Progabide is an analog and prodrug of gamma-aminobutyric acid. It is commonly used in the treatment of epilepsy. It has agonistic activity for both the GABAA and GABAB receptors. Progabide has been investigated for many diseases besides epilepsy, including Parkinson's disease, schizophrenia, clinical depression and anxiety disorder with varying success. (en)
Progabide binds to both GABA<sub>A</sub> and GABA<sub>B</sub> receptors located on the terminals of primary afferent fibers. Binding to GABA<sub>A</sub> results in an increased affinity of the GABA receptor for the amino acid, an augmented flux of chloride ions across the terminal membrane, and an increase in the amount of presynaptic inhibition. Activation of the GABA<sub>B</sub> receptors retards the influx of calcium ions into the terminals, thereby reducing the evoked release of excitatory amino acids and possibly other transmitters. (en)