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ATP‐sensitive potassium channel opener iptakalim protected against the cytotoxicity of MPP + on SH‐SY5Y cells by decreasing extracellular glutamate level
Author(s) -
Hu LiFang,
Wang Sen,
Shi XueRu,
Yao HongHong,
Sun YeHong,
Ding JianHua,
Liu ShuYi,
Hu Gang
Publication year - 2005
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.1471-4159.2005.03306.x
Subject(s) - glutamate receptor , chemistry , extracellular , potassium channel , pharmacology , atp sensitive potassium channel , excitotoxicity , sh sy5y , glutamate aspartate transporter , channel blocker , microbiology and biotechnology , biochemistry , biophysics , cell culture , biology , metabotropic glutamate receptor , glibenclamide , endocrinology , receptor , organic chemistry , calcium , genetics , neuroblastoma , diabetes mellitus
Mounting evidence reveals that ATP‐sensitive potassium (K ATP ) channel openers (KCOs) exert significant neuroprotection in vivo and in vitro in several models of Parkinson's disease (PD). However, the mechanisms are not well understood. In this study, we demonstrated that SH‐SY5Y cells expressed mRNA and proteins for Kir6.1, Kir6.2, SUR1 and SUR2 subunits of K ATP channels. Moreover, our results showed that 1‐methyl‐4‐phenyl‐pyridinium ion (MPP + ) induced up‐regulation of mRNA for the Kir6.2 subunit and down‐regulation of SUR1. It was further found that pretreatment with iptakalim, a novel K ATP channel opener, could attenuate increased extracellular glutamate level and decreased cell survival in SH‐SY5Y cell culture after exposure to MPP + . Trans‐pyrrolidine‐2, 4‐dicarboxylic acid ( t ‐PDC), a glutamate transporter inhibitor, partially blocked the effect of iptakalim decreasing extracellular glutamate level. Additionally, iptakalim prevented MPP + ‐induced inhibition of glutamate uptake in primary cultured astrocytes. The beneficial effects of iptakalim on glutamate uptake of astrocytes were abolished by selective mitochondrial K ATP (mitoK ATP ) channel blocker 5‐HD. These results suggest (i) K ATP channel dysfunction may be involved in the mechanisms of MPP + ‐induced cytotoxicity and (ii) iptakalim may modulate glutamate transporters and subsequently alleviate the increase of extracellular glutamate levels induced by MPP + through opening mitoK ATP channels, thereby protecting SH‐SY5Y cells against MPP + ‐induced cytotoxicity.