Effects of α-latrotoxin on synaptic transmission between identified neurons in the snail central nervous system

The effects of α-latrotoxin — a component of black widow spider venom — on an identified monosynaptic peptidergic synapse were investigated in the central nervous system ofHelix pomatia. Extracellular and intracellular application of the toxin was found to increase and block postsynaptic current respectively. Current induced by intracellular injection of cAMP which imitates postsynaptic current was inhibited, irrespective of the mode of toxin application. It was concluded on the basis of the experiments performed that α-latrotoxin manifests its reinforcing effect, acting on the transmitter release system in the presynaptic neuron. It can also induce an inhibitory effect, however, operating on the postsynaptic cell direct — an effect which may be mediated by the cAMP system.