HOOCCH2CH2CH2NH2

HOOC-CH2-CH2-CH2-NH2 is the structural representation of gamma-aminobutyric acid (GABA), a four-carbon molecule with a carboxyl group on one end and an amino group on the other. Its IUPAC name is 4-aminobutanoic acid, and its molecular formula is C4H9NO2. In physiological conditions it exists mainly as a zwitterion, with a deprotonated carboxylate and a protonated amine, making it a polar compound that does not readily cross the blood–brain barrier in its neutral form.

Biological role and metabolism: GABA is the principal inhibitory neurotransmitter in the vertebrate central nervous system, where it dampens neuronal excitability and helps regulate muscle tone, anxiety, and various neural circuits. It is synthesized from glutamate by glutamate decarboxylase, a reaction that requires pyridoxal phosphate (vitamin B6). GABA is primarily degraded by GABA transaminase and succinate semialdehyde dehydrogenase, producing succinate that feeds into the tricarboxylic acid cycle.

Receptors and pharmacology: GABA exerts its effects through GABA receptors, including GABA-A (ligand-gated chloride channel) and GABA-B (G-protein-coupled) receptors, with GABA-C (now often referred to as GABA-A rho) as another receptor type. Pharmacological agents that enhance GABA signaling, such as benzodiazepines (GABA-A modulators) or baclofen (GABA-B agonist), are used clinically to treat conditions like epilepsy and spasticity. Exogenous GABA as a supplement has limited brain uptake, so its direct therapeutic efficacy is varying and context-dependent.

Applications: Beyond its role as a neurotransmitter, GABA and its derivatives serve as research tools and chemical intermediates in synthesis. The compound is also studied for its potential nutritional and neuroprotective effects, though evidence for clinical benefits as a supplement remains inconclusive.