GABAA Receptor Expression Research Articles

Effect of apigenin on seizure susceptibility, parvalbumin immunoreactivity, and GABAA receptor expression in the hippocampal neurons in mice.

Effect of apigenin on seizure susceptibility, parvalbumin immunoreactivity, and GABAA receptor expression in the hippocampal neurons in mice.

Effect of two novel GABAA receptor positive allosteric modulators on neuropathic and inflammatory pain in mice.

Effect of two novel GABAA receptor positive allosteric modulators on neuropathic and inflammatory pain in mice.

NPAS4 depletion in POMC neurons protects from obesity and alters the feeding-regulated transcriptome in male mice.

Immediate Early Genes (IEGs), such as Neuronal PAS domain protein 4 (Npas4), are induced as part of the response to environmental stimuli. In the arcuate nucleus (ARC), proopiomelanocortin (POMC) neurons are critical in detecting peripheral signals to regulate food intake. To date, Npas4 has not been studied in the context of regulating food intake and its sites of action in the ARC are unknown. We found that Npas4 was induced in POMC neurons by refeeding, oral glucose and HFD. In order to explore the role of NPAS4 in POMC neurons a conditional knockout approach was used. POMC-NPAS4 KO males showed significantly reduced body weight starting at 10 weeks of HFD, which was due to decreased food intake. Single cell RNA-seq on ARC cells demonstrated that POMC neurons of KO mice showed an enhanced refeeding-induced transcriptional response, dysregulated IEG expression in response to refeeding, and reduced expression of genes encoding GABA-A receptor subunits. Cell-to-cell communication analysis revealed that POMC neurons of KO mice lost inhibitory GABAergic signaling inputs and gained excitatory glutamatergic signaling inputs. Taken together, these results suggest that Npas4 tempers the activity of POMC neurons and loss of Npas4 causes impairments in nutrient intake sensing. Mechanistically, this results from reduced expression of inhibitory GABA-A receptors and an overall increase in the feeding-induced POMC neuron transcriptional response. In conclusion, we report a role for the transcription factor Npas4 in POMC neurons of the ARC and demonstrate its importance in controlling feeding behavior in states of overnutrition.

Brainstem Neuroadaptations in Rodent Models of Parkinson's Disease.

A classical theory of a key pathophysiological change in Parkinson's disease (PD) is that GABAergic neurons in the substantia nigra pars reticulata (SNr), an output structure of the basal ganglia, become hyperactive following the dopaminergic loss. Increased GABA release from the SNr neurons is thus likely to induce neuroadaptations in structures receiving a direct projection from the SNr, including the parabrachial nucleus (PBN), superior colliculus (SC), and periaqueductal gray (PAG). We have shown that the PBN indeed exhibits cellular and molecular changes in PD rat models. We thus expected the SC and the PAG to likewise show neuroplasticity. The objective of the present work was to evaluate the cellular and molecular plasticity in both the SC (lateral and medial) and the PAG in PD rats with a partial or total dopaminergic lesion. We used Golgi-Cox to measure the spine density and spine morphology and Western blot to analyze GABAA receptor expression in both PD rat models compared to sham animals. We found an increase in spine density (thin and stubby types) following total dopaminergic lesions in the SC and the PAG. Additionally, increased GABAA receptor expression was observed in the lateral SC in the total lesion group only. These results suggest compensatory mechanisms in PD that may delay disease onset and contribute to both motor and nonmotor symptoms. Further investigation should be performed to fully understand the functional impact of the plasticity revealed in this work.

Dysregulation of miR‑24‑3p and miR‑186‑5p and GABAA receptor expression in focal cortical dysplasia.

