What molecule am I?
Histamine is an organic triamine that is a strong vasodilator found in blood and most bodily tissues. It is involved in inflammatory and immune responses. Histamine is stored primarily in mast cells and basophils; it is released in response to tissue damage caused by injury, infection, or allergens.
In 1938, French microbiologists L茅vy-Br眉hl and Ungar showed that pneumococcus bacteria and Balantidium coli biosynthesize histamine from the amino acid histidine. It was later shown that this reaction is catalyzed by the enzyme histidine decarboxylase.
Histamine has many physiological functions, but this time of year we focus on its role in reactions to allergens such as pollen. Allergens bind to the antibody immunoglobulin E in the mucous membranes of the nasal cavity, releasing histamine, and leading to runny noses, watery eyes, sneezing, and nasal congestion. Fortunately, many antihistamines are available to combat these symptoms.
Histamine hazard information
| GHS classification*: acute toxicity, oral, category 3聽 | |
| H301鈥擳oxic if swallowed |  |
| GHS classification: skin irritation, category 2聽 | |
| H315鈥擟auses skin irritation聽 |  |
| GHS classification: skin sensitization, category 1 | |
| H317鈥擬ay cause an allergic skin reaction | |
| GHS classification: eye irritation, category 2A | |
| H319鈥擟auses serious eye irritation | |
| GHS classification: respiratory sensitisation, category 1 | |
H334鈥擬ay cause allergy or asthma symptoms or breathing difficulties if inhaled |  |
| GHS classification: specific target organ toxicity, single exposure, category3 | |
| H335鈥擬ay cause respiratory irritation | |
*Globally Harmonized System of Classification and Labeling of Chemicals.聽.
Histamine fast facts
| CAS Reg. No. | 51-45-6 |
| Molar mass | 111.15 g/mol聽 |
| Empirical formula | C5H9N3 |
| Appearance | White crystals or powder |
| Melting point | 83鈥�84 潞C |
| Water solubility | 34 g/L |
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