Histamine receptors in GtoPdb v.2023.1

Abstract

Histamine receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Histamine Receptors [80, 174]) are activated by the endogenous ligand histamine. Marked species differences exist between histamine receptor orthologues [80]. The human and rat H₃ receptor genes are subject to significant splice variance [12]. The potency order of histamine at histamine receptor subtypes is H₃ = H₄ > H₂ > H₁ [174]. Some agonists at the human H₃ receptor display significant ligand bias [183]. Antagonists of all 4 histamine receptors have clinical uses: H₁ antagonists for allergies (e.g. cetirizine), H₂ antagonists for acid-reflux diseases (e.g. ranitidine), H₃ antagonists for narcolepsy (e.g. pitolisant/WAKIX; Registered) and H₄ antagonists for atopic dermatitis (e.g. adriforant; Phase IIa) [174] and vestibular neuritis (AUV) (SENS-111 (Seliforant, previously UR-63325), entered and completed vestibular neuritis (AUV) Phase IIa efficacy and safety trials, respectively) [217, 8].