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

• Published in: British journal of pharmacology Vol. 139; no. 7; pp. 1297 - 1309
• Main Authors: Fontana, Andréia Cristina Karklin, Guizzo, Renato, Beleboni, Renê de Oliveira, Meirelles e Silva, Antonio Renato, Coimbra, Norberto Cysne, Amara, Susan G, Santos, Wagner Ferreira dos, Coutinho‐Netto, Joaquim
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-08-2003; Nature Publishing
• Subjects: acute glaucoma; Animals; Biological and medical sciences; Brazil; Carbon Isotopes; Cerebral Cortex - cytology; Chromatography, High Pressure Liquid - methods; Chromatography, Ion Exchange; Disease Models, Animal; Dose-Response Relationship, Drug; GABA uptake; gamma-Aminobutyric Acid - drug effects; gamma-Aminobutyric Acid - pharmacokinetics; gamma-Aminobutyric Acid - secretion; Glaucoma - drug therapy; Glaucoma - physiopathology; Glutamate uptake; Glutamic Acid - drug effects; Glutamic Acid - pharmacokinetics; Glutamic Acid - secretion; Ion Channels - drug effects; Ion Channels - metabolism; Ion Channels - physiopathology; Male; Medical sciences; neuroprotection; Neuroprotective Agents - chemistry; Neuroprotective Agents - isolation & purification; Neuroprotective Agents - pharmacology; neurotransmitter transport; Pharmacology. Drug treatments; purification; Rats; Rats, Wistar; Receptors, Metabotropic Glutamate - drug effects; Receptors, Metabotropic Glutamate - physiology; Retina - drug effects; Retina - pathology; Retina - ultrastructure; spider venom; Spider Venoms - chemistry; Spider Venoms - isolation & purification; Spider Venoms - pharmacology; Spiders; synaptosomes; Synaptosomes - drug effects; Synaptosomes - secretion; Tissue Extracts - pharmacology; Tritium; Brazil; Glaucoma; Neuroprotection; neurotransmitter transport; Biological transport; Synaptosome; Glaucoma (eye); Neuromediator; acute glaucoma; spider venom; Protozoa; Purification; synaptosomes; Glutamate; Glutamate uptake; Uptake; Eye disease; Arachnida; Arthropoda; Venom; Excitatory aminoacid; GABA; Neurotransmitter; Ciliata; GABA uptake; Invertebrata
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1038/sj.bjp.0705352

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