The histamine receptors are a class of G protein–coupled receptors which bind histamine as their primary endogenous ligand.[1][2]
Histamine receptors are proteins that bind with histamine, a neurotransmitter involved in various physiological processes. There are four main types: H1, H2, H3, and H4. H1 receptors are linked to allergic responses, H2 to gastric acid regulation, H3 to neurotransmitter release modulation, and H4 to immune system function.
There are four known histamine receptors:
| Receptor | Location | Mechanism of action | Function | Antagonists | Uses of antagonists |
|---|---|---|---|---|---|
| H1 | Throughout the body, especially in:[6]
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Gq |
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| H2 |
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Gs ↑ cAMP2+ |
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| H3 |
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Gi |
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| H4 | Gi |
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As of July 2021[update], no clinical uses exist. Potential uses include:[9]
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There are several splice variants of H3 present in various species. Though all of the receptors are 7-transmembrane g protein coupled receptors, H1 and H2 are quite different from H3 and H4 in their activities. H1 causes an increase in PIP2 hydrolysis, H2 stimulates gastric acid secretion, and H3 mediates feedback inhibition of histamine.
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