Histamine receptor

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:

  • H1 receptor H1 Receptors: These receptors are primarily located on smooth muscle cells, endothelial cells, and neurons. Activation of H1 receptors mediates various responses, including smooth muscle contraction (leading to bronchoconstriction, intestinal cramping), increased vascular permeability (resulting in edema), and stimulation of sensory nerve endings (causing itching and pain). H1 antagonists, commonly known as antihistamines, are used to alleviate symptoms of allergies and allergic reactions.[3]
  • H2 receptor H2 Receptors: Found mainly in the stomach lining (parietal cells), H2 receptors regulate gastric acid secretion by stimulating the production of hydrochloric acid. H2 antagonists (H2 blockers) are used to reduce stomach acid production and treat conditions like gastroesophageal reflux disease (GERD) and peptic ulcers.[3]
  • H3 receptor H3 Receptors: These receptors are predominantly located in the central nervous system (CNS), particularly in regions associated with neurotransmitter release and modulation. H3 receptors act as presynaptic autoreceptors and heteroreceptors, regulating the release of neurotransmitters such as dopamine, serotonin, norepinephrine, and acetylcholine. Modulation of H3 receptors is being explored as a potential target for various neurological and psychiatric disorders.[4]
  • H4 receptor H4 Receptors: Initially discovered on immune cells, particularly mast cells, eosinophils, and T cells, H4 receptors are involved in immune responses, including chemotaxis (cellular movement in response to chemical signals) and cytokine production. These receptors play a role in inflammation and allergic reactions. Research on H4 receptors is ongoing to better understand their involvement in immune-related disorders and to develop potential therapeutic interventions.[5]
  1. ^ Hill SJ, Ganellin CR, Timmerman H, Schwartz JC, Shankley NP, Young JM, et al. (September 1997). "International Union of Pharmacology. XIII. Classification of histamine receptors". Pharmacological Reviews. 49 (3): 253–278. PMID 9311023.
  2. ^ Ravhe IS, Krishnan A, Manoj N (January 2021). "Evolutionary history of histamine receptors: Early vertebrate origin and expansion of the H3-H4 subtypes". Molecular Phylogenetics and Evolution. 154: 106989. doi:10.1016/j.ympev.2020.106989. PMID 33059072. S2CID 222842322.
  3. ^ a b Simons FE (November 2004). "Advances in H1-antihistamines". The New England Journal of Medicine. 351 (21): 2203–2217. doi:10.1056/NEJMra033121. PMID 15548781.S
  4. ^ Haas H, Panula P (February 2003). "The role of histamine and the tuberomamillary nucleus in the nervous system". Nature Reviews. Neuroscience. 4 (2): 121–130. doi:10.1038/nrn1034. PMID 12563283. S2CID 31148156.
  5. ^ Oda T, Morikawa N, Saito Y, Masuho Y, Matsumoto S (November 2000). "Molecular cloning and characterization of a novel type of histamine receptor preferentially expressed in leukocytes". The Journal of Biological Chemistry. 275 (47): 36781–36786. doi:10.1074/jbc.M006480200. PMID 10973974.