Effect of GABAa-receptors on neuronal discharge and ion activity in focal seizures.

Focal seizures are a type of epileptic event that has plagued the medical community for a long time, and the existing drug treatment is mainly based on the modulation of ${GABA}_a$-receptors to affect GABAergic signaling to achieve the therapeutic purpose. The majority of research currently focuses on the impact of ${GABA}_a$-receptors on neuronal firing, failing to analyze the molecular and ionic mechanisms involved. Specifically, the research on deeper-level mechanisms on how ${GABA}_a$-receptors affect neuronal firing by altering ion activity has not been addressed. This research aimed to study the effects of different ${GABA}_a$-receptor structures on ion activity in focal seizures model by adjusting parameters of the ${GABA}_a$-receptors: the rise time constant (${tau}_1$) and decay time constant (${tau}_2$). The research indicates that as the values of ${tau}_1$ and ${tau}_2$ of the ${GABA}_a$-receptor change, the ion concentration will vary based on the change of the ${GABA}_a$-receptor potential. To a certain extent, the duration of epileptic activity will also be affected to a certain extent. In conclusion, the alteration of ${GABA}_a$-receptor structure will affect the inhibitory effect of interneurons on pyramidal neurons, and different parameters of the ${GABA}_a$-receptor will directly impact the therapeutic effect.

Alfaxalone does not have long-term effects on goldfish pyramidal neuron action potential properties or GABAA receptor currents.

Anesthetics have varying physiological effects, but most notably alter ion channel kinetics. Alfaxalone is a rapid induction and washout neuroactive anesthetic, which potentiates γ-aminobutyric acid (GABA)-activated GABAA receptor (GABAA-R) currents. This study aims to identify any long-term effects of alfaxalone sedation on pyramidal neuron action potential and GABAA-R properties, to determine if its impact on neuronal function can be reversed in a sufficiently short timeframe to allow for same-day electrophysiological studies in goldfish brain. The goldfish (Carassius auratus) is an anoxia-tolerant vertebrate and is a useful model to study anoxia tolerance mechanisms. The results show that alfaxalone sedation did not significantly impact action potential properties. Additionally, the acute application of alfaxalone onto naive brain slices caused the potentiation of whole-cell GABAA-R current decay time and area under the curve. Following whole-animal sedation with alfaxalone, a 3-h wash of brain slices in alfaxalone-free saline, with saline exchanged every 30 min, was required to remove any potentiating impact of alfaxalone on GABAA-R whole-cell currents. These results demonstrate that alfaxalone is an effective anesthetic for same-day electrophysiological experiments with goldfish brain slices.

Effects of combined exposure to ethanol and delta-9-tetrahydrocannabinol during adolescence on synaptic plasticity in the prefrontal cortex of Long Evans rats.

Significant exposure to alcohol or cannabis during adolescence can induce lasting disruptions of neuronal signaling in brain regions that are later to mature, such as the medial prefrontal cortex (mPFC). Considerably less is known about the effects of alcohol and cannabis co-use, despite its common occurrence. Here, we used male and female Long-Evans rats to investigate the effects of early-life exposure to ethanol, delta-9-tetrahydrocannabinol (THC), or their combination on high frequency stimulation (HFS)-induced plasticity in the prelimbic region of the mPFC. Animals were injected daily from postnatal days 30-45 with vehicle or THC (escalating doses, 3-20 mg/kg) and allowed to drink vehicle (0.1% saccharin) or 10% ethanol immediately after each injection. In vitro brain slice electrophysiology was then used to record population responses of layer V neurons following HFS in layer II/III after 3-4 weeks of abstinence. We found that THC exposure reduced body weight gains observed in ad libitum fed rats, and reduced intake of saccharin and ethanol. Compared to controls, there was a significant reduction in HFS-induced long-term depression (LTD) in rats exposed to either drug alone, and an absence of LTD in rats exposed to the drug combination. Bath application of indiplon or AR-A014418, which enhance GABAA receptor function or inhibit glycogen synthase kinase 3ß (GSK3ß), respectively, suggested the effects of ethanol, THC or their combination were due in part to lasting adaptations in GABA and GSK3ß signaling. These results suggest the potential for long-lasting adaptations in mPFC output following co-exposure to alcohol and THC.

Targeting GABA receptors with chalcone derivative compounds, what is the evidence?