Spontaneous synaptic activity mediated by GABAA receptor is associated with epileptogenicity in focal cortical dysplasia (FCD). miRNAs are potentially involved in the regulation of GABAA receptor subunit expression and activity. This study aimed to determine the expression of miRNAs in FCD and correlate their expression level with mRNA levels of GABAA receptor subunits. Expression of GABAA receptor subunits (α1 and α4) and miRNAs (miR‑155‑5p, miR‑186‑5p, and miR‑24‑3p) were evaluated using real‑time PCR in resected brain samples from FCD patients. miRNA levels were also determined in the serum of FCD patients. Spontaneous GABAA receptor‑mediated synaptic activity was measured using patch clamp technique. Significant increase in α1 and α4 subunit expression and miR‑155‑5p levels, while decrease in miR‑24‑3p and miR‑186‑5p levels, was observed in the brain samples of FCD. In the serum of FCD patients, miR‑155‑5p levels were increased, whereas miR‑24‑3p and miR‑186‑5p levels remained unaltered. Increased α4 subunit expression in FCD might be due to reduced levels of miR‑24‑3p and miR‑186‑5p. In addition, reduced miR‑186‑5p levels might be responsible for increased expression of α1 subunit. We also observed an increase in the spontaneous GABAA receptor‑mediated synaptic transmission in FCD. In conclusion, dysregulation of miRNAs and GABAA receptor expression suggest that these miRNAs may contribute to altered GABAA receptor‑mediated synaptic activity in FCD.

Sleep-enhancing activity of fermented pea protein hydrolysate with enhanced GABA content by Lactobacillus brevis SYLB 0016 fermentation.

Sleep is essential for overall health and wellbeing. This study investigated the sleep-promoting effects of fermented pea protein hydrolysate (PPF) with increased gamma-aminobutyric acid (GABA) content produced by Lactobacillus brevis SYLB 0016. The effects of PPF on sleep duration and structure were assessed in pentobarbital-induced ICR mice and Sprague Dawley (SD) rats using electroencephalogram (EEG) analysis. Hydrolysis of pea protein with Alcalase, Protana Prime, and Protana UBoost increased the amino nitrogen content, degree of hydrolysis and glutamate content to 160.51 mmol L-1. Fermentation by Lactobacillus brevis SYLB 0016 increased the GABA content from 3.16 to 90.35 mmol L-1. PPF significantly increased sleep duration (56.3 min) compared to the normal control (30.6 min) in pentobarbital-induced sleep tests. Non-rapid eye movement (NREM) sleep time increased with a significant rise in δ-waves activity following administration of 150 mg kg-1 of PPF. In caffeine-induced insomnia, both low- and high-dose PPF significantly increased sleep duration. Three weeks of oral PPF administration elevated GABAA and GABAB receptor expression, with GABAA receptor protein levels showing a significant change. Co-administration of flumazenil with PPF reduced sleep time, indicating the involvement of the GABAA receptor benzodiazepine site in PPF's sleep-enhancing effects. In conclusion, PPF with enhanced GABA content improves NREM sleep by increasing δ waves activity. As a hypoallergenic compound, PPF holds potential as a supplement to ameliorate sleep disorders. © 2025 Society of Chemical Industry.

GABA mitigates mitochondrial apoptosis induced by high temperature stress in the Pacific oyster (Crassostrea gigas).

High temperature is a critical environmental factor leading to mass mortality in oyster aquaculture in China. Recent advancements highlight the physiological regulation function of γ-aminobutyric acid (GABA) in the adaptation of environmental stress. This study examined the physiological responses of the Pacific oyster (Crassostrea gigas) upon high temperature exposure, focusing on the histopathological changes in gill, the GABA concentration, the mRNA expression and activities of apoptosis-related genes. Following 24h of exposure to seawater at 28°C, notable histopathological changes, including cellular swelling and vacuolization, along with an increase in TUNEL-positive cells were observed in the oyster gill, compared to the control group maintained at 18°C. Moreover, there was a significant increase in CgCaspase-3 transcripts, Caspase-3 and Caspase-9 activities in the gills, glutamate decarboxylase CgGAD transcripts in the haemocytes, and GABA concentrations in the haemolymph supernatant. Intervention with GABA markedly ameliorated these responses, including reducing the mRNA expression levels of CgBax, CgBak, CgCaspase-3, and CgCaspase-9, as well as the activities of Caspase-3/9. Furthermore, after the treatment with GABAA and GABAB receptor antagonists, the activities and expression levels of Caspase-3 and Caspase-9 significantly up-regulated under hightemperature stress. GABA treatment also significantly diminished the increased Caspase-3 activity by mitochondrial pathway apoptosis inducers. High temperature induced mitochondrial pathway apoptosis via increased caspase activities. The transcripts of CgGAD in haemocytes and GABA concentration in hemolymph supernatant also increased after high-temperature stress. GABA countered these effects through the activation of GABAA and GABAB receptors, reducing both caspase activity and expression of apoptosis-related genes.

