What is Histamine?

Histamine is a chemical produced by the body. It is stored in two kinds of cells. It is found in basophil cells which are white blood cells. It is also found in mast cells which are tissue cells. Mast cells can be found around the:

• eyes
• nose
• lungs
• gastrointestinal tract
• skin

If you were to look at a mast cell under a microscope, the inside would look very grainy. Below is a picture of a mast cell. All of the inflammatory chemicals look like granules and when the mast cell burst open, it is called; degranulation.

Image courtesy of Wikipedia

The granules are tiny storage compartments containing many different kinds of inflammatory chemicals. These chemicals are used by the immune system to protect the body from foreign invaders.

Most people are aware of the release of histamine during an allergic reaction. They produce the symptoms that we know as allergy symptoms such as congestion, runny nose, sneezing, and watery eyes. Apart from nasal allergies, they play a role that is important to our bodies. We need this chemical for good health because it;

• stimulates stomach acids
• promotes swelling which aids in healing
• is important in the regulation of sleep
• enhances saliva and pancreatic secretions
• aid in the production of mucus which plays a vital role in our health

The role that we are the most familiar with is the role that it plays during an allergic reaction.

When an allergen enters the body, the immune system produces antibodies to fight off the non-self particles. The antibodies send a signal to the mast cells to activate them. This activation causes them to burst open. This process is called degranulation. The granules inside the mast cells release the chemicals that they are storing. These inflammatory chemicals affect the body in several ways to prevent more allergens from entering and to expel what allergens have managed to enter.

You can learn more about histamine by going to the Davidson College website that has an article written by an undergraduate student.

Histamine

This potent chemical produced by our own bodies:

• Make smooth muscles to contract. It might be noted that this can be dangerous for those with asthma because it can also happen in the bronchial tubes. The diameter of the airway to the lungs becomes smaller making it more difficult to breathe.
• Make blood vessels become more permeable. This allows fluid to leak out of the capillaries into the surrounding area resulting in swelling. The dilation of the blood vessels causes redness.
• Increases the blood flow to the tissue which will cause them to swell and to turn the skin red.
• Irritates the nerve ending which cause the skin to itch.
• In excessive amounts can cause an anaphylaxis reaction.

Histamine looks for the receptors on cells that can receive them. They fit together perfectly. When this happens, the process of producing the allergic symptoms begin. Because antihistamines mimic the molecular structure, they also fit into the same receptors on the body's cells. By reaching these receptors first, they prevent the inflammatory chemical from having any place to go.

You can learn more about histamine by going to the Davidson College website that has an article written by an undergraduate student.

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