MODULATION OF FUNCTIONAL ACTIVITIES OF THE NEUROTOXIN FROM BLACK-WIDOW SPIDER VENOM

We have studied the action of an alpha-latrotoxin (alpha-LTX) complex of two polypeptides (LTX 130 kDa and low molecular weight protein (LMW P) 8 kDa) and the action of a venom fraction containing LTX with exces s LMWP on calcium influx into synaptosomes and PC12 cells as well as o n [C-14[GABA release from synaptosomes. Both preparations considerably activate calcium influx and stimulate [C-14]GABA release from synapto somes. Preincubation of both preparations with antibodies against a 14 amino acid residue C-terminal peptide of LMWP differentially modulate s these effects. Antibodies inhibit induced calcium influx and enhance induced GABA release.