The Anticonvulsant and Antioxidant Effect of Rosa Moschata (J) Fruit Extract in Pentylenetetrazole induced Epileptic Mouse Model

Background: Rosa moschata (J) (RM (J)) is widely used as a traditional medicine in different ailments including central nervous system diseases, hepatic and gastrointestinal disease. The current study focused on the anticonvulsant effects and memory improvement property of RM (J) fruit extract by the modulation of oxidative stress markers and GABAA receptor in pentylenetetrazole (PTZ) induced mice epileptic model. Methods: The epileptic mice model was developed using pentylenetetrazole (35 mg/kg). The extract were used at doses of 50 mg/kg, 100 mg/kg and 150 mg/kg. The seizure was evaluated according to the Racine Scale. Cognitive functions were evaluated using the Y Maze and Morris Water Maze behavioral tests. The antioxidant effect of RM (J) extract was measured by assessing the level of lipid peroxidation (LPO), superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT). Additionally, the effect of RM (J) extract on the expression of GABAA receptors was evaluated using the qPCR. Results: RM (J) fruit extract exhibited a significant (P<0.5) dose-dependent improvement in memory compared to the mice treated with PTZ. Furthermore, the RM (J) extract significantly increased the levels of GSH and CAT and reduced LPO level compared to the PTZ group. The onset time of seizure was prolong while duration of seizure was significantly short in RM (J) extract treated group compared to PTZ group. Interestingly, there was a significant increase in the expression of GABAA receptors in the groups treated with the RM (J) extract, compared to the PTZ group. Conclusions: RM (J) extracts showed anticonvulsant effect and memory improvement potential due to the reduction of oxidative stress markers and enhanced in the expression of GABAA receptors.

Comparative analysis of adenosine 1 receptor expression and function in hippocampal and hypothalamic neurons

BackgroundAdenosine, an ATP degradation product, is a sleep pressure factor. The adenosine 1 receptor (A1R) reports sleep need. Histaminergic neurons (HN) of the tuberomamillary nucleus (TMN) fire exclusively during wakefulness and promote arousal. All of them express GABAA receptors and are inhibited by GABA. Does adenosine contribute to their silencing?Subjects and treatmentResponses to adenosine were studied in mouse brain slices and primary dissociated cultures. For HN identification single-cell (sc)RT-PCR, reporter protein and pharmacology were used. Hippocampal Dentate Gyrus granular layer cells (DGgc) were studied in parallel.MethodsFiring frequency was recorded in patch-clamp configuration or by microelectrode arrays. A1R-expression was studied by scRT-PCR and semiquantitative PCR.ResultsMost DGgc were inhibited through A1R, detected with scRT-PCR in 7 out of 10 PDZd2-positive DGgc; all HN were A1R negative. One HN out of 25 was inhibited by adenosine. The A1R mRNA level in the hippocampus was 6 times higher than in the caudal (posterior) hypothalamus. Response to adenosine was weaker in hypothalamic compared to hippocampal cultures.ConclusionsMost HN are not inhibited by adenosine.

Necrostatin-1 as a Potential Anticonvulsant: Insights from Zebrafish Larvae Model of PTZ-Induced Seizures.

