GABA is made in brain cells from glutamate and works by blocking nerve impulses. Glutamate fires the nerve impulses and GABA does the opposite by telling the nerves not to fire. In the case of GABA deficiency, nerve cells fire too often and too easily.hat is where GABA comes in. Gamma-Amino Butyric acid (GABA) is an amino acid which acts as a neurotransmitter in the central nervous system.