Do salt cravings in children with autistic disorders reveal low blood sodium depleting brain taurine and glutamine?

Because boys are four times more likely than girls to develop autism, the role of male hormones (androgens) has received considerable scrutiny. Some researchers implicate arginine vasopressin, an androgen-dependent hormone from the pituitary gland that elicits male behavior. Elevated vasopressin is also the most common cause of low blood sodium (hyponatremia)--most serious in the brains of children. Hyponatremia causes astrocytes to swell, then release the amino acids taurine and glutamine and their water to compensate. Taurin--the brain osmolyte/inhibitory neurotransmitter that suppresses vasopressin--was the amino acid most wasted or depleted in urine of autistic children. Glutamine is a critical metabolic fuel in brain neurons, astrocytes, endothelial cells, and the intestines, especially during hypoglycemia. Because glutamine is not thought to cross the blood-brain barrier significantly, the implications of low blood glutamine in these children are not recognized. Yet children with high brain glutamine from urea cycle disorders are rarely diagnosed with autistic disorders. Other common events in autistic children that release vasopressin are gastrointestinal inflammation, hypoglycemia, and stress. Signs of hyponatremia in these children are salt cravings reported online and anecdotally, deep yellow urine revealing concentration, and relief of autistic behavior by fluid/salt diets. Several interventions offer promise: (a) taurine to suppress vasopressin and replenish astrocytes; (b) glutamine as fuel for intestines and brain; (c) arginine to spare glutamine, detoxify ammonia, and increase brain blood flow; and (d) oral rehydration salts to compensate dilutional hyponatremia. This hypothesis appears eminently testable: Does your child crave salt? Is his urine deep yellow?

The significance of ammonia/gamma-aminobutyric acid (GABA) ratio for normality and liver disorders

Cohen has illustrated that extremely high Gamma-aminobutyric acid (GABA) levels in the urine and blood and high plasma ammonia were observed for an autistic male child diagnosed with infantile autism. GABA is a major inhibitory neurotransmitter of the mammalian brain and the enzyme responsible for catabolism is GABA-Transaminase (GABA-T). Elevated levels of ammonia in the plasma results in a decrease in the efficiency for the GABA-T enzyme and this results in higher GABA concentrations after regulation in the liver. It is postulated that a link between plasma ammonia and plasma GABA exists where the concentration of GABA in the plasma is directly related to the ammonia plasma concentration. A ratio of approximately 0.30 (plasma ammonia/GABA) is a consistent finding for normal subjects and for subjects with infantile autism and liver diseases such as hepatic encephalopathy.

Use of a GABA-transaminase agonist for treatment of infantile autism

This paper describes the use of a GABA-transaminase agonist for the treatment of infantile autism. An approximate one third reduction of GABA and ammonia levels for an autistic patient with noticeable improvement of verbal/language skills and a reduction of repetitious ritualistic self-stimulatory behavior (stimming) was observed. A reduction of the plasma GABA (by administrating a GABA-T agonist, Imipramine) probably results in more axon(s)-to-oligodendrocyte signaling in the corpus callosum and it is postulated that this could result in a reduction of the autistic features for the patient.

GABA-transaminase, the liver and infantile autism

Gamma-aminobutyric acid (GABA) is a major inhibitory neurotransmitter of the mammalian brain and the enzyme responsible for catabolism (breakdown in the liver during regulation) is GABA-Transaminase (GABA-T). Recently, Cohen has shown that extremely high GABA levels in the urine and blood were observed for an autistic child. The finding that elevated levels of GABA in the urine and blood are present for an autistic child could explain why autistic features (such as self-stimulatory behavior and language delays, etc.) are found. Increasing the GABA-T enzyme activity for this autistic patient could result in less plasma GABA (after liver regulation) entering into the bloodsteam and brain and it is postulated that this could result in a reduction of the autistic features (such as self-stimulatory behavior and language delays, etc.) due to abnormal development of the axon(s) in the corpus callosum.