Glutamate Uptake Is Stimulated by Extracellular S100B in Hippocampal Astrocytes
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S100B is a calcium-binding protein expressed and secreted by astrocytes, which has been implicated in glial-neuronal communication. Extracellular S100B appears to protect hippocampal neurons against toxic concentrations of glutamate. Here we investigated a possible autocrine role of S100B in glutamate uptake activity.
Astrocyte cultures were prepared of hippocampi from neonate Wistar rats. [3H] Glutamate uptake was measured after addition of S100B protein, antibody anti-S100B or TRTK-12, a peptide that blocks S100B activity mediated by the C-terminal region.
Antibody anti-S100B addition decreased glutamate uptake measured 30 min after medium replacement, without affecting cell integrity or viability. Moreover, low levels of S100B (less than 0.1 ng/mL) stimulated glutamate uptake measured immediately after medium replacement.
This finding reinforces the importance of astrocytes in the glutamatergic transmission, particularly the role of S100B neuroprotection against excitotoxic damage.
Keywordsastrocyte excitotoxicity glutamate uptake S100B
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- Ahlemeyer, B., Beier, H., Semkova, I., Schaper, C., and Krieglstein, J. (2000). S-100beta protects cultured neurons against glutamate- and staurosporine-induced damage and is involved in the antiapoptotic action of the 5 HT(1A)-receptor agonist, Bay x 3702. Brain Res. 858:121–128.CrossRefPubMedGoogle Scholar
- Chen, Y., and Swanson, R. A. (2003). Astrocytes and brain injury. J. Cer. Blood F. Metab. 23:137–149.Google Scholar
- Gonçalves, D. S., Lenz, G., Karl, J., Gonçalves, C. A., and Rodnight, R. (2000). Extracellular S100B protein modulates ERK in astrocyte cultures. NeuroReport 11:807–809.Google Scholar
- Gottfried, C., Tramontina, F., Gonçalves, D., Gonçalves, C. A., Moriguchi, E., Dias, R. D., Wofchuk, S. T., and Souza, D. O. (2002). Glutamate uptake in cultured astrocytes depends on age: A study about the effect of guanosine and the sensitivity to oxidative stress induced by H(2)O(2). Mech. Ageing Dev. 123:1333–1340.CrossRefPubMedGoogle Scholar
- Kogel, D., Peters, M., Konig, H. G., Hashemi, S. M., Bui, N. T., Arolt, V., Rothermundt, M., and Prehn, J. H. (2004). S100B potently activates p65/c-Rel transcriptional complexes in hippocampal neurons: Clinical implications for the role of S100B in excitotoxic brain injury. Neuroscience 127:913–920.CrossRefPubMedGoogle Scholar