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GABA (gamma-aminobutyric acid)

Gamma-aminobutyric acid (GABA) is one of the major inhibitory transmitters in the central nervous system of mammals. Gamma aminobutyric acid (GABA) and glutamic acid are two major neurotransmitters involved in the regulation of brain neuronal activity. GABA is the major inhibitory neurotransmitter and L-glutamic acid is an excitatory transmitter. Gamma amino butyric acid (GABA) is the major inhibitory neurotransmitter in the insect CNS and periphery; modulating membrane potential through a GABA-gated chloride channel. GABA regulates neuronal excitability through binding to specific membrane proteins, which results in opening of an ion channel. The entry of chloride ion through the ion channel leads to hyperpolarization of the recipient cell, which consequently prevents transmission of nerve impulses to other cells. Low levels of GABA have been observed in individuals suffering from epileptic seizures, motion disorders, panic, anxiety, depression, alcoholism and manic behavior. GABA is not transported efficiently into the brain from the bloodstream because of poor transport properties that prevent passage through the blood-brain barrier. Consequently, brain cells synthesize virtually all of the GABA found in the brain (by decarboxylation of glutamic acid with pyridoxal phosphate). Because of the importance of GABA as an inhibitory neurotransmitter, and its effect on convulsive states and other motor dysfunctions, a variety of approaches have been taken to increase the brain GABA concentration. GABA analogs are known agents useful in antiseizure therapy for central nervous system disorders such as epilepsy, Huntington's chorea, cerebral ischemia, Parkinson's disease, tardive dyskinesia, and spasticity. It has also been suggested that the compounds can be used as antidepressants, anxiolytics and antipsychotics.

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