Epilepsy is a common neurological disorder affecting around 70 million people worldwide. Despite significant research and advancements in pharmaceutical therapies, the exact mechanisms underlying epileptogenesis remain unclear. As a result, current antiepileptic drug treatments are ineffective for approximately 30% of patients, providing only symptomatic relief. The epileptic process is influenced by the signaling of tumor necrosis factor alpha (TNFα), which affects neuronal excitability. The TNFα/TNFR1 signaling pathway and the role of RIPK1 in initiating inflammatory cell death pathways are well studied in human disorders. Dysregulation of RIPK1 is linked to inflammation and neurodegenerative diseases. Necrostatin-1 (Nec-1) selectively inhibits RIPK1 in various pathological conditions. The current study aimed to investigate the anticonvulsant properties of Nec-1 (a selective RIPK1 inhibitor) in PTZ-induced seizures in zebrafish larvae. Before the onset of seizures, zebrafish were treated with Nec-1 (15µM) for 24h at 6days post-fertilization (dpf), followed by exposure to 15mM of PTZ for 30min. Behavioral assessments were conducted to observe changes in locomotor activity. Additionally, c-Fos expression was measuredas an indicator of neuronal activation and analyzed mRNA levels of the astrocyte activation marker (GFAP) along with various inflammatory cytokines. Western blot analysis was conducted to evaluate GABAA receptor expression. Pretreatment with Nec-1 restored normal behavior and reversed the expression of c-Fos in zebrafish larvae induced by PTZ. Additionally, Nec-1 reduced the elevated mRNA expression of inflammatory cytokines and significantly suppressed TNF/TNFR1 signaling, thereby inhibiting the enhanced internalization of GABAA receptors. Our findings indicate that Nec-1 reduced the severity of PTZ-induced seizures in zebrafish by regulating behavior changes, suppressing inflammatory mediators, and enhancing the expression of GABAA receptors, suggesting potential anticonvulsant properties.

The TMEM132B-GABAA receptor complex controls alcohol actions in the brain

The TMEM132B-GABAA receptor complex controls alcohol actions in the brain

Erratum to: Expression of GABA-A Receptors and Cation-Chloride Cotransporters in the Hippocampus of Krushinsky–Molodkina Audiogenic Rats during the Postnatal Development

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Depolarization of mouse DRG neurons by GABA does not translate into acute pain or hyperalgesia in healthy human volunteers.

The majority of somatosensory DRG neurons express GABAA receptors (GABAAR) and depolarise in response to its activation based on the high intracellular chloride concentration maintained by the Na-K-Cl cotransporter type 1 (NKCC1). The translation of this response to peripheral nerve terminals in people is so far unclear. We show here that GABA (EC50 = 16.67μM) acting via GABAAR produces an influx of extracellular calcium in approximately 20% (336/1720) of isolated mouse DRG neurons. In contrast, upon injection into forearm skin of healthy volunteers GABA (1mM, 100μl) did not induce any overt sensations nor a specific flare response and did not sensitize C-nociceptors to slow depolarizing electrical sinusoidal stimuli. Block of the inward chloride transporter NKCC1 by furosemide (1mg/100μl) did not reduce electrically evoked pain ratings nor did repetitive GABA stimulation in combination with an inhibited NKCC1 driven chloride replenishment by furosemide. Finally, we generated a sustained period of C-fiber firing by iontophoretically delivering codeine or histamine to induce tonic itch. Neither the intensity nor the duration of histamine or codeine itch was affected by prior injection of furosemide. We conclude that although GABA can evoke calcium transients in a proportion of isolated mouse DRG neurons, it does not induce or modify pain or itch ratings in healthy human skin even when chloride gradients are altered by inhibition of the sodium coupled NKCC1 transporter.

Early differential impact of MeCP2 mutations on functional networks in Rett syndrome patient-derived human cerebral organoids.

Human cerebral organoids derived from induced pluripotent stem cells can recapture early developmental processes and reveal changes involving neurodevelopmental disorders. Mutations in the X-linked methyl-CpG binding protein 2 (MECP2) gene are associated with Rett syndrome, and disease severity varies depending on the location and type of mutation. Here, we focused on neuronal activity in Rett syndrome patient-derived organoids, analyzing two types of MeCP2 mutations - a missense mutation (R306C) and a truncating mutation (V247X) - using calcium imaging with three-photon microscopy. Compared to isogenic controls, we found abnormal neuronal activity in Rett organoids and altered network function based on graph theoretic analyses, with V247X mutations impacting functional responses and connectivity more severely than R306C mutations. These changes paralleled EEG data obtained from patients with comparable mutations. Labeling DLX promoter-driven inhibitory neurons demonstrated differences in activity and functional connectivity of inhibitory and excitatory neurons in the two types of mutation. Transcriptomic analyses revealed HDAC2-associated impairment in R306C organoids and decreased GABAA receptor expression in excitatory neurons in V247X organoids. These findings demonstrate mutation-specific mechanisms of vulnerability in Rett syndrome and suggest targeted strategies for their treatment.

