MPTP hydrochloride is a brain penetrant dopamine neurotoxin, inducing Parkinson’s Disease. MPTP hydrochloride, a precusor of MPP⁺, induces apoptosis^[1][2][3]. In Vitro: Pretreatment with 50 mM 4-phenylpyridine, reduces IC₅₀ (concentration for 50% inhibition of twitch amplitude) values of MPTP from 53 to 18 mM and d-tubocurarine from 0.7 to 0.3 mM, respectively, in mouse phrenic nerve-diaphragm^[2]. In Vivo: The toxic effect of MPTP can be completely abolished in vivo by treatment with a monoamine oxidase inhibitor and potentiated by an inhibitor of catechol-O-methyltransferase^[1]. Gas1 expressions are significantly elevated in the majority of the reactive astrocytes of the brains with LPS or MPTP insults in animal models^[3].