INTRODUCTION: In medicinal chemistry, privileged structures have been frequently exploited as a successful template for drug discovery. Common simple scaffolds like chalcone are present in a wide range of naturally occurring chemicals. Chalcone exhibits extensive biological activity and has drawn attention in this context due to its function in the GABA receptor. Epilepsy and GABA receptors are related. It is a chronic neurological condition that affects globally. AREAS COVERED: Numerous neurological disorders, including anxiety and epilepsy, have been related to GABA, the brain's most prevalent inhibitory neurotransmitter. We go through the role of GABA receptors in anxiety and epilepsy in this review. The structure-activity relationship of chalcone and its derivatives on the GABA receptor is covered in our final section. EXPERT OPINION: GABA is a potential therapeutic target for issues associated with the nervous system. We talk about the potential effects of chalcone as a treatment for epilepsy and anxiety on the GABA receptor. Therefore, thorough research is necessary in this regard; the value of in silico tools in developing and enhancing GABA agonists is significant.

Astrocytic NKCC1 inhibits seizures by buffering Cl- and antagonizing neuronal NKCC1 at GABAergic synapses.

OBJECTIVE: A pathological excitatory action of the major inhibitory neurotransmitter γ-aminobutyric acid (GABA) has been observed in epilepsy. Blocking the Cl- importer NKCC1 with bumetanide is expected to reduce the neuronal intracellular Cl- concentration ([Cl- ]i ) and thereby attenuate the excitatory GABA response. Accordingly, several clinical trials of bumetanide for epilepsy were conducted. Although NKCC1 is expressed in both neurons and glial cells, an involvement of glial NKCC1 in seizures has not yet been reported. Astrocytes maintain high [Cl- ]i with NKCC1, and this gradient promotes Cl- efflux via the astrocytic GABAA receptor (GABAA R). This Cl- efflux buffers the synaptic cleft Cl- concentration to maintain the postsynaptic Cl- gradient during intense firing of GABAergic neurons, thereby sustaining its inhibitory action during seizure. In this study, we investigated the function of astrocytic NKCC1 in modulating the postsynaptic action of GABA in acute seizure models. METHODS: We used the astrocyte-specific conditional NKCC1 knockout (AstroNKCC1KO) mice. The seizurelike events (SLEs) in CA1 pyramidal neurons were triggered by tetanic stimulation of stratum radiatum in acute hippocampus slices. The SLE underlying GABAA R-mediated depolarization was evaluated by applying the GABAA R antagonist bicuculline. The pilocarpine-induced seizure in vivo was monitored in adult mice by the Racine scale. The SLE duration and tetanus stimulation intensity threshold and seizure behavior in AstroNKCC1KO mice and wild-type (WT) mice were compared. RESULTS: The AstroNKCC1KO mice were prone to seizures with lower threshold and longer duration of SLEs and larger GABAA R-mediated depolarization underlying the SLEs, accompanied by higher Racine-scored seizures. Bumetanide reduced these indicators of seizure in AstroNKCC1KO mice (which still express neuronal NKCC1), but not in the WT, both in vitro and in vivo. SIGNIFICANCE: Astrocytic NKCC1 inhibits GABA-mediated excitatory action during seizures, whereas neuronal NKCC1 has the converse effect, suggesting opposing actions of bumetanide on these cells.

Pharmaco-EEG analysis of ligands varying in selectivity for α1 subunit-containing GABAA receptors during the active phase in rats.

RATIONALE: Benzodiazepines are known to evoke changes in cortical electrophysiological activity that can be correlated with action at distinct γ-aminobutyric acid type A (GABAA) receptor subtypes. OBJECTIVES: We used electroencephalography (EEG) paired with electromyography (EMG) to evaluate the role of α1 subunit-containing GABAA receptors (α1GABAARs) in benzodiazepine-induced sedation and changes in EEG band frequencies during the active phase of the light/dark cycle. METHODS: Male Sprague-Dawley rats (N = 4/drug) were surgically instrumented with EEG/EMG electrodes. The rats were injected i.p. with zolpidem, an α1GABAAR-preferring compound, or L-838,417, which has selective efficacy for α2/3/5 subunit-containing GABAARs (i.e., α1GABAAR-sparing compound), in comparison with the non-selective benzodiazepine, triazolam. RESULTS: All ligands evaluated induced changes in sleep-wake states during the active phase consistent with an increase in slow-wave sleep (SWS). The degree of SWS increase appeared to be related to the magnitude of delta power band changes induced by the ligands, with the strongest effects engendered by the α1GABAAR-preferring drug zolpidem and the weakest effects by the α1GABAAR-sparing compound, L-838,417. Consistent with other research, a selective increase in beta band power was observed with L-838,417, which may be associated with α2GABAAR-mediated anxiolysis. CONCLUSIONS: Overall, these findings support the establishment of pharmaco-EEG "signatures" for identifying subtype-selective GABAA modulators in vivo.

