Glycine receptor

The glycine receptor, or GlyR, is the receptor for the amino acid neurotransmitter glycine. It is one of the most widely distributed inhibitory receptors in the central nervous system.

Activation and inactivation
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.

Arrangement of subunits
Strychnine-sensitive glycine receptors 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.

Pathology
A mutation in GLRA1 is responsible for some cases of stiff person syndrome.