BUY (G)-Aminobutyric acid

(G)-aminobutyric acid (GABA) is an amino acid derivate, synthesized from glutamate by the pyridoxal-L-phosphate (PLP)-dependent enzyme, glutamate decarboxylase (GAD). GABA provides the primary inhibitory signaling in the adult mammalian brain (CNS), and, to some degree of controversy, exerts a depolarizing response in the developing brain. GABA is an agonist of two main receptor classes in the CNS: GABA_A, an ionic ligand gated channel, and GABA_B, a metabotrophic, G-protein coupled receptor. GABA_A is assembled by 5 out of 16 possible subunits with (A), (B) and either a (G) or a (D) (2:2:1 stoichiometry) being the most common. With an EC₅₀ between 3 - 12micro M it interacts with GABA to allow either an influx or an efflux of Cl- ions, into and out of the cell, respectively. GABA_B is a heterodimer comprised of the subunits GABA_B1 and GABA_B2. It reduces neurotransmitter release by inhibiting Ca^{2+/sup> channels when activated presynaptically, and facilitates inward rectifying potassium channels, postsynaptically. GABA deficiency is often the prime cause for epilepsy, with other notably disorders being autism, spasticity, anxiety disorders, schizophrenia, and stiff-person syndrome.}