Changes in social, sexual, and hedonic behaviors in rats in response to stress and restoration by a negative allosteric modulator of α5-subunit containing GABA receptor.

Major depressive disorder (MDD) is a debilitating and costly human condition. Treatment for MDD relies heavily on the use of antidepressants that are slow to produce mood-related changes and are not effective in all patients, such as selective serotonin reuptake inhibitors (SSRIs). Several novel compounds, including negative allosteric modulators of GABA-A receptors containing the α5-subunit (GABA-NAMs), are under investigation for potential fast acting therapeutic use in MDD. Preclinical evidence that these compounds produce a rapid antidepressant-like response comes primarily from simple tests of escape behavior and preference for rewarding stimuli after chronic stress. To increase the ethological relevance of these compounds, we tested the hypothesis that the GABA-NAM, L-655,708, would produce an antidepressant-like response in more complex stress-sensitive social and sex behaviors, which are of relevance to the symptoms of human depression. In male rats subjected to chronic restraint stress, injection of L-655,708 increased reward in a sexual conditioned place preference task, increased male sexual activity with a receptive female, and re-established male social dominance hierarchies within 24 h. We also report increased sucrose preference in the social defeat stress (SDS) model of depression following GABA-NAM administration, demonstrating that its antidepressant-like actions are independent of the type of chronic stress administered. This work extends the impact of GABA-NAMs beyond traditional tests of anhedonia and further supports the development of alpha5 subunit-selective GABA-NAMs as a potential fast-acting therapeutic approach for treating human MDD.

Altered GABAA receptor function in women with endometriosis: a possible pain-related mechanism.

INTRODUCTION: The mechanism underlying endometriosis-related pain remains poorly understood. Previous studies have indicated that γ-aminobutyric acid (GABA) type A (GABAA ) receptors and GABAergic substances (eg endogenous neurosteroids) play important mechanistic roles in various pain conditions. Our primary objective was to compare GABAA receptor function between women with endometriosis and healthy controls by performing a challenge test with diazepam, a GABAA receptor agonist, using the saccadic eye velocity as the main outcome. The secondary objective was to investigate the relation between GABAA receptor function and serum levels of allopregnanolone, an endogenous positive modulator of the GABAA receptor, in the participating women. MATERIAL AND METHODS: 15 women with pelvic pain and laparoscopically confirmed endometriosis and 10 healthy, symptom-free, control women, aged 18-40 years, underwent the diazepam challenge test during the follicular phase of the menstrual cycle. Basal serum allopregnanolone levels were measured prior to diazepam injection. RESULTS: Compared with healthy controls, women with pelvic pain and confirmed endometriosis had a significantly smaller change in saccadic eye velocity after GABAA receptor stimulation with diazepam, indicating lower sensitivity to diazepam. The saccadic eye velocity response was not correlated with the serum allopregnanolone levels. CONCLUSIONS: Women with painful endometriosis show altered GABAA receptor function, depicted as a muted response to an exogenous GABAA receptor agonist.

aGABRacadabra: A surprising new role for GABAA receptors in cortical development.

In this issue of Neuron, Babij, Ferrer, and colleagues provide new evidence that ß3 subunit of GABAA receptors is critical for the maturation of functional networks in the neonatal somatosensory cortex.

Non-sedative cortical EEG signatures of allopregnanolone and functional comparators.

Neurosteroids that positively modulate GABAA receptors are among a growing list of rapidly acting antidepressants, including ketamine and psychedelics. To develop increasingly specific treatments with fewer side effects, we explored the possibility of EEG signatures in mice, which could serve as a cross-species screening tool. There are few studies of the impact of non-sedative doses of rapid antidepressants on EEG in either rodents or humans. Here we hypothesize that EEG features may separate a rapid antidepressant neurosteroid, allopregnanolone, from other GABAA positive modulators, pentobarbital and diazepam. Further, we compared the actions GABA modulators with those of ketamine, an NMDA antagonist and prototype rapid antidepressant. We examined EEG spectra during active exploration at two cortical locations and examined cross-regional and cross-frequency interactions. We found that at comparable doses, the effects of allopregnanolone, despite purported selectivity for certain GABAAR subtypes, was indistinguishable from pentobarbital during active waking exploration. The actions of diazepam had recognizable common features with allopregnanolone and pentobarbital but was also distinct, consistent with subunit selectivity of benzodiazepines. Finally, ketamine exhibited no distinguishing overlap with allopregnanolone in the parameters examined. Our results suggest that rapid antidepressants with different molecular substrates may remain separated at the level of large-scale ensemble activity, but the studies leave open the possibility of commonalities in more discrete circuits and/or in the context of a dysfunctional brain.

