Taurine Fails to Protect Against 1-methyl-4-phenyl-1,2,3,6- Tetrahydropyridine-Induced Striatal Dopamine Depletion in Mice

The potent parkinsonian neurotoxin, 1-methyl-4-phenyl- 1,2,3,6-tetrahydropyridine (MPTP) through its oxidized metabolite, 1-methyl-4-phenylpyridinium (MPPþ) causes lesion specifically to the dopaminergic system of the substantia nigra pars compacta (SNpc) of the brain (Burns et al., 1983). This ability of MPTP and MPPþ has been exploited to develop animal models for Parkinson’s disease (PD). MPTP crosses the blood–brain barrier, gets converted to its neurotoxically active metabolite MPPþ by monoamine oxidase-B in astrocytes and is selectively taken up into dopaminergic neurons by dopamine (DA) transporters (Javitch et al., 1985; Ransom et al., 1987), where it is sequestered into the mitochondria (Ramsay and Singer, 1986). MPPþ causes mitochondrial complex I inhibition, leading to an out surge of free radical species as the lethal process in the neuronal death (Tieu et al., 2003)