Anti-Histamine H₁ Receptor/HRH1 (extracellular) Antibody

Histamine, acts via distinct histamine H1, H2, H3, and H4 receptors, and regulates various physiological and pathological processes. Hence the activity of Histamine receptors is very crucial. They are members of G-protein coupled receptors superfamily. Thus, have seven transmembrane domains, extracellular N-terminal tail and a cytoplasmic C-terminus¹.

H1 receptor is excitatory and couples to Gq‐type proteins, activating a signaling cascade which eventually leads to an increased cellular concentration of Ca^{2+ 3}.

H1 receptor is implicated in type I hypersensitivity allergic reactions caused by numerous allergens¹. An allergic reaction occurs when allergens activate mast cells that release histamine, the released histamine binds to H1R and this causes an activation of a cascade that leads to vasodilation and vascular hyper-permeability, resulting in allergic inflammation.

H₁R is expressed in various tissues throughout body, including the airway, vascular smooth muscle, and brain². H₁R expressed in the brain plays an important role in the regulation of sleep-arousal cycle and memory by binding histamine where it acts as a neurotransmitter¹.