GABA facilitates spike propagation through branch points of sensory axons in the spinal cord.

Movement and posture depend on sensory feedback that is regulated by specialized GABAergic neurons (GAD2+) that form axo-axonic contacts onto myelinated proprioceptive sensory axons and are thought to be inhibitory. However, we report here that activating GAD2+ neurons directly with optogenetics or indirectly by cutaneous stimulation actually facilitates sensory feedback to motor neurons in rodents and humans. GABAA receptors located at or near nodes of Ranvier of sensory axons cause this facilitation by preventing spike propagation failure at the many axon branch points, which is otherwise common without GABA. In contrast, GABAA receptors are generally lacking from axon terminals and so cannot inhibit transmitter release onto motor neurons, unlike GABAB receptors that cause presynaptic inhibition. GABAergic innervation near nodes and branch points allows individual branches to function autonomously, with GAD2+ neurons regulating which branches conduct, adding a computational layer to the neuronal networks generating movement and likely generalizing to other central nervous system axons.

Consequences: Bench to home.

Seizure clusters (also referred to as acute repetitive seizures) consist of several seizures interspersed with brief interictal periods. Seizure clusters can break down γ-aminobutyric acidergic (GABAergic) inhibition of dentate granule cells, leading to hyperactivation. Functional changes to GABAA receptors, which play a vital neuroinhibitory role, can include altered GABAA receptor subunit trafficking and cellular localization, intracellular chloride accumulation, and dysregulation of proteins critical to chloride homeostasis. A reduction in neuroinhibition and potentiation of excitatory neurotransmission in CA1 pyramidal neurons represent pathological mechanisms that underlie seizure clusters. Benzodiazepines are well-established treatments for seizure clusters; however, there remain barriers to appropriate care. At the clinical level, there is variability in seizure cluster definitions, such as the number and/or type of seizures associated with a cluster as well as the interictal duration between seizures. This can lead to delays in diagnosis and timely treatment. There are gaps in understanding between clinicians, their patients, and caregivers regarding acute treatment for seizure clusters, such as the use of rescue medications and emergency services. This lack of consensus to define seizure clusters in addition to a lack of education for appropriate treatment can affect quality of life for patients and place a greater burden on patient families and caregivers. For patients with seizure clusters, the sense of unpredictability can lead to continuous traumatic stress, during which patients and families live with a heightened level of anxiety. Clinicians can affect patient quality of life and clinical outcomes through improved seizure cluster education and treatment, such as the development and implementation of a personalized seizure action plan as well as prescriptions for suitable rescue medications indicated for seizure clusters and instructions for their proper use. In all, the combination of targeted therapy along with patient education and support can improve quality of life.

The ethanol inhibition of basolateral amygdala neuron spiking is mediated by a γ-aminobutyric acid type A-mediated tonic current.

BACKGROUND: The basolateral nucleus of the amygdala (BLA) plays an important role in the development of fear and anxiety-related behaviors. The BLA receives inputs from all sensory stimuli. After processing those stimuli, BLA neurons signal neurons within the central amygdala and other brain regions, including the ventral and dorsal striatum and frontal cortex. Studies suggest that the BLA is involved in drug dependence and in the reinforcing actions of ethanol. For example, acute exposure to ethanol reduces anxiety, while withdrawal from chronic ethanol exposure alters BLA synaptic transmission, which increases anxiety, a common underlying cause of relapse. Exposure to and withdrawal from chronic alcohol also disrupts many brain areas that connect with the BLA. Despite these important findings, the acute actions of alcohol on the intrinsic excitability of BLA neurons have not been fully characterized. METHODS: Brain slices containing the BLA were prepared from adult C57BL/6J male mice. Whole-cell and sharp electrode electrophysiological recordings were performed to characterize the effects of acute ethanol on BLA neuronal and astrocyte function, respectively. RESULTS: Ethanol inhibited action potential (AP) firing of BLA neurons but had no effect on BLA astrocyte resting membrane potential. The ethanol-induced inhibition of firing was concentration-dependent (11 to 66 mM) and accompanied by a reduction in the input resistance and an increase in the rheobase of BLA neurons. The inhibitory effect of ethanol was suppressed by picrotoxin, which blocks both γ-aminobutyric acid type A (GABAA ) and glycine receptors, but not by the selective glycine receptor antagonist strychnine, which suggests an involvement of GABAA receptors. Ethanol did not affect spontaneous inhibitory postsynaptic currents suggesting that the inhibition of BLA neuronal excitability by ethanol was not due to an increase in GABAA -mediated synaptic transmission. However, acute ethanol enhanced the amplitude of the holding current of BLA neurons, an effect that was prevented by picrotoxin, which by itself reduced the holding current. CONCLUSIONS: These results suggest that BLA neurons express a GABA-mediated tonic current that is enhanced by acute ethanol, which leads to reduced excitability of BLA neurons.

