Abstract
In SH-SY5Y, a human neuroblastoma cell line, Aroclor 1254 (A1254), induced a dose-dependent (10-50 μg/ml) intracellular calcium concentration ([Ca2+]i) increase. Two rather specific sodium-calcium (Na+-Ca2+) exchanger (NCX) inhibitors, bepridil (10 μM) and KB-R7943 [2-[2-[4-(4-nitrobenzyloxy) phenyl]ethyl]isothiourea methanesulfonate] (10 μM), reduced A1254-induced [Ca2+]i increase. A 24-h exposure to 30 μg/ml A1254 caused remarkable SH-SY5Y neuroblastoma cell damage. It is noteworthy that both bepridil and KB-R7943 counteracted A1254-induced neuronal injury. These results indicate that NCX contributes to [Ca2+]i increase and neuronal injury induced by A1254. RT-PCR experiments revealed in SH-SY5Y neuroblastoma cells the expression of NCX1 and NCX3 isoforms. To investigate which isoform was involved in [Ca2+]i increase and neuronal damage induced by A1254, we used specific antisense oligodeoxynucleotides (ODNs) to reduce NCX1 or NCX3 protein expression. The results showed that only NCX1 ODN reduced [Ca2+]i increase and neuronal injury induced by A1254. In conclusion, these results indicate that NCX1 may participate to [Ca2+]i increase and neurotoxicity evoked by A1254 in SH-SY5Y neuroblastoma cells.
Footnotes
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This work was supported by Ministero dell'Istruzione, dell'Università e della Ricerca (PRIN 2003) (to S.A. and G.D.).
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.105.088948.
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ABBREVIATIONS: PCB, polychlorinated biphenyl(s); A1254, Aroclor 1254; NCX, Na+-Ca2+ exchanger; KB-R7943, 2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl] isothiourea methanesulfonate; ANOVA, analysis of variance; RT-PCR, reverse transcription-polymerase chain reaction; [Ca2+]i, intracellular calcium concentration; MTT, 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide; NMDA, N-methyl-d-aspartate; ODN, oligodeoxynucleotide; VSCC, voltage-sensitive Ca2+ channel(s).
- Received May 2, 2005.
- Accepted July 7, 2005.
- The American Society for Pharmacology and Experimental Therapeutics
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