Sex differences in motor learning flexibility are accompanied by sex differences in mushroom spine pruning of the mouse primary motor cortex during adolescence.

Although males excel at motor tasks requiring strength, females exhibit greater motor learning flexibility. Cognitive flexibility is associated with low baseline mushroom spine densities achieved by pruning which can be triggered by α4βδ GABAA receptors (GABARs); defective synaptic pruning impairs this process. We investigated sex differences in adolescent pruning of mushroom spine pruning of layer 5 pyramidal cells of primary motor cortex (L5M1), a site essential for motor learning, using microscopic evaluation of Golgi stained sections. We assessed α4GABAR expression using immunohistochemical and electrophysiological techniques (whole cell patch clamp responses to 100 nM gaboxadol, selective for α4βδ GABARs). We then compared performance of groups with different post-pubertal mushroom spine densities on motor learning (constant speed) and learning flexibility (accelerating speed following constant speed) rotarod tasks. Mushroom spines in proximal L5M1 of female mice decreased >60% from PND35 (puberty onset) to PND56 (Pubertal: 2.23 ± 0.21 spines/10 μm; post-pubertal: 0.81 ± 0.14 spines/10 μm, P < 0.001); male mushroom spine density was unchanged. This was due to greater α4βδ GABAR expression in the female (P < 0.0001) because α4 -/- mice did not exhibit mushroom spine pruning. Although motor learning was similar for all groups, only female wild-type mice (low mushroom spine density) learned the accelerating rotarod task after the constant speed task (P = 0.006), a measure of motor learning flexibility. These results suggest that optimal motor learning flexibility of female mice is associated with low baseline levels of post-pubertal mushroom spine density in L5M1 compared to male and female α4 -/- mice.

Hsp47 promotes biogenesis of multi-subunit neuroreceptors in the endoplasmic reticulum.

Protein homeostasis (proteostasis) deficiency is an important contributing factor to neurological and metabolic diseases. However, how the proteostasis network orchestrates the folding and assembly of multi-subunit membrane proteins is poorly understood. Previous proteomics studies identified Hsp47 (Gene: SERPINH1), a heat shock protein in the endoplasmic reticulum lumen, as the most enriched interacting chaperone for gamma-aminobutyric acid type A (GABAA) receptors. Here, we show that Hsp47 enhances the functional surface expression of GABAA receptors in rat neurons and human HEK293T cells. Furthermore, molecular mechanism study demonstrates that Hsp47 acts after BiP (Gene: HSPA5) and preferentially binds the folded conformation of GABAA receptors without inducing the unfolded protein response in HEK293T cells. Therefore, Hsp47 promotes the subunit-subunit interaction, the receptor assembly process, and the anterograde trafficking of GABAA receptors. Overexpressing Hsp47 is sufficient to correct the surface expression and function of epilepsy-associated GABAA receptor variants in HEK293T cells. Hsp47 also promotes the surface trafficking of other Cys-loop receptors, including nicotinic acetylcholine receptors and serotonin type 3 receptors in HEK293T cells. Therefore, in addition to its known function as a collagen chaperone, this work establishes that Hsp47 plays a critical and general role in the maturation of multi-subunit Cys-loop neuroreceptors.

Sex differences in behavior, cognitive, and physiological recovery following methamphetamine administration

Intact executive functions are required for proper performance of cognitive tasks and relies on balance of excitatory and inhibitory (E/I) transmission in the medial prefrontal cortex (mPFC). Hypofrontality is a state of decreased activity in the mPFC and is seen in several neuropsychiatric conditions, including substance use disorders. People who chronically use methamphetamine (meth) develop hypofrontality and concurrent changes in cognitive processing across several domains. Despite the fact that there are sex difference in substance use disorders, few studies have considered sex as a biological variable regarding meth-mediated hypoactivity in mPFC and concurrent cognitive deficits. Hypofrontality along with changes in cognition are emulated in rodent models following repeated meth administration. Here, we used a meth sensitization regimen to study sex differences in a Temporal Order Memory (TOM) task following short (7 days) or prolonged (28 days) periods of abstinence. GABAergic transmission, GABAA receptor (GABAAR) and GABA Transporter (GAT) mRNA expression in the mPFC were evaluated with patch-clamp recordings and RT-qPCR, respectively. Both sexes sensitized to the locomotor activating effects of meth, with the effect persisting in females. After short abstinence, males and females had impaired TOM and increased GABAergic transmission. Female rats recovered from these changes after prolonged abstinence, whereas male rats showed enduring changes. In general, meth appears to elicit an overall decrease in GABAAR expression after short abstinence; whereas GABA transporters are decreased in meth female rats after prolonged abstinence. These results show sex differences in the long-term effects of repeated meth exposure and suggest that females have neuroprotective mechanisms that alleviate some of the meth-mediated cognitive deficits.

