Gamma-Aminobutyric Acid

**Semantic type:** Pharmacologic Substance

**Definition:** A naturally occurring neurotransmitter with central nervous system (CNS) inhibitory activity. Gamma-aminobutyric acid (GABA), converted from the principal excitatory neurotransmitter glutamate in the brain, plays a role in regulating neuronal excitability by binding to its receptors, GABA-A and GABA-B, and thereby causing ion channel opening, hyperpolarization and eventually inhibition of neurotransmission.

**Synonyms:** - .GAMMA.-AMINOBUTYRIC ACID - 4-Aminobutanoic Acid - GABA - Piperidic Acid