There are many different neurotransmitters in the CNS, each binding to a specific receptor type which has a distinct distribution and functional role within the CNS.16,17 A neurotransmitter can play many different roles in brain function, depending on how it functions and where in the brain it is active.16,17 Some common neurotransmitters are listed in the table on this slide. Defects in many neurotransmitter pathways have been implicated in psychiatric disorders.18
The variety of neurotransmitters that operate within the CNS adds to the functional complexity of the brain.16 Different neurotransmitters can produce different responses on the same neuron; e.g., a neuron might be excited by serotonin but inhibited by the binding of GABA.19,20
Exactly what constitutes a neurotransmitter has been the subject of some disagreement but, generally, a neurotransmitter must:19,20
- be present within the presynaptic neuron
- be released in response to presynaptic depolarization
- have specific receptors on the postsynaptic neuron.
References:
1. Hassel B, Dingledine R. Glutamate and glutamate receptors. In: Brady ST, Siegel CJ, Albers RW, Price DL (eds). Basic Neurochemistry: Principles of Molecular, Cellular and Medical Neurobiology. 8th edition. Academic Press, 2012.
2. Jewett BE, Sharma S. Physiology, GABA. StatPearls [internet]. 2023.
3. Chen RJ, Sharma S. GABA receptor. StatPearls [internet]. 2025.
4. Bhatia, Lenchner JR, Saadabadi A. Biochemistry, dopamine receptors. StatPearls [internet]. 2023.
5. Bromberg-Martin ES, Matsumoto M, Hikosaka O. Dopamine in motivational control: rewarding, aversive, and alerting. Neuron 2010; 68 (5): 815–834.
6. Dresp-Langley B. From reward to anhedonia–dopamine function in the global mental health context. Biomedicines 2023; 11 (9): 2469.
7. Hussain LS, Reddy V, Maani CV. Physiology, noradrenergic synapse. StatPearls [internet]. 2023.
8. Scammell TE, Jackson AC, Franks NP, et al. Histamine: neural circuits and new medications. Sleep 2019; 42 (1): zsy183.
9. Mika K, Szafarz M, Bednarski M, et al. Metabolic effects of novel histamine H3 receptor ligands in the model of excessive eating: the importance of intrinsic activity and pharmacokinetic properties. Biomed Pharmacother 2021; 142: 111952.
10. Qian H, Shu C, Xiao L, Wang G. Histamine and histamine receptors: roles in major depressive disorder. Front Psychiatry 2022; 13: 825591.
11. Olivier B. Serotonin: A never-ending story. Eur J Pharmacol 2015; 753: 2–18.
12. Millan MJ, Marin P, Bockaert J, Mannoury la Cour C. Signaling at G-protein-coupled serotonin receptors: recent advances and future directions. Trends Pharmacol Sci 2008; 29 (9): 454–464.
13. Picciotto MR, Higley MJ, Mineur YS. Acetylcholine as a neuromodulator: Cholinergic signaling shapes nervous system function and behavior. Neuron 2012; 76 (1): 116–129.
14. Decker AL, Duncan K. Acetylcholine and the complex interdependence of memory and attention. Curr Opin Behav Sci 2020; 32: 1–8.
15. Mizzi N, Blundell R. Glycine receptors: Structure, function, and therapeutic implications. Mol Aspects Med 2025; 103: 101360.
16. Communication between neurons. In: OpenStax. Anatomy and Physiology. Available at: https://openstax.org/books/anatomy-and-physiology.
17. Hansen JY, Shafiei G, Markello RD, et al. Mapping neurotransmitters systems to the structural and functional organization of the human neocortex. Nat Neurosci 2022; 25 (11): 1569–1581.
18. Sheffler ZM, Reddy V, Pillarisetty LS. Physiology, neurotransmitters. StatPearls [internet]. 2023.
19. Neurotransmitters. In: Kandel ER, Koester JD, Mack SH, Siegelbaum SA (eds). Principles of Neural Science. 6th edition. McGraw-Hill, 2021.
20. Neurotransmitters. In: Augustine GJ, Groh J, Huettel S, et al. (eds). Neuroscience. 7th edition. Oxford University Press, 2023.