Allergy symptoms are mostly caused by the release of histamine in response to allergens. The binding of histamine to the extracellular portion of the H1 receptor triggers a structural change of the transmembrane portion, leading to a change in the C terminal area. This c terminal region interacts with G proteins, leading to the activation of the Gq signalling pathway, which triggers allergy symptoms like itchy eyeys and runny noses. Many allergy drugs are anti-histamines, in that they bind to the histamine receptor but do not cause the conformational change that leads to a response.
Structural highlights
The structure of the H1 histamine receptor bound to an antihistamine, doxepin was published in 2011 [1].
