Histamine is a heterocyclic primary amine derived from decarboxylation of the amino acid histidine. It is a mediator of inflammation closely associated with the initial phase of immediate hypersensitivity response (anaphylaxis). Histamine is synthesized by the enzyme histidine decarboxylase and is present in most cells, but typically stored in metachromatic granules of basophils and mast cells (granulocytes). Histamine in the intracellular granules is bound to proteins and inactive until it is released from the cells.
During anaphylactic response, an antigen-IgG antibody complex formed in vivo activates the complement cascade and cleaves bioactive complement associated peptides called anaphylatoxins. Among anaphylatoxins, C3a, which is derived from the complement component C3, and C5a derived from C5 releases histamine from mast cells. In IgE-mediated immediate hypersensitivity response, an IgE antibody is produced by B lymphocytes upon stimulation by an allergen and under the control of IL-13 and IL-4. Such IgE antibodies are secreted from B lymphocytes and bound to a high affinity receptor (FcεRI High binding IgE receptor) on mast cells in the tissue or on basophilic leukocytes in the peripheral blood leukocytes. When IgE bearing mast cells or basophils encounter allergen to which the IgE antibody was directed, the allergen (antigen) binds to the cell bound IgE and agglutinates on the surface of these cells. This event triggers the release of granules into the blood stream. Degranulation of the mast cell involves release of mediators such as leukotriene C4/D4/E4, thromboxane A2, PGD2, Platelet Activating Factor, histamine, heparin, tryptase, kallikrein, ECF-A, IL-8 and other cytokines. Histamine released from mast cell acts on smooth muscle and blood vessels, causing bronchoconstriction, vasodilation and increased vascular permeability (erythema).
Histamine exerts its biological effects through four distinct receptors on various tissues and cells; H1, H2, H3 and H4. Among these histamine receptors, H2 receptor is best recognized as associated with secretion of acid in the stomach leading to peptic ulcer. Thus, an H2 receptor antagonist is used for treatment of peptic ulcers.
Tissue bound mast cells (such as in the skin, nasal mucosa) respond to incoming allergen and manifest as erythema (e.g. in skin test) and wheezing response. In various research areas, it is important to study in vitro histamine release from peripheral blood basophils. When whole blood from a sensitized animal is exposed to a given allergen, basophils respond to the allergen by releasing histamine into the incubation mixture. Using a whole blood sample, one can assess ex vivo response to a sensitizing antigen as a function of histamine released from the basophils.
Other than histamine being an important mediator of immediate hypersensitivity, histamine is found in decaying fish meat, especially of scombroid fish such as tuna. For this reason histamine is called “Scombrotoxin”. Histamine is also found in wine and cheese. Neogen's histamine kit is a leading histamine ELISA test kit used in a variety of applications.
Standard Curve in EIA Buffer
|Product #||Product Description|
|409010||Histamine Kit, 96 well kit|
Kit inserts available on our website are for reference use only and are subject to change. It is always recommended to use the protocol included with the kit.
For research use only.