There are four types of histamine receptor: H1, H2, H3 and H4. The binding of histamine to these receptors stimulates them to produce functional responses and these are described in more detail ...

The most well-researched histamine receptors are H1 and H2, with less known about the effects that histamine has on H3 and H4. Capillaries dilate and become more permeable, which can cause facial ...

each involving different histamine receptors called H1, H2, H3, and H4. The H1 receptor is found mostly in the inner surface of blood and lymphatic vessels, neurons, and smooth muscle cells.

There are four broad classes⁠ of antihistamines—H1, H2, H3, and H4—classified by the type of histamine receptor they bind to. The type most commonly used for allergies is H1-antihistamines ...