The P2X7 Hypothesis of Central Post-Stroke Pain.

The present study examined how P2X7 receptor knockout (KO) modulates central post-stroke pain (CPSP) induced by lesions of the ventrobasal complex (VBC) of the thalamus in behaviors, molecular levels, and electrical recording tests. Following the experimental procedure, the wild-type and P2X7 receptor KO mice were injected with 10 mU/0.2 μL type IV collagenase in the VBC of the thalamus to induce an animal model of stroke-like thalamic hemorrhage. Behavioral data showed that the CPSP group induced thermal and mechanical pain. The P2X7 receptor KO group showed reduced thermal and mechanical pain responses compared to the CPSP group. Molecular assessments revealed that the CPSP group had lower expression of NeuN and KCC2 and higher expression of GFAP, IBA1, and BDNF. The P2X7 KO group showed lower expression of GFAP, IBA1, and BDNF but nonsignificant differences in KCC2 expression than the CPSP group. The expression of NKCC1, GABAa receptor, and TrkB did not differ significantly between the control, CPSP, and P2X7 receptor KO groups. Muscimol, a GABAa agonist, application increased multiunit numbers for monitoring many neurons and [Cl-] outflux in the cytosol in the CPSP group, while P2X7 receptor KO reduced multiunit activity and increased [Cl-] influx compared to the CPSP group. P2X4 receptor expression was significantly decreased in the 100 kDa but not the 50 kDa site in the P2X7 receptor KO group. Altogether, the P2X7 hypothesis of CPSP was proposed, wherein P2X7 receptor KO altered the CPSP pain responses, numbers of astrocytes and microglia, CSD amplitude of the anterior cingulate cortex and the medial dorsal thalamus, BDNF expression, [Cl-] influx, and P2X4 expression in 100 kDa with P2X7 receptors. The present findings have implications for the clinical treatment of CPSP symptoms.

Expression of GABA-A Receptors and Cation-Chloride Cotransporters in the Hippocampus of Krushinsky–Molodkina Audiogenic Rats during the Postnatal Development

Expression of GABA-A Receptors and Cation-Chloride Cotransporters in the Hippocampus of Krushinsky–Molodkina Audiogenic Rats during the Postnatal Development

Local effect of allopregnanolone in rat ovarian steroidogenesis, follicular and corpora lutea development

Allopregnanolone (ALLO) is a known neurosteroid and a progesterone metabolite synthesized in the ovary, CNS, PNS, adrenals and placenta. Its role in the neuroendocrine control of ovarian physiology has been studied, but its in situ ovarian effects are still largely unknown. The aims of this work were to characterize the effects of intrabursal ALLO administration on different ovarian parameters, and the probable mechanism of action. ALLO administration increased serum progesterone concentration and ovarian 3β-HSD2 while decreasing 20α-HSD mRNA expression. ALLO increased the number of atretic follicles and the number of positive TUNEL granulosa and theca cells, while decreasing positive PCNA immunostaining. On the other hand, there was an increase in corpora lutea diameter and PCNA immunostaining, whereas the count of TUNEL-positive luteal cells decreased. Ovarian angiogenesis and the immunohistochemical expression of GABAA receptor increased after ALLO treatment. To evaluate if the ovarian GABAA receptor was involved in these effects, we conducted a functional experiment with a specific antagonist, bicuculline. The administration of bicuculline restored the number of atretic follicles and the diameter of corpora lutea to normal values. These results show the actions of ALLO on the ovarian physiology of the female rat during the follicular phase, some of them through the GABAA receptor. Intrabursal ALLO administration alters several processes of the ovarian morpho-physiology of the female rat, related to fertility and oocyte quality.