The role of GABA neurotransmitter in the human central nervous system, physiology, and pathophysiology

GABA is the main inhibitory neurotransmitter of the central nervous system (CNS) and one of the most abundant neurotransmitters in mammals is distributed in most areas of the brain and participates in 40% of the inhibitory synapses of adult vertebrates. It is produced in the CNS, through the decarboxylation of glutamic acid, catalyzed by glutamic acid decarboxylase (GAD). GABA exerts its inhibitory effect through two types of specific receptors, GABA A (ionotropic) and GABA B (metabotropic), which show different pharmacological, structural, and molecular differences. Even though GABA plays a key role in the physiology of the CNS modulating different processes, also is involved in some pathologies, furthermore, is a target for several therapeutics drugs. For instance, GABA has important involvement in sleep cycle regulation, and for decades benzodiaze-pines and gaboxadol have been prescribed for the treatment of insomnia. In epilepsy disease, the pharmacological and gene expression studies suggest a role in the prevention of seizures by blocking the regulation of GABA A receptors with specific antagonists. In depression and anxiety, studies indicate changes in the regulation of the genes which encoding GABA receptors. In the same way, GABA receptors have been associated with alcoholism and premenstrual syndrome. In conclusion, experimental evidence suggests, that the same subtype of GABA receptors showed a different pattern of cellular population and subcellular expression in different areas of the brain, modulating the excitability, and neuronal synchronization in different affection pathologies and conditions in humans.