Pregnane neurosteroids exert opposite effects on GABA and glycine-induced chloride current in isolated rat neurons.

The ability of endogenous neurosteroids (NSs) with pregnane skeleton modified at positions C-3 and C-5 to modulate the functional activity of inhibitory glycine receptors (GlyR) and ionotropic É£-aminobutyric acid receptors (GABAA R) was estimated. The glycine and GABA-induced chloride current (IGly and IGABA ) were measured in isolated pyramidal neurons of the rat hippocampus and in isolated rat cerebellar Purkinje cells, respectively. Our experiments demonstrated that pregnane NSs affected IGABA and IGly in a different manner. At low concentrations (up to 5 µM), tested pregnane NSs increased or did not change the peak amplitude of the IGABA , but reduced the IGly by decreasing the peak amplitude and/or accelerating desensitization. Namely, allopregnanolone (ALLO), epipregnanolone (EPI), pregnanolone (PA), pregnanolone sulfate (PAS) and 5ß-dihydroprogesterone (5ß-DHP) enhanced the IGABA in Purkinje cells. Dose-response curves plotted in the concentration range from 1 nM to 100 µM were smooth for EPI and 5ß-DHP, but bell-shaped for ALLO, PA and PAS. The peak amplitude of the IGly was reduced by PA, PAS, and 5α- and 5ß-DHP. In contrast, ALLO, ISO and EPI did not modulate it. Dose-response curves for the inhibition of the IGly peak amplitude were smooth for all active compounds. All NSs accelerated desensitization of the IGly . The dose-response relationship for this effect was smooth for ALLO, PA, PAS and 5ß-DHP, but it was U-shaped for EPI, 5α-DHP and ISO. These results, together with our previous results on NSs with androstane skeleton, offer comprehensive overview for understanding the mechanisms of effects of NSs on IGly and IGABA .

Electrophysiological study of the effects of side products of RuBi-GABA uncaging on GABAA receptors in cerebellar granule cells.

The study of the GABAA receptor itself and its pharmacology is of paramount importance for shedding light on the role of this receptor in the central nervous system. Caged compounds have emerged as powerful tools to support research in this field, as they allow to control, in space and time, the release of neurotransmitters enabling, for example, to map receptors' distribution and dynamics. Here we focus on γ-aminobutyric acid (GABA)-caged compounds, particularly on a commercial complex called RuBi-GABA, which has high efficiency of uncaging upon irradiation at visible wavelengths. We characterized, by electrophysiological measurements, the effects of RuBi-GABA on GABAA receptors of rat cerebellar granule cells in vitro. In particular, we evaluated the effects of side products obtained after RuBi-GABA photolysis. For this purpose, we developed a procedure to separate the "RuBi-cage" from GABA after uncaging RuBi-GABA with a laser source; then, we compared electrophysiological measurements acquired with and without administering the RuBi-cage in the perfusing bath. In conclusion, to investigate the role of the "cage" molecules both near and far from the cell soma, we compared experiments performed changing the distance of the uncaging point from the cell.

Physiological Role of ATPase for GABAA Receptor Resensitization.

