part of occurs in has target start location has target end location has primary input substance with neurotransmitter role neurotransmitter transport chemical synaptic transmission neurotransmitter secretion Reactome:R-HSA-112310 GO:0007269 neurotransmitter secretory pathway A neurotransmitter is any of a group of substances that are released on excitation from the axon terminal of a presynaptic neuron of the central or peripheral nervous system and travel across the synaptic cleft to either excite or inhibit the target cell. Among the many substances that have the properties of a neurotransmitter are acetylcholine, noradrenaline, adrenaline, dopamine, glycine, gamma-aminobutyrate, glutamic acid, substance P, enkephalins, endorphins and serotonin. biological_process neurotransmitter release The regulated release of neurotransmitter from the presynapse into the synaptic cleft via calcium-regulated exocytosis during synaptic transmission. signal release synaptic cleft establishment of localization in cell presynapse signal release from synapse