Spider toxin blocks excitatory amino acid responses in isolated hippocampal pyramidal neurons.
Using the 'concentration-clamp' technique we have investigated the action of Joro spider toxin (JSTX), as a specific blocker of glutamate receptor, on freshly isolated rat hippocampal pyramidal neurons. The neurons showed prominent responses to L-glutamate (L-Glu), quisqualate (QA) and kainate (KA) and JSTX blocked completely the both responses. The blocking action of toxin was dose-dependent at the concentrations of toxin between 4.8 X 10(-12) and 4.8 X 10(-8) M, and was remarkably similar in cell to cell trials. The kinetics of blockade was revealed by applying the toxin to the non-desensitizing KA response. We suggest that the JSTX spider toxin may be a valuable tool in ligand binding studies of QA/KA receptors in the central nervous system.
D000818:Animals; D001180:Arthropod Venoms / Q000494:pharmacology*; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D007608:Kainic Acid / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D009498:Neurotoxins / Q000494:pharmacology*; D010069:Oxadiazoles / Q000494:pharmacology*; D016318:Quisqualic Acid; D051381:Rats; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000187:drug effects; D013111:Spider Venoms / Q000494:pharmacology*; D013997:Time Factors
D001180:Arthropod Venoms; D005971:Glutamates; D009498:Neurotoxins; D010069:Oxadiazoles; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D013111:Spider Venoms; D018698:Glutamic Acid; D016318:Quisqualic Acid; D007608:Kainic Acid