[Reactions of nervous elements to K+ accumulation in the medium and functional potassium feedback at the synapse].

Increase in (K+)n leads to biphasic cahnges of MP and AP in the frog nerve. The first (ascending) phase at minor K+ accumulation is associated with activation of the membrane electrogenic ionic pump, the second (descending) phase at major K+ accumulation--with deploraization of the membrane. The rhythmic postsynaptic activity (50 Epp/sec.) produces the positive shift of ErevEpp. The latter indicates a potassium accumulation in synaptic cleft. The increase of (K+) in the medium leads also to biphasic change of the quantum contant of the synaptic transmission. The data obtained point out to participation of the synaptic potassium functional feedback (FF) in the phenomena of postactivational potentiation and presynaptic pessimum in the neuromuscular synapse. Hypotheses of participation of the potassium FF of neuro-neuronal synapses in the phenomena of conditioning and domineering, are advanced.