Editing Neurotransmitter (section)

== Types ==
There are many different ways to classify neurotransmitters. They are commonly classified into [[amino acids]], [[monoamine]]s and [[peptides]].<ref>{{Cite book| vauthors = Prasad BV |title=Examining Biological Foundations of Human Behavior|publisher=IGI Global|year=2020|isbn=978-1799-8286-17|location=United States of America|pages=81}}</ref>

Some of the major neurotransmitters are:
* '''[[Amino acid]]s:''' [[glutamate]],<ref name="twsNovK11">{{cite news| vauthors = Sapolsky R |title=Biology and Human Behavior: The Neurological Origins of Individuality, 2nd |publisher=The Teaching Company|year=2005|quote=see pages 13 & 14 of Guide Book}}</ref> [[aspartate]], [[D-serine]], [[gamma-Aminobutyric acid]] (GABA),{{refn|group=nb|GABA is a ''non-proteinogenic'' amino acid}} [[glycine]]
* '''[[Gasotransmitter]]s:''' [[nitric oxide]] (NO), [[carbon monoxide]] (CO), [[hydrogen sulfide]] (H<sub>2</sub>S)
* '''[[Monoamine]]s:'''
** [[Catecholamine|'''Catecholamines''']]: [[dopamine]] (DA), [[norepinephrine]] (noradrenaline, NE), [[Adrenaline|epinephrine]] (adrenaline)
** '''[[Indolamines]]''': [[serotonin]] (5-HT, SER), [[melatonin]]
** [[histamine]]
* '''[[Trace amine]]s''': [[phenethylamine]], [[N-methylphenethylamine|''N''-methylphenethylamine]], [[tyramine]], [[3-iodothyronamine]], [[octopamine]], [[tryptamine]], etc.
* '''[[Peptide]]s:''' [[oxytocin]], [[somatostatin]], [[substance P]], [[cocaine and amphetamine regulated transcript]], [[opioid peptide]]s<ref name="pmid38738">{{cite journal | vauthors = Snyder SH, Innis RB | title = Peptide neurotransmitters | journal = Annual Review of Biochemistry | volume = 48 | pages = 755–82 | year = 1979 | pmid = 38738 | doi = 10.1146/annurev.bi.48.070179.003543 }}</ref>
* '''[[Purinergic signalling|Purines]]:''' [[adenosine triphosphate]] (ATP), [[adenosine]]
* Others: [[acetylcholine]] (ACh), [[anandamide]], etc.

In addition, over 100 neuroactive [[peptide]]s have been found, and new ones are discovered regularly.<ref>{{cite journal | vauthors = Corbière A, Vaudry H, Chan P, Walet-Balieu ML, Lecroq T, Lefebvre A, Pineau C, Vaudry D | display-authors = 6 | title = Strategies for the Identification of Bioactive Neuropeptides in Vertebrates | journal = Frontiers in Neuroscience | volume = 13 | pages = 948 | date = 18 September 2019 | pmid = 31619945 | pmc = 6759750 | doi = 10.3389/fnins.2019.00948 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Fricker LD, Devi LA | title = Orphan neuropeptides and receptors: Novel therapeutic targets | journal = Pharmacology & Therapeutics | volume = 185 | pages = 26–33 | date = May 2018 | pmid = 29174650 | pmc = 5899030 | doi = 10.1016/j.pharmthera.2017.11.006 }}</ref> Many of these are co-released along with a small-molecule transmitter. Nevertheless, in some cases, a peptide is the primary transmitter at a synapse. [[Beta-Endorphin]] is a relatively well-known example of a peptide neurotransmitter because it engages in highly specific interactions with [[opioid receptors]] in the [[central nervous system]].{{cn|date=January 2025}}

