Ion-channel block in insect muscle fibre membrane by the venom of the digger wasp, Philanthus triangulum F.

External miniature postsynaptic potentials were recorded from fibres of the metathoracic retractor unguis muscle of Schistocerca gregaria. At concentrations from 0.4 to 0.5 bee units/ml the venom of European Philanthus triangulum causes a decrease in amplitude and in half-decay time of miniature potentials. It is suggested that the venom, partially blocks the current by shortening the ion-channel open-life-time in the postsynaptic membrane.