Study reveals vehicle for sensing amino acids

DAVIS, CALIF. - Researchers have identified the mechanism that allows animals to recognize the amino-acid content in foods. Neurophysiologist Dorothy Gietzen and colleagues at the University of California-Davis (UC-Davis) School of Veterinary Medicine say the discovery has implications for the betterment of human health, particularly in epileptics, some of whom are influenced by amino-acid deficiencies.

Uncharged transfer ribonucleic acid (tRNA) triggers the recognition of amino-acid deficient diets by affecting two genes. The signaling pathway tells the neurons in the brain in order to send a signal to the segment of the animal's brain telling it to search for other food that contains amino acids. An interruption in this process is likely what causes epilepsy in animals and people, the study reveals.

"This constitutes a basic, well-conserved mechanism in the brain of mammals that allows them to respond to nutritional stress and seek out food that will improve their chances for survival," Gietzen says in a prepared statement.

Of the 20 amino acids found in animals, eight of them are indispensable, or cannot be produced by or stored in the body, so they must be obtained through foods.

The research pinpoints the anterior piriform cortex as the part of the brain associated with neural excitability and where seizures originate.

The National Institutes of Health and the U.S. Department of Agriculture funded the study, which appeared in the March 18 issue of the journal Nature.