title: Active uptake of MPP+, a metabolite of MPTP, by brain synaptosomes.
abstract: Mouse brain synaptosomal preparations were used to study uptake of N-methyl-4-phenylpyridine (MPP+), a metabolite of the neurotoxin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine). The uptake of [3H]-MPP+ by striatal synaptosomes was approximately 25 X greater than that of [3H]-MPTP, with a KM of 0.48 microM and a Vmax of 5.3 nmoles/g tissue/min. Uptake was Na+ dependent and inhibited by ouabain, cocaine and dopamine (Ki 0.12 microM). Synaptosomes prepared from the corpus striatum accumulated [3H]-MPP+ at a rate 5-10 times higher than preparations from other brain regions. This selective uptake of MPP+ may contribute to the specificity of the toxic effects of MPTP on nigrostriatal dopaminergic neurons.
mesh_terms: D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D015655:1-Methyl-4-phenylpyridinium; D000818:Animals; D001693:Biological Transport, Active; D001921:Brain / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism; D011725:Pyridines / Q000378:metabolism*; D011726:Pyridinium Compounds / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*
chemical_list: D011725:Pyridines; D011726:Pyridinium Compounds; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D015655:1-Methyl-4-phenylpyridinium; D004298:Dopamine