Question

How many types of histamine receptors are present in the body?

Options

• Four types: H1, H2, H3, and H4

• Three types: H1, H2, and H3

• One type: H1 only

• Two types: H1 and H2

Answer 1

There are two types of histamine receptors in the body: H1 and H2. Each receptor type has distinct tissue distributions and physiological effects. H1 receptors are involved in allergic manifestations, while H2 receptors are involved in gastric acid secretion. This distinction is critical for understanding both the symptoms of allergies and the mechanism of action of antihistamine drugs.