Single [[ions]] (such as synaptically released [[zinc]]) are also considered neurotransmitters by some,<ref>{{cite journal | vauthors = Kodirov SA, Takizawa S, Joseph J, Kandel ER, Shumyatsky GP, Bolshakov VY | title = Synaptically released zinc gates long-term potentiation in fear conditioning pathways | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 103 | issue = 41 | pages = 15218–23 | date = October 2006 | pmid = 17005717 | pmc = 1622803 | doi = 10.1073/pnas.0607131103 | bibcode = 2006PNAS..10315218K | doi-access = free }}</ref> as well as some gaseous molecules such as [[nitric oxide]] (NO), [[carbon monoxide]] (CO), and [[hydrogen sulfide]] (H<sub>2</sub>S).<ref>{{cite web|url=http://www.marsdd.com/mars-library/international-symposium-on-nitric-oxide-dr-john-andrews/|title=International Symposium on Nitric Oxide – Dr. John Andrews – MaRS|work=MaRS|url-status=dead|archive-url=https://web.archive.org/web/20141014083429/http://www.marsdd.com/mars-library/international-symposium-on-nitric-oxide-dr-john-andrews/|archive-date=14 October 2014}}</ref> The gases are produced in the neural cytoplasm and are immediately diffused through the cell membrane into the extracellular fluid and into nearby cells to stimulate production of second messengers. Soluble gas neurotransmitters are difficult to study, as they act rapidly and are immediately broken down, existing for only a few seconds.{{cn|date=January 2025}}

The most prevalent transmitter is [[glutamate]], which is excitatory at well over 90% of the synapses in the human brain.<ref name=twsNovK11/> The next most prevalent is gamma-Aminobutyric Acid, or GABA, which is inhibitory at more than 90% of the synapses that do not use glutamate. Although other transmitters are used in fewer synapses, they may be very important functionally: the great majority of psychoactive drugs exert their effects by altering the actions of some neurotransmitter systems, often acting through transmitters other than glutamate or GABA. Addictive drugs such as cocaine and amphetamines exert their effects primarily on the dopamine system. The addictive [[opiate]] drugs exert their effects primarily as functional analogs of [[opioid peptides]], which, in turn, regulate dopamine levels.{{cn|date=January 2025}}

===List of neurotransmitters, peptides, and gaseous signaling molecules===

{{incomplete list|date=January 2017}}
{| class="wikitable unsortable" style="width:100%"
|<!--Start of inner tables-->
{| class="sortable wikitable" style="width:100%"
|+ Neurotransmitters
 |-
! scope="col" style="width: 15%;" | '''Category'''
! scope="col" style="width: 24%;" | '''Name'''
! scope="col" style="width: 6%;" class="unsortable" | <small>'''Abbreviation'''</small>
! scope="col" style="width: 31%;" | '''[[Metabotropic]]'''
! scope="col" style="width: 24%;" | '''[[Ionotropic]]'''
 |-
|{{abbrlink| Small| Small molecule}}: [[Amino acid]]s ([[Arginine|Arg]]) || [[Arginine]] || Arg, R ||[[Alpha-2 adrenergic receptor|α<sub>2</sub>-Adrenergic receptor]]s, [[imidazoline receptor]]s || [[NMDA receptor]]s
 |-
| Small: Amino acids || [[Aspartate]] || Asp, D || – || [[NMDA receptor]]s
 |-
| Small: Amino acids || [[Glutamate]] || Glu, E ||[[Metabotropic glutamate receptor]]s || [[NMDA receptor]]s, [[kainate receptor]]s, [[AMPAR]]s
 |-
| Small: Amino acids || [[Gamma-aminobutyric acid]] || GABA || [[GABAB receptor|GABA<sub>B</sub> receptor]]s || [[GABAA receptor|GABA<sub>A</sub> receptor]]s, [[GABAA-rho receptor|GABA<sub>A</sub>-ρ receptor]]s
 |-
| Small: Amino acids || [[Glycine]] || Gly, G || – || [[NMDA receptor]]s, [[glycine receptor]]s
 |-
| Small: Amino acids || [[D-serine|<small>D</small>-serine]] || Ser, S || – || [[NMDA receptor]]s
 |-
