Spider toxin (JSTX) blocks glutamate synapse in hippocampal pyramidal neurons

Effects of a spider toxin (JSTX) — a specific blocker of glutamate receptors — on single pyramidal neurons of the hippocampus were studied using tissue slices in vitro. JSTX blocked the synaptic response in CA 1 pyramidal cells evoked by Schaffer collateral stimulation without affecting the antidromic spike potential. The toxin suppressed glutamate-induced cell firings whereas it had little effect on aspartate-induced responses. The results suggest that glutamate is a neurotransmitter of the Schaffer collateral input to CA 1 pyramidal neurons.