Effects of Black Widow Spider Venom, Substance P and Bradykinin on the Release of Endogenous Glutamate From the Frog Spinal Cord

The release of glutamate and aspartate from the hemisected frog spinal cord was measured using black widow spider venom (BWSV), substance P (SP) and bradykinin (BK). The concentration of glutamate and aspartate in the perfusate was measured by fragmentography. The release of glutamate and aspartate was increased by treatment with BWSV. Application of 100 μM SP and BK increased the release of glutamate with little change in the aspartate release. The release of glutamate produced by BWSV and peptides was observed in the presence of tetrodotoxin (10-7 g/ml). It is suggested that BWSV and peptides act on the presynaptic terminals and cause the release of transmitter.