neuron-to-neuron signaling pathway via the chemical synapse excitatory synaptic transmission pathway PW:0000455 Synaptic transmission, or neurotransmission is the pathway of neuron-to-neuron signaling via the chemical synapse and mediated by neurotransmitters. Their effect can be excitatory or inhibitory and many neurotransmitters can exert either effect. The major excitatory neurotransmitter is the amino acid glutamate. excitatory neurotransmission pathway pathway