GABA

γ-Aminobutyric acid (GABA) is the main inhibitory mediator in the central nervous system ((e.g. in the cerebellum, basal ganglia etc.) and is also found in the retina. It is formed by decarboxylation of glutamate, the reaction is catalyzed by the enzyme glutamate decarboxylase. It belongs to biogenic amines. The bond of GABA to GABA receptors (ionotropic GABAAand metabotropic GABAB) leads to hyperpolarization of the cellular wall. The GABA A receptor subclass serves as a binding site for benzodiazepines and barbiturates.