H2 Histamine Receptor Antibodies

The histamine H₂ receptor (H₂R), encoded by HRH2, is a class A G protein-coupled receptor activated by the endogenous biogenic amine histamine. It couples predominantly to Gs, stimulating adenylyl cyclase and increasing intracellular cAMP and protein kinase A activity. H₂R is expressed on gastric parietal cells and is also found in the heart, brain, and several immune cell populations. In gastric parietal cells, its activation promotes acid secretion by stimulating the H⁺/K⁺-ATPase. H₂R signaling can also modulate cardiac activity and immune cell responses. Sustained agonist exposure induces receptor desensitization and internalization, with β-arrestins, dynamin, and clathrin contributing to trafficking in experimental systems. Internalized receptors can undergo dephosphorylation and recycle to the cell surface, restoring responsiveness to histamine. Approved H₂ receptor blockers, including famotidine and cimetidine, suppress gastric acid secretion and are used to treat acid-related disorders such as gastroesophageal reflux and peptic ulcer disease. These drugs can exhibit inverse agonism, reducing constitutive receptor activity in addition to blocking histamine-induced signaling. The H2 receptor is phosphorylated at Serine319/Ser322 (pS319/pS322-H2) in an agonist dependent manner.

For more information on histamine receptor pharmacology please refer to the IUPHAR database. For further reading refer to:

Chazot P, Cowart M, Fukui H, Ganellin CR, Gutzmer R, Haas HL, Hill SJ, Hills R, Leurs R, Levi R, Liu S, Panula P, Schunack W, Schwartz JC, Seifert R, Shankley NP, Stark H, Thurmond R, Timmerman H, Young JM. Histamine receptors in GtoPdb v.2023.1. IUPHAR/BPS Guide to Pharmacology CITE. 2023; 2023(1). Available from: https://doi.org/10.2218/gtopdb/F33/2023.1.