Icilin         Names       Preferred IUPAC name  3-(2-Hydroxyphenyl)-6-(3-nitrophenyl)-3,4-dihydropyrimidin-2(1H )-one
      Other names 1-(2-Hydroxyphenyl)-4-(3-nitrophenyl)-3,6-dihydropyrimidin-2-one AG-3-5
     Identifiers                           ChemSpider          ECHA InfoCard     100.164.593                            UNII                    InChI=1S/C16H13N3O4/c20-15-7-2-1-6-14(15)18-9-8-13(17-16(18)21)11-4-3-5-12(10-11)19(22)23/h1-8,10,20H,9H2,(H,17,21)
 N  Key: RCEFMOGVOYEGJN-UHFFFAOYSA-N
 N  InChI=1/C16H13N3O4/c20-15-7-2-1-6-14(15)18-9-8-13(17-16(18)21)11-4-3-5-12(10-11)19(22)23/h1-8,10,20H,9H2,(H,17,21)
Key: RCEFMOGVOYEGJN-UHFFFAOYAQ
         O=C3N(c1c(O)cccc1)C/C=C(/c2cccc([N+]([O-])=O)c2)N3
       Properties        C16 H13 N3 O4       Molar mass    311.29 g/mol                 Except where otherwise noted, data are given for materials in their 
standard state  (at 25 °C [77 °F], 100 kPa).
   Infobox references
    
 Icilin  (AG-3-5 ) is a synthetic  super-agonist  of the transient receptor potential M8  (TRPM8) ion channel . Although structurally not related to menthol , it produces an extreme sensation of cold, both in humans and animals. It is almost 200 times more potent than menthol, and 2.5 times more efficacious.[ 1]   Despite their similar effects, icilin activates the TRPM8 receptor in a different way than menthol does.[ 2]   Icilin has been shown to be effective in the treatment of pruritus  in an experimental model of itch.[ 3]   It is now used as a research tool for the study of TRP channels , although despite its high potency it is less selective for TRPM8 over other related ion channels than are other compounds such as WS-12 . 
 
References    ^   Wei ET, Seid DA (1983). "AG-3-5: a chemical producing sensations of cold". J. Pharm. Pharmacol . 35  (2): 110– 2. doi :10.1111/j.2042-7158.1983.tb04279.x . PMID  6131976 . S2CID  42844929 .     ^   Andersson DA, Chase HW, Bevan S (2004). "TRPM8 activation by menthol, icilin, and cold is differentially modulated by intracellular pH" . J. Neurosci . 24  (23): 5364– 9. doi :10.1523/JNEUROSCI.0890-04.2004  . PMC  6729305  . PMID  15190109 .     ^   Biró, T; Ko, MC; Bromm, B; et al. (2005). "How best to fight that nasty itch - from new insights into the neuroimmunological, neuroendocrine, and neurophysiological bases of pruritus to novel therapeutic approaches" . Experimental Dermatology . 14  (3): 225– 40. doi :10.1111/j.0906-6705.2005.0321a.x  . PMID  15740597 . S2CID  23665244 .        
External links  
TRPA 
Activators  4-Hydroxynonenal   4-Oxo-2-nonenal   5,6-EET   12S-HpETE   15-Deoxy-Δ12,14 -prostaglandin J2   α-Sanshool  (ginger , Sichuan  and melegueta peppers )  Acrolein   Allicin  (garlic )  Allyl isothiocyanate  (mustard , radish , horseradish , wasabi )  AM404   ASP-7663   Bradykinin   Cannabichromene  (cannabis )  Cannabidiol  (cannabis )  Cannabigerol  (cannabis )  Cinnamaldehyde  (cinnamon )  CR gas (dibenzoxazepine; DBO)   CS gas (2-chlorobenzal malononitrile)   Cuminaldehyde  (cumin )  Curcumin  (turmeric )  Dehydroligustilide (celery )  Diallyl disulfide   Dicentrine  (Lindera   spp.)  Farnesyl thiosalicylic acid  Formalin   Gingerols  (ginger )  Hepoxilin A3   Hepoxilin B3   Hydrogen peroxide     Isothiocyanate   JT-010   Ligustilide  (celery , Angelica acutiloba  )  Linalool  (Sichuan pepper , thyme )  Methylglyoxal   Methyl salicylate  (wintergreen )  N-Methylmaleimide   Nicotine  (tobacco )  Oleocanthal  (olive oil )  Paclitaxel  (Pacific yew )  Paracetamol (acetaminophen)   PF-4840154   Phenacyl chloride   Polygodial  (Dorrigo pepper )  Shogaols  (ginger , Sichuan  and melegueta peppers )  Tear gases   Tetrahydrocannabinol  (cannabis )  Tetrahydrocannabiorcol   Thiopropanal S-oxide  (onion )  Umbellulone  (Umbellularia californica )  WIN 55,212-2    Blockers 
TRPC 
TRPM 
TRPML 
TRPP 
TRPV 
Activators  2-APB   5,6-EET   9-HODE   9-oxoODE   12S-HETE   12S-HpETE   13-HODE   13-oxoODE   20-HETE   α-Sanshool  (ginger , Sichuan  and melegueta peppers )  Allicin  (garlic )  AM404   Anandamide   Bisandrographolide (Andrographis paniculata  )  Camphor  (camphor laurel , rosemary , camphorweed , African blue basil , camphor basil )  Cannabidiol  (cannabis )  Cannabidivarin  (cannabis )  Capsaicin  (chili pepper )  Carvacrol  (oregano , thyme , pepperwort , wild bergamot , others)  DHEA   Diacyl glycerol   Dihydrocapsaicin  (chili pepper )  Estradiol   Eugenol  (basil , clove )  Evodiamine  (Euodia ruticarpa  )  Gingerols  (ginger )  GSK1016790A   Heat   Hepoxilin A3   Hepoxilin B3   Homocapsaicin  (chili pepper )  Homodihydrocapsaicin  (chili pepper )  Incensole  (incense )  Lysophosphatidic acid   Low pH  (acidic conditions)  Menthol  (mint )  N-Arachidonoyl dopamine   N-Oleoyldopamine  N-Oleoylethanolamide   Nonivamide (PAVA)  (PAVA spray )  Nordihydrocapsaicin  (chili pepper )  Paclitaxel  (Pacific yew )  Paracetamol (acetaminophen)   Phenylacetylrinvanil   Phorbol esters  (e.g., 4α-PDD)  Piperine  (black pepper , long pepper )  Polygodial  (Dorrigo pepper )  Probenecid   Protons   RhTx   Rutamarin (Ruta graveolens  )  Resiniferatoxin  (RTX) (Euphorbia resinifera /pooissonii  )  Shogaols  (ginger , Sichuan  and melegueta peppers )  Tetrahydrocannabivarin  (cannabis )  Thymol  (thyme , oregano )  Tinyatoxin  (Euphorbia resinifera /pooissonii  )  Tramadol   Vanillin  (vanilla )  Zucapsaicin    Blockers 
See also:  Receptor/signaling modulators • Ion channel modulators