:Gamma-Aminobutyric Acid, Glutamic Acid & Glutamine:

Function: neurotransmitters.

Glutamic Acid (GA) is a nonessential amino acid which can normally be synthesized in the body from many substances, i.e., alpha ketoglutarate, ornithine, arginine, proline, or Glutamine (GAM). GA is used to make proteins, peptides (glutathione), amino acids (proline, histidine, GAM, and GABA) and DNA. GA, GABA (gamma-aminobutyric acid) and GAM are all neurotransmitters in the brain. GA is excitatory and GABA inhibitory. GAM is primarily a brain fuel. Vitamin B6 and manganese increase the amount of GABA made from GA. Aspartic acid is an excitatory neurotransmitter that is competitively transported with GA, whereas taurine and glycine are inhibitory neurotransmitters that are competitively transported with GABA.

GA and GAM are extremely abundant amino acids. GA is the second most concentrated in the brain and GAM is not far behind. GAM is the most abundant amino acid in blood. GA is the most abundant in food; about 7 grams are contained in a cup of cottage cheese and as much as 13 grams in a pound of pork.

Initial studies with GA using 10 to 12 g in mentally retarded individuals were found to raise IQ. Doses of GABA 1 to 3 g orally also have been used effectively to raise IQ of mentally retarded persons.

Initial studies in alcoholics using a daily dose of 10 to 15 g of L-GAM were effective in controlling this addiction.

GAM is a major fuel for the brain, but also for lymphocytic cancer cells. An enzyme which destroys GAM is useful in acute leukemia and other cancers, Some effects of the excessive breakdown of GAM are infertility, depression, abdominal cramps, headache, weight loss, anorexia, increased blood ammonia and, rarely, a Parkinson's syndrome. Other deficiencies of the glutamate family of neurotransmitters relate to the metabolism of glutathione.

GA given as MSG can produce a seizure-like disorder in infants. In contrast, various drugs that inhibit GA, aspartic acid and metabolites are effective anticonvulsants. GABA is found to be deficient in cerebrospinal fluid and brain in many studies of experimental and human epilepsy. Benzodiazepines (such as Valium) are useful in status epilepticus because they act on GABA receptors. GABA increases in the brain after administration of many seizure medications. Hence, GABA is clearly an antiepileptic nutrient, while the data is mixed regarding GA. Inhibitors of GAM metabolism can also produce convulsions.

Spasticity and involuntary movement syndromes, e.g., Parkinson's, Friedreich's ataxia, tardive dyskinesia, and Huntington's chorea are all marked by low GABA when amino acid levels are studied. Trials of 2 to 3 g of GABA given orally have been effective in various epilepsy and spasticity syndromes.

Agents that elevate GABA also are useful in lowering hypertension. Three grams orally have been effective in control of blood pressure. GABA is decreased and GA is increased in various encephalopathies. GABA can reduce appetite and is decreased in hypoglycemia. GABA reduces blood sugar in diabetis. Chronic brain syndromes can also be marked by deficiency of GABA, as well as of GA and GAM. GABA has many promising uses in therapy.

There may be therapeutic uses of GA and GAM, but GABA has the most therapeutic potential of the three. GABA levels are difficult to detect in plasma and urine, while GAM and GA are easily measured. GABA therapy should be considered when GA is elevated and GAM is deficient. Cerebrospinal fluid levels of GABA may be useful in diagnosing very serious diseases. Vitamin B6, manganese, taurine and lysine can increase both GABA synthesis and effects, while aspartic acid and GA probably inhibit GABA effects.