Glycine Receptor (GlyR)

The glycine receptor (GlyR) is a pentameric ligand-gated ion channel that mediates fast inhibitory neurotransmission, primarily in the central nervous system. It is a member of the Cys-loop superfamily of ligand-gated ion channels and plays a crucial role in motor coordination, regulation of respiration rhythm, pain signaling, and other higher brain functions. GlyRs mediate fast inhibitory transmission by allowing chloride ions to flow into neurons upon activation by glycine, causing hyperpolarization and reducing neuronal excitability. Alterations or mutations in glycine receptor genes or their trafficking can lead to neurological disorders such as hyperekplexia and epilepsy.

Binding of agonists like glycine opens the chloride channel, leading to hyperpolarization of the neuron and reduced excitability. Antagonists like strychnine competitively block glycine binding, preventing channel opening. Allosteric modulators can enhance or inhibit channel activity.