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Effect of N ‐Methyl‐4‐Phenylpyridinium Ion on Monoamine Oxidase in a Clonal Rat Pheochromocytoma Cell Line, PC 12h
Author(s) -
Naoi Makoto,
Suzuki Hiroko,
Kiuchi Kazutoshi,
Takahashi Tsutomu,
Nagatsu Toshiharu
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb05755.x
Subject(s) - monoamine oxidase , neurotoxin , tyrosine hydroxylase , dopaminergic , medicine , chemistry , dopamine , incubation , endocrinology , cell culture , mptp , enzyme , biochemistry , biology , genetics
The effects of the neurotoxin N ‐methyl‐4‐phenylpyridinium ion (MPP + ) on the enzymes involved in synthesis and catabolism of catecholamines were examined using a clonal rat pheochromocytoma cell line, PC12h, as a model of dopaminergic neurons. MPP + added in the culture medium was found to be accumulated in PC12h cells after 30‐min incubation. Monoamine oxidase (MAO) activity in PC12h cells was inhibited by MPP + in a dose‐dependent way from 10 n M to 10 μ M , but concentrations of MPP + higher than 100 μ M were found to increase the MAO activity. At the lower concentrations MPP + inhibited MAO non‐competitively with respect to the substrate, kynuramine, and at the higher concentrations it increased both the K m and the V max values of MAO toward the substrate. On the other hand, tyrosine hydroxylase activity and the dopamine concentrations in PC 12 cells were not changed by incubation with MPP + for 30 min, 60 min, or 24 h.