A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell.[1]
Neurotransmitters are released from synaptic vesicles into the synaptic cleft where they are able to interact with neurotransmitter receptors on the target cell. The neurotransmitter's effect on the target cell is determined by the receptor it binds to. Many neurotransmitters are synthesized from simple and plentiful precursors such as amino acids, which are readily available and often require a small number of biosynthetic steps for conversion.
Neurotransmitters are essential to the function of complex neural systems. The exact number of unique neurotransmitters in humans is unknown, but more than 100 have been identified.[2] Common neurotransmitters include glutamate, GABA, acetylcholine, glycine and norepinephrine.
- ^ Smelser, Neil J.; Baltes, Paul B. (2001). International encyclopedia of the social & behavioral sciences (1st ed.). Amsterdam New York: Elsevier. ISBN 978-0-08-043076-8.
- ^ Cuevas J (1 January 2019). "Neurotransmitters and Their Life Cycle". Reference Module in Biomedical Sciences. Elsevier. doi:10.1016/b978-0-12-801238-3.11318-2. ISBN 978-0-12-801238-3.