| Small: Acetylcholine || [[Acetylcholine]] || ACh ||[[Muscarinic acetylcholine receptor]]s || [[Nicotinic acetylcholine receptor]]s
 |-
| Small: [[Monoamine neurotransmitter|Monoamine]] ([[Phenylalanine|Phe]]/[[Tyrosine|Tyr]]) || [[Dopamine]] || DA || [[Dopamine receptor]]s, [[trace amine-associated receptor&nbsp;1]]<ref name="DA IUPHAR">{{cite web|title=Dopamine: Biological activity | url=http://www.guidetopharmacology.org/GRAC/LigandDisplayForward?tab=biology&ligandId=940|work=IUPHAR/BPS guide to pharmacology|publisher=International Union of Basic and Clinical Pharmacology|access-date=29 January 2016}}</ref><ref name="Miller+Grandy 2016">{{cite journal | vauthors = Grandy DK, Miller GM, Li JX | title = "TAARgeting Addiction"--The Alamo Bears Witness to Another Revolution: An Overview of the Plenary Symposium of the 2015 Behavior, Biology and Chemistry Conference | journal = Drug and Alcohol Dependence | volume = 159 | pages = 9–16 | date = February 2016 | pmid = 26644139 | pmc = 4724540 | doi = 10.1016/j.drugalcdep.2015.11.014 | quote = TAAR1 is a high-affinity receptor for METH/AMPH and DA }}</ref> || –
 |-
| Small: Monoamine ([[Phenylalanine|Phe]]/[[Tyrosine|Tyr]]) || [[Norepinephrine]] (noradrenaline) || NE, NAd || [[Adrenergic receptor]]s || –
 |-
| Small: Monoamine ([[Phenylalanine|Phe]]/[[Tyrosine|Tyr]]) || [[Epinephrine]] (adrenaline) || Epi, Ad || [[Adrenergic receptor]]s || –
 |-
| Small: Monoamine ([[Tryptophan|Trp]]) || [[Serotonin]] (5-hydroxytryptamine) || 5-HT || [[Serotonin receptor]]s (all except 5-HT<sub>3</sub>) || [[5-HT3|5-HT<sub>3</sub>]]
 |-
| Small: Monoamine ([[Histidine|His]]) || [[Histamine]] || H || [[Histamine receptor]]s || –
 |-
| Small: [[Trace amine]] ([[Phenylalanine|Phe]]) || [[Phenethylamine]] || PEA || [[Trace amine-associated receptor]]s [[TAAR1]], [[TAAR2]] || –
 |-
| Small: Trace amine ([[Phenylalanine|Phe]]) || [[N-methylphenethylamine|''N''-methylphenethylamine]] || NMPEA || [[TAAR1]] || –
 |-
| Small: Trace amine ([[Phenylalanine|Phe]]/[[Tyrosine|Tyr]]) || [[Tyramine]] || TYR || [[TAAR1]], [[TAAR2]] || –
 |-
| Small: Trace amine ([[Phenylalanine|Phe]]/[[Tyrosine|Tyr]]) || [[octopamine]] || Oct || [[TAAR1]] || –
 |-
| Small: Trace amine ([[Phenylalanine|Phe]]/[[Tyrosine|Tyr]]) || [[Synephrine]] || Syn || [[TAAR1]] || –
 |-
| Small: Trace amine ([[Tryptophan|Trp]]) || [[Tryptamine]] ||  || [[TAAR1]], various [[serotonin receptor]]s || –
 |-
| Small: Trace amine ([[Tryptophan|Trp]]) || [[N-methyltryptamine|''N''-methyltryptamine]] || NMT || [[TAAR1]], various [[serotonin receptor]]s || –
 |-
| Lipid || [[Anandamide]] || AEA || [[Cannabinoid receptor]]s || –
 |-
| Lipid || [[2-Arachidonoylglycerol]] || 2-AG || [[Cannabinoid receptor]]s || –
 |-
| Lipid || [[2-Arachidonyl glyceryl ether]] || 2-AGE || [[Cannabinoid receptor]]s || –
 |-
| Lipid || [[N-Arachidonoyl dopamine|''N''-Arachidonoyl dopamine]] || NADA || [[Cannabinoid receptor]]s || [[TRPV1]]
 |-
| Lipid || [[Virodhamine]] ||   || [[Cannabinoid receptor]]s || –
 |-
| Small: [[Purine]] || [[Adenosine]] || Ado || [[Adenosine receptor]]s || –
 |-
| Small: Purine || [[Adenosine triphosphate]] || ATP || [[P2Y receptor]]s || [[P2X receptor]]s
 |-
| Small: Purine || [[Nicotinamide adenine dinucleotide]] || β-NAD || [[P2Y receptor]]s || [[P2X receptor]]s
 |-
|}
{| class="wikitable sortable" style="width:100%"
|+ [[Neuropeptide]]s
 |-
! scope="col" style="width: 15%;" | '''Category'''
