The depression of nerve stimulation evoked number of quanta (EPC) by glutamate was removed by inhibition of the NO production in the muscle and the NO cascade is common post-receptor pathway started by both glutamate and adenosine presynaptic receptors. Spontaneously released quanta (MEPCs) are not regulated by NO cascade in the presence of glutamate and its specific effect on the evoked release points to modulation (phosphorylation) of the voltage-dependent Ca2+ channels at the release zone that are necessary for evoked quantal release during nerve stimulation.