The function of GABRB1 (gamma-aminobutyric acid type A receptor subunit beta1, ENSG00000163288) is as follows. Beta subunit of the heteropentameric ligand-gated chloride channel gated by gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the brain (PubMed:10449790, PubMed:16412217, PubMed:26950270). GABA-gated chloride channels, also named GABA(A) receptors (GABAAR), consist of five subunits arranged around a central pore and contain one or two GABA active binding sites located at the alpha and beta subunit interfaces, depending on subunit composition (By similarity). When activated by GABA, GABAARs selectively allow the flow of chloride anions across the cell membrane down their electrochemical gradient (PubMed:10449790, PubMed:16412217, PubMed:26950270). Chloride influx into the postsynaptic neuron following GABAAR opening decreases the neuron ability to generate a new action potential, thereby reducing nerve transmission (PubMed:16412217, PubMed:26950270). Beta-containing GABAARs can simultaneously bind GABA and histamine where histamine binds at the interface of two neighboring beta subunits, which may be involved in the regulation of sleep and wakefulness (By similarity). {ECO:0000250|UniProtKB:P15431, ECO:0000250|UniProtKB:P28472, ECO:0000269|PubMed:10449790, ECO:0000269|PubMed:16412217, ECO:0000269|PubMed:26950270}.