Gamma-aminobutyric acid (GABA) receptor voltage channel subunit (PubMed:8016117, PubMed:8389005, PubMed:7527461, PubMed:8882620, PubMed:12805302, PubMed:24823815). GABA, an inhibitory neurotransmitter, mediates neuronal inhibition by binding to the GABA receptor and opening an integral chloride channel (PubMed:8389005, PubMed:7527461, PubMed:12805302). Together with glutamate receptor GluClalpha, plays an important role in the visual response by regulating the activity of ON/OFF-selective neurons (PubMed:31535971, PubMed:32075756). Plays a role in promoting sleep and sleep latency by regulating the activity of peptidergic PDF neurons (PubMed:18223647, PubMed:19038223, PubMed:19230663). In large ventral lateral clock neurons, clustering is mediated by Nlg4 and protein levels undergo daily degradation in response to the circadian clock (PubMed:24068821, PubMed:29174887). In neurons in the mushroom bodies, has a role in odor memory acquisition where it inhibits appetitive and aversive olfactory learning, probably upstream of adenylyl cyclase rut and GTPase activating protein Nf1 (PubMed:18093529, PubMed:19193904). In male-specific GABAergic neurons, plays a role in inhibiting male aggressive behavior during courtship (PubMed:24241395). Gamma-aminobutyric acid (GABA) receptor voltage channel subunit. Activated by agonist muscimol (PubMed:8016117, PubMed:12805302, PubMed:8389005, PubMed:24823815). Insensitive to zinc, glycine, glutamate, and baclofen, loreclezole, to antagonist bicuculline, glycine-receptor antagonist strychnine, and nonselective GABA and glycine antagonist RU 5135 (PubMed:8016117, PubMed:8389005, PubMed:8882620, PubMed:12805302). Insensitive to flunitrazepam, pentobarbitone or pregnane steroids such as 5alpha-pregnan-3alpha-ol-20-one (PubMed:8016117, PubMed:8882620, PubMed:12805302). Inhibited by insecticides picrotoxin (PTX), cyclodiene dieldrin, TBPS and lindane (PubMed:8016117, PubMed:8389005, PubMed:7527461). Inhibited by ivermectin, fipronil and pyrafluprole (PubMed:24823815). Inhibited by insecticides picrotoxin (PTX). Forms oligomers (PubMed:8882620). Interacts with Nlg4; the interaction mediates Rdl clustering (PubMed:24068821). Interacts with Fbxl4; the interaction mediates Rdl degradation (PubMed:29174887). Localizes to large ventral lateral clock neurons axonal varicosities which are synaptic inputs to ventral lateral neuron dendrites. Expressed in different parts of the brain: the mushroom bodies (alpha, alpha', beta, beta', gamma lobes and peduncles), the neurons projecting to the columnar-type neuron LC9 optic glomerulus, in interneurons connecting the paired olfactory lobes, antennal lobes, PDF-expressing small and large ventral lateral neurons (LNvs) of the circadian clock and lobula columnar neuron 11 (LC11) (at protein level) (PubMed:18093529, PubMed:19038223, PubMed:32339168, PubMed:19230663, PubMed:24068821, PubMed:29174887, PubMed:32075756). Expressed in all major ON pathway medulla neurons (Mi1, Tm3, Mi4, and Mi9) and in OFF pathway neurons (Tm1, Tm2, Tm4, and Tm9) (PubMed:31535971). In large ventral lateral neurons (lLNvs), undergoes daily rhythmic degradation which is inversely correlated with the activity of lLNvs, which is involved in the circadian clock (PubMed:29174887). Degradation levels are increased in the early hours of the morning and mediated by the E3 ubiquitin ligase Fbxl4 (PubMed:29174887). Partially edited. In lobula columnar neurons 11 (LC11) results in a reduction of visual responses to the motion of small objects (PubMed:32075756). RNAi-mediated knockdown in neurons leads to dis-inhibition of male aggressive behavior (PubMed:24241395). RNAi-mediated knockdown in neurons in the alpha/beta mushroom bodies enhances learning (PubMed:18093529). RNAi-mediated knockdown in mushroom bodies enhances appetitive olfactory learning (PubMed:19193904). RNAi-mediated knockdown in PDF-expressing neurons results in decreased sleep but does not alter waking activity, circadian period, or rhythmicity under dark-dark conditions (PubMed:19230663). Simultaneous knockout of adenylate cyclase rut does not enhance the phenotype (PubMed:19193904). Simultaneous knockout of E3 ligase Fbxl4 results in significantly increased duration of daytime sleep and nighttime sleep as well as shortened sleep onset latency (PubMed:29174887). Resistance is thought to be due to insensitivity of the cyclodiene/picrotoxinin binding site on the GABA(A) receptor-chloride ionophore complex. Belongs to the ligand-gated ion channel (TC 1.A.9) family. Gamma-aminobutyric acid receptor (TC 1.A.9.5) subfamily. Truncated N-terminus. Truncated N-terminus.