1-Methylhistamine

1-Methylhistamine
Identifiers
CAS Number	501-75-7;
3D model (JSmol)	Interactive image;
Beilstein Reference	110757
ChEBI	CHEBI:29009;
ChEMBL	ChEMBL507;
ChemSpider	3488;
Gmelin Reference	2906
KEGG	C05127;
PubChem CID	3614;
UNII	KCB81T4EOF;
CompTox Dashboard (EPA)	DTXSID30198207 ;
	InChI InChI=1S/C6H11N3/c1-9-4-6(2-3-7)8-5-9/h4-5H,2-3,7H2,1H3 Key: FHQDWPCFSJMNCT-UHFFFAOYSA-N;
	SMILES CN1C=C(N=C1)CCN;
Properties
Chemical formula	C6H11N3
Molar mass	125.175 g·mol−1
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314, H317, H334, H335
Precautionary statements	P233, P260, P261, P264, P271, P272, P280, P284, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P319, P321, P333+P317, P342+P316, P362+P364, P363, P403, P403+P233, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

1-Methylhistamine (also known as N^τ-methylhistamine (NMH)) is a metabolite of histamine.

Background

NMH is formed by N^τ-methylation of histamine, catalyzed by the enzyme Histamine N-methyltransferase.

NMH is excreted in the urine and can be measured as a biomarker of histamine activity.^[2] While NMH has some biological activity on its own, it is much weaker than histamine. It can bind to histamine receptors, still, NMH has a lower affinity and efficacy than histamine for these receptors, meaning that it binds less strongly and activates them less effectively. Depending on the receptor subtype and the tissue context, NMH may act as a partial agonist or an antagonist for some histamine receptors. NMH may have some modulatory effects on histamine signalling, but it is unlikely to cause significant allergic or inflammatory reactions by itself. NMH may also serve as a feedback mechanism to regulate histamine levels and prevent excessive histamine release.^[3]

In clinical settings, urinary NMH can be measured when systemic mastocytosis is suspected. Systemic mastocytosis and anaphylaxis are typically associated with at least a two-fold increase in urinary NMH levels, which are also increased in patients taking monoamine oxidase inhibitors and in patients on histamine-rich diets.^[2]

References

^ "1-Methylhistamine". pubchem.ncbi.nlm.nih.gov. Archived from the original on 8 December 2022. Retrieved 28 November 2023.
^ ^a ^b Lewiecki EM (2013). "Evaluation of the Patient at Risk for Osteoporosis". Chapter 63 - Evaluation of the Patient at Risk for Osteoporosis. pp. 1481–1504. doi:10.1016/B978-0-12-415853-5.00063-7. ISBN 9780124158535.
^ Shahid M, Tripathi T, Khan RA, Khardori N, Al-Sultan AI, Al-Mohammed HI, Alsultan AA, Huq A, Khan AA, Siddiqui M (2010). "Biological and Pharmacological Aspects of Histamine Receptors and Their Ligands". Biomedical Aspects of Histamine. pp. 61–100. doi:10.1007/978-90-481-9349-3_4. ISBN 978-90-481-9348-6.

[1] "1-Methylhistamine". pubchem.ncbi.nlm.nih.gov. Archived from the original on 8 December 2022. Retrieved 28 November 2023.

[doi10.1016/B978-0-12-415853-5.00063-7-2] Lewiecki EM (2013). "Evaluation of the Patient at Risk for Osteoporosis". Chapter 63 - Evaluation of the Patient at Risk for Osteoporosis. pp. 1481–1504. doi:10.1016/B978-0-12-415853-5.00063-7. ISBN 9780124158535.

[10.1007/978-90-481-9349-3_4-3] Shahid M, Tripathi T, Khan RA, Khardori N, Al-Sultan AI, Al-Mohammed HI, Alsultan AA, Huq A, Khan AA, Siddiqui M (2010). "Biological and Pharmacological Aspects of Histamine Receptors and Their Ligands". Biomedical Aspects of Histamine. pp. 61–100. doi:10.1007/978-90-481-9349-3_4. ISBN 978-90-481-9348-6.

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