GABA A receptor

GABA A receptor is a type of GABA receptor, which is a class of receptors that respond to the neurotransmitter gamma-aminobutyric acid (GABA), the chief inhibitory compound in the mature vertebrate central nervous system. GABA A receptors are ligand-gated ion channels that are activated by GABA, the major inhibitory neurotransmitter in the brain.

Structure

GABA A receptors are pentameric transmembrane receptors which consist of five subunits arranged around a central pore. Each subunit comprises four transmembrane domains with both the N- and C-terminus located extracellularly. The receptor sits in the membrane of its neuron, usually localized at a synapse, postsynaptically.

Function

The function of the GABA A receptor is to conduct chloride ions across the neuronal cell membrane, resulting in an inhibitory effect on neurotransmission by diminishing the chance of a successful action potential occurring. The reversal potential of the GABA-mediated inhibitory postsynaptic potential (IPSP) in normal conditions is usually around -70 mV, contrasting the GABA-mediated postsynaptic current.

Pharmacology

GABA A receptors are the targets of several classes of drugs, including but not limited to the benzodiazepines, barbiturates, and alcohols. These drugs do not bind to the same receptor site as GABA, but cause allosteric modulation of the receptor.

Clinical significance

Alterations in function of the GABA A receptor have been linked to various forms of neurological disorders, including epilepsy, anxiety, insomnia, and alcohol dependence.

See also

• GABA B receptor
• GABA C receptor
• GABA receptor antagonist
• GABA receptor agonist