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Purification of a neuroprotective component of Parawixia bistriata spider venom that enhances glutamate uptake

Purification of a neuroprotective component of Parawixia bistriata spider venom that enhances... In this study, we examined the effects of crude venom from the spider Parawixia bistriata on glutamate and GABA uptake into synaptosomes prepared from rat cerebral cortex. Addition of venom to cortical synaptosomes stimulated glutamate uptake and inhibited GABA uptake in a concentration‐dependent manner. The venom was fractionated using reverse‐phase high‐performance liquid chromatography on a preparative column. The fraction that retained glutamate uptake‐stimulating activity was further purified on a reverse‐phase analytical column followed by ion‐exchange chromatography. The active fraction, referred to as PbTx1.2.3, stimulated glutamate uptake in synaptosomes without changing the KM value, and did not affect GABA uptake. Additional experiments showed that the enhancement of glutamate uptake by PbTx1.2.3 occurs when ionotropic glutamate receptors or voltage‐gated sodium and calcium channels are completely inhibited or when GABA receptors and potassium channels are activated, indicating that the compound may have a direct action on the transporters. In an experimental model for glaucoma in which rat retinas are subjected to ischemia followed by reperfusion, PbTx1.2.3 protected neurons from excitotoxic death in both outer and inner nuclear layers, and ganglion cell layers. This active spider venom component may serve as a basis for designing therapeutic drugs that increase glutamate clearance and limit neurodegeneration. British Journal of Pharmacology (2003) 139, 1297–1309. doi:10.1038/sj.bjp.0705352 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png British Journal of Pharmacology Wiley

Purification of a neuroprotective component of Parawixia bistriata spider venom that enhances glutamate uptake

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References (63)

Publisher
Wiley
Copyright
2003 British Pharmacological Society
ISSN
0007-1188
eISSN
1476-5381
DOI
10.1038/sj.bjp.0705352
pmid
12890709
Publisher site
See Article on Publisher Site

Abstract

In this study, we examined the effects of crude venom from the spider Parawixia bistriata on glutamate and GABA uptake into synaptosomes prepared from rat cerebral cortex. Addition of venom to cortical synaptosomes stimulated glutamate uptake and inhibited GABA uptake in a concentration‐dependent manner. The venom was fractionated using reverse‐phase high‐performance liquid chromatography on a preparative column. The fraction that retained glutamate uptake‐stimulating activity was further purified on a reverse‐phase analytical column followed by ion‐exchange chromatography. The active fraction, referred to as PbTx1.2.3, stimulated glutamate uptake in synaptosomes without changing the KM value, and did not affect GABA uptake. Additional experiments showed that the enhancement of glutamate uptake by PbTx1.2.3 occurs when ionotropic glutamate receptors or voltage‐gated sodium and calcium channels are completely inhibited or when GABA receptors and potassium channels are activated, indicating that the compound may have a direct action on the transporters. In an experimental model for glaucoma in which rat retinas are subjected to ischemia followed by reperfusion, PbTx1.2.3 protected neurons from excitotoxic death in both outer and inner nuclear layers, and ganglion cell layers. This active spider venom component may serve as a basis for designing therapeutic drugs that increase glutamate clearance and limit neurodegeneration. British Journal of Pharmacology (2003) 139, 1297–1309. doi:10.1038/sj.bjp.0705352

Journal

British Journal of Pharmacology – Wiley

Published: Aug 1, 2003

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