! scope="col" style="width: 24%;" | '''Name'''
! scope="col" style="width: 6%;" class="unsortable" | <small>'''Abbreviation'''</small>
! scope="col" style="width: 31%;" | '''[[Metabotropic]]'''
! scope="col" style="width: 24%;" | '''[[Ionotropic]]'''
 |-
| [[Bombesin-like peptides]]|| [[Bombesin]] ||  || BBR1-2-3 || –
 |-
| Bombesin-like peptide|| [[Gastrin releasing peptide]] || GRP || – || –
 |-
| Bombesin-like peptide|| [[Neuromedin B]] || NMB || [[Neuromedin B receptor]] || –
 |-
| Bradykinins || [[Bradykinin]] ||   || [[Bradykinin receptor B1|B1]], [[Bradykinin receptor B2|B2]] || –
 |-
| [[Amylin family|Calcitonin/CGRP family]]|| [[Calcitonin]] ||   || [[Calcitonin receptor]] || –
 |-
| Amylin family|Calcitonin/CGRP family|| [[Calcitonin gene-related peptide]] || CGRP  || [[CALCRL]] || –
 |-
| [[Corticotropin-releasing factor family|Corticotropin-releasing factors]]|| [[Corticotropin-releasing hormone]] || CRH || [[Corticotropin-releasing hormone receptor 1|CRHR1]] || –
 |-
| Corticotropin-releasing factors|| [[Urocortin]] ||  || [[Corticotropin-releasing hormone receptor 1|CRHR1]] || –
 |-
| Galanins || [[Galanin]] ||  || [[GALR1]], [[GALR2]], [[GALR3]] || –
 |-
| Galanins || [[Galanin-like peptide]] ||  || [[GALR1]], [[GALR2]], [[GALR3]] || –
 |-
| Gastrins || [[Gastrin]] ||  || [[Cholecystokinin B receptor]] || –
 |-
| Gastrins || [[Cholecystokinin]] || CCK || [[Cholecystokinin receptor]]s || –
 |-
| [[Granin]]s || [[Chromogranin A]] || ChgA || – || –
 |-
| [[Melanocortin]]s || [[Adrenocorticotropic hormone]] || ACTH || [[ACTH receptor]] || –
 |-
| Melanocortins || [[Proopiomelanocortin]] || POMC || [[Melanocortin 4 receptor]] || –
 |-
| Melanocortins || [[Melanocyte-stimulating hormone]]s || MSH || [[Melanocortin receptor]]s || –
 |-
| [[Neurohypophyseal]]s || [[Vasopressin]]  || AVP || [[Vasopressin receptor]]s || –
 |-
| Neurohypophyseals || [[Oxytocin]] || OT || [[Oxytocin receptor]] || –
 |-
| Neurohypophyseals || [[Neurophysin I]] ||   || – || –
 |-
| Neurohypophyseals || [[Neurophysin II]] ||   || – || –
 |-
| Neurohypophyseals || [[Copeptin]] ||   || – || –
 |-
| Neuromedins || [[Neuromedin U]] || NmU  ||[[Neuromedin U receptor 1|NmUR1]], [[Neuromedin U receptor 2|NmUR2]]|| –
 |-
| Neuropeptide B/W || [[Neuropeptide B]] || NPB || [[NPBWR1|NPBW1]], [[Neuropeptides B/W receptor 2|NPBW2]] || –
 |-
| Neuropeptide B/W || [[Neuropeptide S]] || NPS || [[Neuropeptide S receptor]]s || –
 |-
| Neuropeptide Y || [[Neuropeptide Y]] || NY || [[Neuropeptide Y receptor]]s || –
 |-
| Neuropeptide Y || [[Pancreatic polypeptide]] || PP || – || –
 |-
| Neuropeptide Y || [[Peptide YY]] || PYY || – || –
 |-
| [[Opioid]]s || [[Enkephalins]] ||   || [[Delta opioid receptor|δ-Opioid receptor]] || –
 |-
| Opioids || [[Dynorphins]] ||   || [[Kappa opioid receptor|κ-Opioid receptor]] || –
 |-
| Opioids || [[Neoendorphins]] ||   || [[Kappa opioid receptor|κ-Opioid receptor]] || –
 |-
| Opioids || [[Endorphins]] ||   || [[Mu opioid receptor|μ-Opioid receptor]]s || –
 |-
| Opioids || [[Endomorphins]] ||   || [[Mu opioid receptor|μ-Opioid receptor]]s || –
 |-
| Opioids || [[Morphine#Human biosynthesis|Morphine]] ||   || [[Mu opioid receptor|μ-Opioid receptor]]s || –
 |-
| Opioids || [[Nociceptin|Nociceptin/orphanin FQ]] || N/OFQ || [[Nociceptin receptor]]s || –
 |-
| [[Orexin]]s || [[Orexin A]] || OX-A || [[Orexin receptor]]s || –
 |-
| Orexins || [[Orexin B]] || OX-B || [[Orexin receptor]]s || –
