Spider Venoms Inhibit L-glutamate Binding to Brain Synaptic Membrance Receptors

The venoms from three spider species, Araneus gemma, Neoscona arabesca, and Argiope aurantia, were shown to inhibit the high-affinity, sodium-independent L-glutamate-binding sites in rat brain synaptic membrances. The same three venoms caused concentration-dependent inhibition of the activity of the...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1984-09, Vol.81 (17), p.5571-5574
Main Authors: Michaelis, E. K., Galton, N., Early, S. L.
Format: Article
Language:English
Subjects:
Binding sites
Brain
Ligands
Rats
Receptors
Spider venoms
Spiders
Synapses
Toxins
Venoms
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Summary:The venoms from three spider species, Araneus gemma, Neoscona arabesca, and Argiope aurantia, were shown to inhibit the high-affinity, sodium-independent L-glutamate-binding sites in rat brain synaptic membrances. The same three venoms caused concentration-dependent inhibition of the activity of the glutamate-binding glycoprotein purified from rat brain synaptic membranes. The venom milked from the glands of Araneus gemma was the most active inhibitor of L-glutamate binding, causing 60-80% inhibition of both synaptic membrane and purified protein binding activity at 0.01 unit. The inhibitory activity of this venom was associated with a single protein peak obtained from gel permeation chromatography of the venom. Finally, the effect of the venom from Araneus gemma on the synaptic membrane glutamate-binding sites was slowly reversible. These observations indicate that the spider venoms have a direct effect on the recognition sites for L-glutamic acid in brain synaptic membranes and that these sites are related to the physiologic glutamate receptors.
ISSN:0027-8424