and 5-HT antagonists into the BG on MPTP-treated monkey induce PD symptoms. ► DA in the striatum and GPe is involved in compensatory mechanisms of motor symptoms. ► 5-HT in the same structures appears involved in the expression of non-motor symptoms.