Spider venoms inhibit L-glutamate binding to brain synaptic membrane 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 membranes. 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.
D000818:Animals; D001180:Arthropod Venoms / Q000494:pharmacology*; D001921:Brain / Q000378:metabolism*; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D017470:Receptors, Glutamate; D013045:Species Specificity; D013111:Spider Venoms / Q000494:pharmacology*; D013570:Synaptic Membranes / Q000187:drug effects / Q000378:metabolism*
D001180:Arthropod Venoms; D005971:Glutamates; D011956:Receptors, Cell Surface; D017470:Receptors, Glutamate; D013111:Spider Venoms; D018698:Glutamic Acid