page_title: GABAA receptor
hierarchical_section_title: GABAA receptor
caption_attribution_description: English: Schematic structure of the GABAA receptorУкраїнська: Структура субодиниці ГАМКA-рецептора
context_page_description: The GABAA receptor is an ionotropic receptor and ligand-gated ion channel. Its endogenous ligand is γ-aminobutyric acid, the major inhibitory neurotransmitter in the central nervous system. Upon opening, the GABAA receptor is selectively permeable to chloride ions and, to a lesser extent, to bicarbonate ions. Depending on the membrane potential and the ionic concentration difference, this can result in ionic fluxes across the pore. For instance, under physiological conditions Cl⁻ will flow out of the cell if the membrane potential is higher than the equilibrium potential for chloride ions if the receptor is activated. This causes an inhibitory effect on neurotransmission by diminishing the chance of a successful action potential occurring at the postsynaptic cell. The reversal potential of the GABAA-mediated inhibitory postsynaptic potential in normal solution is −70 mV, contrasting the GABAB IPSP.
  The active site of the GABAA receptor is the binding site for GABA and several drugs such as muscimol, gaboxadol, and bicuculline. The protein also contains a number of different allosteric binding sites which modulate the activity of the receptor indirectly.
context_section_description: The GABAA receptor (GABAAR) is an ionotropic receptor and ligand-gated ion channel. Its endogenous ligand is γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system. Upon opening, the GABAA receptor is selectively permeable to chloride ions (Cl⁻) and, to a lesser extent, to bicarbonate ions (HCO⁻). Depending on the membrane potential and the ionic concentration difference, this can result in ionic fluxes across the pore. For instance, under physiological conditions Cl⁻ will flow out of the cell if the membrane potential is higher than the equilibrium potential (also known as the reversal potential) for chloride ions if the receptor is activated. This causes an inhibitory effect on neurotransmission by diminishing the chance of a successful action potential occurring at the postsynaptic cell. The reversal potential of the GABAA-mediated inhibitory postsynaptic potential (IPSP) in normal solution is −70 mV, contrasting the GABAB IPSP (-100 mV).
  The active site of the GABAA receptor is the binding site for GABA and several drugs such as muscimol, gaboxadol, and bicuculline. The protein also contains a number of different allosteric binding sites which modulate the activity of the receptor indirectly. These allosteric sites are the targets of various other drugs, including the benzodiazepines, nonbenzodiazepines, neuroactive steroids, barbiturates, alcohol (ethanol), inhaled anaesthetics, and picrotoxin, among others.
  GABAA receptors occur in all organisms that have a nervous system. To a limited extent the receptors can be found in non-neuronal tissues. Due to their wide distribution within the nervous system of mammals they play a role in virtually all brain functions.
caption: Schematic structure of the GABAA receptor. Left: GABAA monomeric subunit embedded in a lipid bilayer (yellow lines connected to blue spheres). The four transmembrane α-helices (1–4) are depicted as cylinders. The disulfide bond in the N-terminal extracellular domain which is characteristic of the family of cys-loop receptors (which includes the GABAA receptor) is depicted as a yellow line. Right: Five subunits symmetrically arranged about the central chloride anion conduction pore. The extracellular loops are not depicted for the sake of clarity.
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