[Model of electrical feedback mechanisms through chemical synapses].

The model of excitatory chemical synapse is proposed in which the feed-back between the post- and presynaptic neurones is carried out by means of synaptic current generated by postsynaptic neurone. In the model, the potential drop generated by this current along the intercellular gap near the activated synapse (RIII) evokes additional depolarization of presynaptic membrane and thus stimulates the additional release of transmitter (fig. 1, A and B). The feed-back, which increases the steepness of transfer function between pre- and postsynaptic neurones is the more effective the higher the resistance of intercellular gap (fig. 2 and 3, B). is very low, so that activation of synapse is unable to change significantly its membrane potential (V2), the feed-back is the most effective, as revealed in additional depolarization of presynaptic membrane (VII in fig. 3, A). In inhibitory synapse the feed-back by electrical current is negative one.