What is the role of histamines in allergy responses?

Histamines are responsible for the symptoms of allergy responses, including itching, swelling, and inflammation.

When an allergen enters the body, it triggers the release of histamines from mast cells and basophils. Histamines bind to receptors on blood vessels, causing them to dilate and become more permeable. This allows immune cells to enter the affected tissue, leading to inflammation and swelling.

Histamines also stimulate nerve endings, causing itching and pain. In the respiratory system, histamines can cause constriction of the airways, leading to difficulty breathing.

Antihistamines work by blocking the histamine receptors, preventing the histamines from causing symptoms. However, they do not prevent the release of histamines, so they are most effective when taken before exposure to an allergen.

In addition to their role in allergy responses, histamines also play a role in other physiological processes, such as regulating stomach acid secretion and neurotransmitter release in the brain.

Overall, histamines are a key player in the symptoms of allergy responses, and understanding their role can help in developing effective treatments for allergies.