HRH2
Identifiers
AliasesHRH2, H2R, histamine receptor H2, HH2R
External IDsOMIM: 142703 MGI: 108482 HomoloGene: 40613 GeneCards: HRH2
Gene location (Human)
Chromosome 5 (human)
Chr.Chromosome 5 (human)[1]
Chromosome 5 (human)
Genomic location for HRH2
Genomic location for HRH2
Band5q35.2Start175,658,030 bp[1]
End175,710,756 bp[1]
RNA expression pattern
PBB GE HRH2 220805 at fs.png
More reference expression data
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001131055
NM_022304
NM_001367711

NM_001010973
NM_008286

RefSeq (protein)

NP_001124527
NP_001354640

NP_001010973

Location (UCSC)Chr 5: 175.66 – 175.71 MbChr 13: 54.19 – 54.24 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

H2 receptors are positively coupled to adenylate cyclase via Gs. It is a potent stimulant of cAMP production, which leads to activation of protein kinase A.[5] PKA functions to phosphorylate certain proteins, affecting their activity. The drug betazole is an example of a histamine H2 receptor agonist.

Function[edit]

Histamine is a ubiquitous messenger molecule released from mast cells, enterochromaffin-like cells, and neurons.[5] Its various actions are mediated by histamine receptors H1, H2, H3 and H4. The histamine receptor H2 belongs to the rhodopsin-like family of G protein-coupled receptors. It is an integral membrane protein and stimulates gastric acid secretion. It also regulates gastrointestinal motility and intestinal secretion and is thought to be involved in regulating cell growth and differentiation.[6]

Tissue distribution[edit]

Histamine H2 receptors are expressed in the following tissues:

Peripheral tissues[5][7]
Central nervous system tissues[7]

Physiological responses[edit]

Activation of the H2 receptor results in the following physiological responses:

  • Stimulation of gastric acid secretion (Target of anti-histaminergics (H2 receptors) for peptic ulcer disease and GERD)
  • Smooth muscle relaxation (Experimental histamine H2 receptor agonist used for asthma and COPD)
  • Inhibit antibody synthesis, T-cell proliferation and cytokine production
  • VasodilationPKA activity causes phosphorylation of MLCK, decreasing its activity, resulting in MLC of myosin being dephosphorylated by MLCP and thus inhibiting contraction. The smooth muscle relaxation leads to vasodilation.[8]
  • Inhibition of neutrophil activation and chemotaxis[7]

See also[edit]

References[edit]

  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000113749 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000034987 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ a b c Hill SJ, Ganellin CR, Timmerman H, Schwartz JC, Shankley NP, Young JM, Schunack W, Levi R, Haas HL (Sep 1997). "International Union of Pharmacology. XIII. Classification of histamine receptors". Pharmacological Reviews. 49 (3): 253–78. PMID 9311023.
  6. ^ "Entrez Gene: HRH2 histamine receptor H2".
  7. ^ a b c Maguire JJ, Davenport AP (29 November 2016). "H2 receptor". IUPHAR/BPS Guide to PHARMACOLOGY. International Union of Basic and Clinical Pharmacology. Retrieved 20 March 2017.
  8. ^ Walter F., PhD. Boron (2005). Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. ISBN 1-4160-2328-3. Page 479

Further reading[edit]

External links[edit]

This article incorporates text from the United States National Library of Medicine, which is in the public domain.