Neurotransmitters and receptors

There are many different neurotransmitters in the CNS, each binding to a specific receptor type which has a distinct distribution and role within the CNS.^[1,2,3] Some common neurotransmitters are listed in the table on this slide. Defects in many neurotransmitter pathways have been implicated in psychiatric disorders.

The variety of neurotransmitters that operate within the CNS adds to the functional complexity of the brain.^[2] Different neurotransmitters can produce different responses on the same neurone; e.g., a neurone might be excited by serotonin but inhibited by the binding of GABA.^[2]

Exactly what constitutes a neurotransmitter has been the subject of some disagreement but, generally, a neurotransmitter must:^[2]

• be present within the presynaptic neurone
• be released in response to presynapticdepolarisation, and the release must be
  calcium-dependent
• have specific receptors on the postsynaptic neurone

References:
[1] Kandel ER, Schwartz JH, Jessell TM (eds). Principles of Neural Science. 4th edition. McGraw-Hill, 2000.

[2] Purves D, Augustine GJ, Fitzpatrick D, et al. (eds). Neuroscience. 4th edition. Sinauer Associates ,2008.

[3] Stahl SM. Stahl’s Essential Psychopharmacology. Neuroscientific Basis and Practical Applications. 4th edition. © Cambridge University Press, 2013.

[4] Wierońska JM, Zorn SH, Doller D, Pilc A. Metabotropic glutamate receptors as targets for new antipsychotic drugs: Historical perspective and critical comparative assessment. Pharmacol Ther 2016; 157: 10–27.

[5] Grieg NH, Reale M, Tata AM. New advances in pharmacological approaches to the cholinergic system: an overview on muscarinic receptor ligands and cholinesterase inhibitors. Recent Pat CNS Drug Discov 2013; 8 (2): 123–141.

[6] Sadek B, Stark H. Cherry-picked ligands at histamine receptor subtypes. Neuropharmacology 2016; 106: 56–73.