Ligand-gated chloride channel which is a component of the heteropentameric receptor for GABA, the major inhibitory neurotransmitter in the brain (By similarity). Plays an important role in the formation of functional inhibitory GABAergic synapses in addition to mediating synaptic inhibition as a GABA-gated ion channel (By similarity). Functions also as histamine receptor and mediates cellular responses to histamine (By similarity). Allosterically activated by benzodiazepines (By similarity). Activated by pentobarbitol (By similarity). Inhibited by the antagonist bicuculline (By similarity). Inhibited by zinc ions (By similarity). Heteropentamer, formed by a combination of alpha, beta, gamma, delta and rho chains. The extracellular domain contributes to synaptic contact formation. This subunit carries the benzodiazepine binding site. Belongs to the ligand-gated ion channel (TC 1.A.9) family. Gamma-aminobutyric acid receptor (TC 1.A.9.5) subfamily. GABRG2 sub-subfamily.