[Effect of alpha-latrotoxin on synaptic transmission between identified neurons in Helix central nervous system].

An identified monosynaptic peptidergic contact between identified neurons from the brain of snail Helix pomatia L. has been used to study the effect of alpha-latrotoxin. It was found that being applied extracellularly the toxin evoked an increase of the postsynaptic response amplitude. Intracellular injection of the toxin into the soma of the presynaptic neuron led to a decrease of the postsynaptic current amplitude. Current induced by intracellular injection of cAMP into postsynaptic neuron was also inhibited either by extra- or intracellular application of the toxin. According to previous data which demonstrate similarity between the postsynaptic response and the current which was induced by intracellular injection of cAMP into postsynaptic neuron it has been proposed that the toxin evokes both an increase of the transmitter release from the presynaptic neuron and a decrease of the postsynaptic response amplitude.