Suppression of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic neurotoxicity in mouse brain by piroheptine and trihexyphenidyl

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produces a parkinsonian state in monkeys and humans and a marked 3,4-dihydroxyphenylethylamine (dopamine) depletion in mouse striatum. In this study, we found that pretreatment with 3-(10,11,-dihydro-5H-dibenzo-[a,d]-cycloheptan-5-ylidene)-1-ethyl- 2- methylpyrrolidine (piroheptine), an anticholinergic drug which also inhibits dopamine uptake completely prevented loss of striatal dopamine in MPTP-treated mice. Trihexyphenidyl partially protected against the neurotoxicity of MPTP. However, clomipramine, a selective 5-hydroxytryptamine uptake inhibitor, did not prevent the loss of striatal dopamine. Piroheptine is another agent which was found to prevent MPTP neurotoxicity.