[Interaction of black widow spider toxin with bilayer phospholipid membranes].

Black widow spider toxin (latrotoxin) was studied for its effect on bilayer phospholipid membrane conductance. Under the toxin action membranes became selective with respect to divalent cations. The selectivity decreased in the following order: Ba2+, Sr2+, Ca2+, Mg2+. The ion channels formed by toxin in a planar membrane were effectively blocked by Cd2+. Current-voltage characteristics of the membranes permit concluding that toxin molecules are incorporated into a plane bilayer in the oriented way and the formed channels are potential-dependent.