What is "gamma-aminobutyric acid"

n. (context biochemistry physiology English) An amino acid found in the nervous systems of vertebrates and acting as an inhibitory neurotransmitter. Abbreviated as '''GABA'''.

gamma-Aminobutyric acid (γ-Aminobutyric acid) (also called GABA for short) is the chief inhibitory neurotransmitter in the mammalian central nervous system. It plays the principal role in reducing neuronal excitability throughout the nervous system. In humans, GABA is also directly responsible for the regulation of muscle tone.

Although in chemical terms it is an amino acid, GABA is rarely referred to as such in the scientific or medical communities, because the term "amino acid," used without a qualifier, by convention refers to the alpha amino acids, which GABA is not, nor is it considered to be incorporated into proteins.