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The glycine receptor, or GlyR, is the receptor for the amino acid neurotransmitter glycine. GlyR is an ionotropic receptor that produces its effects through chloride current. It is one of the most widely distributed inhibitory receptors in the central nervous system and has important roles in a variety of physiological processes, especially in mediating inhibitory neurotransmission in the spinal cord and brainstem. The receptor can be activated by a range of simple amino acids including glycine, β-alanine and taurine, and can be selectively blocked by the high-affinity competitive antagonist strychnine. Caffeine is a competitive antagonist of GlyR. Gephyrin has been shown to be necessary for GlyR clustering at inhibitory synapses.〔 GlyR is known to colocalize with the GABAA receptor on some hippocampal neurons. Nevertheless, some exceptions can occur in the central nervous system where the GlyR α1 subunit and gephyrin, its anchoring protein, are not found in dorsal root ganglion neurons despite the presence of GABAA receptors. ==Arrangement of subunits== Strychnine-sensitive GlyRs are members of a family of ligand-gated ion channels. Receptors of this family are arranged as five subunits surrounding a central pore, with each subunit composed of four α helical transmembrane segments. There are presently four known isoforms of the α-subunit (α1-4) of GlyR that are essential to bind ligands (, , , ) and a single β-subunit (). The adult form of the GlyR is the heteromeric α1β receptor, which is believed to have a stoichiometry (proportion) of three α1 subunits and two β subunits or four α1 subunits and one β subunit. The α-subunits are also able to form functional homo-pentameric receptors in heterologous expression systems in African clawed frog's oocytes or mammalian cell lines,〔 and the α1 homomeric receptor is essential for studies of channel pharmacokinetics and pharmacodynamics. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Glycine receptor」の詳細全文を読む スポンサード リンク
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