Glutamate

The insula, in red, is involved in pain and emotional response.. Dorling Kindersley/Getty Images

Definition:

Glutamate is a neurotransmitter normally involved in learning and memory. It is considered an excitatory neurotransmitter, which means it stimulates areas in the brain or other parts of the nervous system.

In some cases, however, it can become an excitotoxin, which means that it overstimulates brain cells to the point of killing them.

Glutamate, as an excitotoxin, is believed to be involved in a variety of neurodegenerative disorders including Alzheimer's disease and amyotrophic lateral sclerosis (known as ALS or Lou Gherig's disease).

Research shows that people with fibromyalgia have abnormally high levels of glutamate in the area of the brain called the insula (pictured), which is highly involved in pain and emotion. This is an indicator that this region may be chronically overstimulated. The insula also is involved in the senses, anxiety, motor skills, cravings, eating disorders, and addiction, many of which can are related to fibromyalgia.

Studies are divided as to whether glutamate dysregulation plays a role in chronic fatigue syndrome, which also involves many of the symptoms listed above.

As an amino acid, glutamate is a component of monosodium glutamate (MSG), which is used in pharmaceuticals and as a food additive. Some health-care practitioners believe MSG can be harmful to people with fibromyalgia, while others believe it is not. Some people say that eliminating MSG from their diets has helped alleviate symptoms of fibromyalgia and chronic fatigue syndrome, but these claims are not substantiated by medical science.

In the brain, glutamate is balanced by another neurotransmitter called GABA.

Other neurotransmitters involved in these conditions include:

Pronunciation: GLOO-ta-mate

Also Known As: L-glutamic acid, glutamic acid, L-glutamate

Hannestad U, Theodorsson E, Evengård B. International journal of clinical chemisty. 2007 Feb;376(1-2):23-9. Epub 2006 Jul 14. beta-Alanine and gamma-aminobutyric acid in chronic fatigue syndrome.

Harris RE, et. al. Arthritis and rheumatism. 2009 Oct;60(10):3146-52. Elevated insular glutamate in fibromyalgia is associated with experimental pain.

Harris RE, et. al. Arthritis and rheumatism. 2008 Mar;58(3):903-7. Dynamic levels of glutamate within the insula are associated with improvements in multiple pain domains in fibromyalgia.

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