[Postsynaptic membrane sensitivity to acetylcholine during blockade of excitatory transmission from nerve to skeletal muscle during long-term low-frequency transmission].

Blocking of myoneural transmission resulting from indirect low-frequency stimulation (fatigue) was not followed by amplitude changes in miniature end-plate potentials and acetylcholine-potentials. A conclusion was drawn that in performed experiments the acetylcholine sensitivity of the postsynaptic membrane was not changed and the decrease of endplate potentials amplitude during fatigue was due to the lowering of EPPs quantum content. A reduction in the quantum content of EPP results from negative antidromic influence of the muscle on the motor nerve endings caused by chemical agents formed in muscle during its contractile appartus activity.