Glossary of "Life (9th ed.)" by Sadava et al. (2011)
- A substance produced in and released by a neuron (the presynaptic cell ) that diffuses across a synapse and excites or inhibits another cell (the postsynaptic cell).
- Sadava, D., Hillis, D. M., Heller, H. C. & Berenbaum, M. R. 2011. Life: The Science of Biology, 9th ed. -xliv + 1266 pp. Sinauer Associates, Inc., Sunderland.