γ-Aminobutyric acid type A receptors (GABAARs) mediate primarily inhibitory synaptic transmission in the central nervous system. Following fast-paced activation, which provides the selective flow of mainly chloride (Cl-) and less bicarbonate (HCO3-) ions via the pore, these receptors undergo desensitization that is paradoxically prevented by the process of their recovery, referred to as resensitization. To clarify the mechanism of resensitization, we used the cortical synaptoneurosomes from the rat brain and HEK 293FT cells. Here, we describe the effect of γ-phosphate analogues (γPAs) that mimic various states of ATP hydrolysis on GABAAR-mediated Cl- and HCO3- fluxes in response to the first and repeated application of the agonist. We found that depending on the presence of bicarbonate, opened and desensitized states of the wild or chimeric GABAARs had different sensitivities to γPAs. This study presents the evidence that recovery of neuronal Cl- and HCO3- concentrations after desensitization is accompanied by a change in the intracellular ATP concentration via ATPase performance. The transition between the desensitization and resensitization states was linked to changes in both conformation and phosphorylation. In addition, the chimeric ß3 isoform did not exhibit the desensitization of the GABAAR-mediated Cl- influx but only the resensitization. These observations lend a new physiological significance to the ß3 subunit in the manifestation of GABAAR resensitization.

Why won't it stop? The dynamics of benzodiazepine resistance in status epilepticus.

Status epilepticus is a life-threatening neurological emergency that affects both adults and children. Approximately 36% of episodes of status epilepticus do not respond to the current preferred first-line treatment, benzodiazepines. The proportion of episodes that are refractory to benzodiazepines is higher in low-income and middle-income countries (LMICs) than in high-income countries (HICs). Evidence suggests that longer episodes of status epilepticus alter brain physiology, thereby contributing to the emergence of benzodiazepine resistance. Such changes include alterations in GABAA receptor function and in the transmembrane gradient for chloride, both of which erode the ability of benzodiazepines to enhance inhibitory synaptic signalling. Often, current management guidelines for status epilepticus do not account for these duration-related changes in pathophysiology, which might differentially impact individuals in LMICs, where the average time taken to reach medical attention is longer than in HICs. In this Perspective article, we aim to combine clinical insights and the latest evidence from basic science to inspire a new, context-specific approach to efficiently managing status epilepticus.

Synaptic inhibition in the lateral habenula shapes reward anticipation.

The lateral habenula (LHb) supports learning processes enabling the prediction of upcoming rewards. While reward-related stimuli decrease the activity of LHb neurons, whether this anchors on synaptic inhibition to guide reward-driven behaviors remains poorly understood. Here, we combine in vivo two-photon calcium imaging with Pavlovian conditioning in mice and report that anticipatory licking emerges along with decreases in cue-evoked calcium signals in individual LHb neurons. In vivo multiunit recordings and pharmacology reveal that the cue-evoked reduction in LHb neuronal firing relies on GABAA-receptor activation. In parallel, we observe a postsynaptic potentiation of GABAA-receptor-mediated inhibition, but not excitation, onto LHb neurons together with the establishment of anticipatory licking. Finally, strengthening or weakening postsynaptic inhibition with optogenetics and GABAA-receptor manipulations enhances or reduces anticipatory licking, respectively. Hence, synaptic inhibition in the LHb shapes reward anticipation.

GABAA α subunit control of hyperactive behavior in developing zebrafish.

GABAA receptors mediate rapid responses to the neurotransmitter gamma-aminobutyric acid and are robust regulators of the brain and spinal cord neural networks that control locomotor behaviors, such as walking and swimming. In developing zebrafish, gross pharmacological blockade of these receptors causes hyperactive swimming, which is also a feature of many zebrafish epilepsy models. Although GABAA receptors are important to control locomotor behavior, the large number of subunits and homeostatic compensatory mechanisms have challenged efforts to determine subunit-selective roles. To address this issue, we mutated each of the 8 zebrafish GABAA α subunit genes individually and in pairs using a CRISPR-Cas9 somatic inactivation approach and, then, we examined the swimming behavior of the mutants at 2 developmental stages, 48 and 96 h postfertilization. We found that disrupting the expression of specific pairs of subunits resulted in different abnormalities in swimming behavior at 48 h postfertilization. Mutation of α4 and α5 selectively resulted in longer duration swimming episodes, mutations in α3 and α4 selectively caused excess, large-amplitude body flexions (C-bends), and mutation of α3 and α5 resulted in increases in both of these measures of hyperactivity. At 96 h postfertilization, hyperactive phenotypes were nearly absent, suggesting that homeostatic compensation was able to overcome the disruption of even multiple subunits. Taken together, our results identify subunit-selective roles for GABAA α3, α4, and α5 in regulating locomotion. Given that these subunits exhibit spatially restricted expression patterns, these results provide a foundation to identify neurons and GABAergic networks that control discrete aspects of locomotor behavior.