Glycine receptors are ligand-gated chloride channels. Channel opening is triggered by extracellular glycine (PubMed:16672662, PubMed:17114051, PubMed:24801766). Channel opening is also triggered by taurine and beta-alanine (By similarity). Channel characteristics depend on the subunit composition; heteropentameric channels are activated by lower glycine levels and display faster desensitization (By similarity). Plays an important role in the down-regulation of neuronal excitability (PubMed:9145798). Contributes to the generation of inhibitory postsynaptic currents (PubMed:16672662, PubMed:17114051, PubMed:24801766). Channel activity is potentiated by ethanol. Potentiation of channel activity by intoxicating levels of ethanol contribute to the sedative effects of ethanol (PubMed:24801766). Inhibited by strychnine. Inhibited by picrotoxin (PubMed:16672662). Channel activity is enhanced by 5 uM Zn(2+) and inhibited by 100 uM Zn(2+) (PubMed:17114051). Homopentamer (in vitro). Interacts with GLRB to form heteropentameric channels; this is probably the predominant form in vivo. Heteropentamer composed of two GLRA1 and three GLRB. Heteropentamer composed of three GLRA1 and two GLRB. Both homopentamers and heteropentamers form functional ion channels, but their characteristics are subtly different. Detected in spinal cord neurons (PubMed:9145798, PubMed:17114051, PubMed:24801766). Detected in brain stem neurons (PubMed:16672662, PubMed:24801766). Detected at lower levels in hippocampus and cerebellum (PubMed:24801766). Detected in the inner plexiform layer of the retina (at protein level) (PubMed:12975813). The channel pore is formed by pentameric assembly of the second transmembrane domain from all five subunits. Channel opening is effected by an outward rotation of the transmembrane domains that increases the diameter of the pore. Defects in Glra1 are the cause of the spasmodic (spd) phenotype, a mouse mutant which resembles the human neurological disease, hyperekplexia (or startle disease (STHE)) (PubMed:7920629). Defects in Glra1 are the cause of the lethal oscillator (spd-ot) phenotype. Mutant mice display a fine motor tremor and muscle spasms that begin at 2 weeks of age and progressively worsen, resulting in death by 3 weeks of age (PubMed:7874121). Heterozygous mice show an increased acoustic startle response (PubMed:9145798). Neurons from homozygous oscillator mice have dramatically reduced amplitude and frequency of glycinergic inhibitory postsynaptic currents (PubMed:16672662). The oscillator phenotype is due to the complete absence of Glra1 protein (PubMed:9145798). The alpha subunit binds strychnine. Belongs to the ligand-gated ion channel (TC 1.A.9) family. Glycine receptor (TC 1.A.9.3) subfamily. GLRA1 sub-subfamily.