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标题：Uptake of 1-Methyl-4-phenylpyridinium Ion (MPP+) and ATP Content in Synaptosomes
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作者：Masami MATSUNAGA ; Yoshihiro SHIRANE ; Toshihiro AIUCHI 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：1996
卷号：19
期号：1
页码：29-33
DOI：10.1248/bpb.19.29
出版社：The Pharmaceutical Society of Japan
摘要：Symptoms such as those in Parkinson's disease are known to be induced by the neurotoxin, 1-methyl-4-phenylpyridinium (MPP⁺). We tried to quantitatively measure synaptosomal MPP⁺ uptake using an MPP⁺ selective electrode to study the correlation between MPP⁺ uptake and respiratory inhibition. Synaptosomal MPP⁺ uptake was low but could be increased by the addition of glucose as an energy substrate, or increased with an increase in the concentration of MPP⁺. The rate of uptake was 0.2 nmol/mg protein/min at 50μM MPP⁺. Tetraphenylboron (TPB^-), which enhances cation permeability, increased MPP⁺ uptake, and the increase was proportional to the TPB^- concention. When external MPP⁺ concentration was increased above 200μM, ATP was depleted and the uptake of MPP⁺ decreased, which resulted in the release of intrasynaptosomal MPP⁺. MPP⁺ uptake was also decreased by depolarization of the membrane potential in synaptosomes. MPP⁺ was presumed to be distributed across both the synaptosomal and inner mitochondrial membranes, and to be affected by membrane potential as a lipophilic cation. When respiration of the inner mitochondria was inhibited by increasing the intrasynaptosomal MPP⁺ concentration, the concentration of MPP⁺ in cytosol was presumed to increase by the release of MPP⁺ from the mitochondria, and synaptosomal MPP⁺ uptake would then be decreased.
关键词：1-methyl-4-phenylpyridinium ion;tetraphenylboron;synaptosome