Which substance do mast cells release to combat allergies?

Mast cells play a crucial role in the immune response, particularly in allergic reactions. They release histamine, which is a key mediator that contributes to the symptoms associated with allergies. When an allergen enters the body, mast cells detect it and activate, leading to the degranulation process where histamine is released into the surrounding tissues. This release causes various physiological effects such as vasodilation, increased blood vessel permeability, and stimulation of nerve endings, which manifest as typical allergy symptoms like itching, swelling, and redness.

While cytokines, serotonin, and prostaglandins are also involved in immune responses and various physiological processes, histamine is specifically recognized for its primary role in the immediate hypersensitivity reactions that characterize allergies. It directly contributes to the acute symptoms seen in allergic responses, making it the fundamental substance that mast cells release during such events.