A mediator is a biologically active substance that is released from the endings of an axon under the action of nerve impulses; it mediates between cells in a typical chemical synapse (synapse is the place of contact of a neuron with another cell). The mediator comes into contact with receptors sensitive to it, located on the membrane of a neighboring cell. Depending on the chemical nature of the mediator, it either forms nerve impulses, or for some time goes into a state of inhibition.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.