 |-
| [[Parathyroid hormone family]] || [[Parathyroid hormone-related protein]] || PTHrP || – || –
 |-
| [[RFamide peptide family|RFamides]] || [[Kisspeptin]] || KiSS || [[GPR54]] || –
 |-
| RFamides || [[Neuropeptide FF]] || NPFF || NPFF1, NPFF2 || –
 |-
| RFamides || [[Prolactin-releasing peptide]] || PrRP|| [[Prolactin-releasing peptide receptor|PrRPR]] || –
 |-
| RFamides || [[Pyroglutamylated RFamide peptide]] || QRFP || [[Pyroglutamylated RFamide peptide receptor|GPR103]] || –
 |-
| [[Secretin family|Secretins]] || [[Secretin]] ||   || [[Secretin receptor]] || –
 |-
| Secretins || [[Motilin]] ||   || [[Motilin receptor]] || –
 |-
| Secretins || [[Glucagon]] ||   || [[Glucagon receptor]] || –
 |-
| Secretins || [[Glucagon-like peptide-1]] || GLP-1 || [[Glucagon-like peptide 1 receptor]] || –
 |-
| Secretins || [[Glucagon-like peptide-2]] || GLP-2 || [[Glucagon-like peptide 2 receptor]] || –
 |-
| Secretins || [[Vasoactive intestinal peptide]] || VIP || [[Vasoactive intestinal peptide receptor]]s || –
 |-
| Secretins || [[Growth hormone–releasing hormone]] || GHRH || [[Growth-hormone-releasing hormone receptor|Growth hormone–releasing hormone receptor]] || –
 |-
| Secretins || [[Pituitary adenylate cyclase-activating peptide]] || PACAP || [[ADCYAP1R1]] || –
 |-
| Somatostatins || [[Somatostatin]] ||  || [[Somatostatin receptor]]s || –
 |-
| [[Tachykinin peptides|Tachykinins]] || [[Neurokinin A]] ||   || – || –
 |-
| Tachykinins || [[Neurokinin B]] ||   || – || –
 |-
| Tachykinins || [[Substance P]] ||   || – || –
 |-
| Tachykinins || [[Neuropeptide K]] ||   || – || –
 |-
| Other || [[Agouti-related peptide]] || AgRP || [[Melanocortin receptor]] –
 |-
| Other || [[N-Acetylaspartylglutamate|''N''-Acetylaspartylglutamate]] || NAAG || [[Metabotropic glutamate receptor 3]] (mGluR3) || –
 |-
| Other || [[Cocaine- and amphetamine-regulated transcript]] || CART || Unknown [[Gi alpha subunit|G<sub>i</sub>/G<sub>o</sub>]]-coupled receptor<ref name="pmid21855138">{{cite journal | vauthors = Lin Y, Hall RA, Kuhar MJ | title = CART peptide stimulation of G protein-mediated signaling in differentiated PC12 cells: identification of PACAP 6-38 as a CART receptor antagonist | journal = Neuropeptides | volume = 45 | issue = 5 | pages = 351–8 | date = October 2011 | pmid = 21855138 | pmc = 3170513 | doi = 10.1016/j.npep.2011.07.006 }}</ref> || –
 |-
| Other || [[Gonadotropin-releasing hormone]] || GnRH|| [[gonadotropin-releasing hormone receptor|GnRHR]] || –
|-
| Other || [[Thyrotropin-releasing hormone]] || TRH|| [[Thyrotropin-releasing hormone receptor|TRHR]] || –
 |-
| Other || [[Melanin-concentrating hormone]] || MCH|| [[Melanin-concentrating hormone receptor|MCHR]] 1,2 || –
 |-
|}
{| class="wikitable sortable" style="width:100%"
|+ [[Gasotransmitter]]s
! scope="col" style="width: 15%;" | '''Category'''
! scope="col" style="width: 24%;" | '''Name'''
! scope="col" style="width: 6%;" class="unsortable" | <small>'''Abbreviation'''</small>
! scope="col" style="width: 31%;" | '''[[Metabotropic]]'''
! scope="col" style="width: 24%;" | '''[[Ionotropic]]'''
 |-
|[[Gaseous signaling molecule]] || [[Nitric oxide]] || NO || Soluble [[guanylyl cyclase]] || –
 |-
|Gaseous signaling molecule|| [[Carbon monoxide]] || CO || – || [[Heme]] bound to [[potassium channel]]s
 |-
|Gaseous signaling molecule|| [[Hydrogen sulfide]] || H2S || – || –
 |-
|}
|- <!--End of inner tables-->
|}