GluD1 binds GABA and controls inhibitory plasticity

Activation of G protein-coupled estrogen receptor alleviates the abnormal changes of synaptic plasticity in the anterior insula of temporal lobe epilepsy rats through RhoA/Rock2 pathway

Temporal lobe epilepsy (TLE) is the most common type of refractory epilepsy, characterized by highly synchronized abnormal neuronal discharge. The insula cortex (IC) serves as a key "node" in the TLE transmission network, and the anterior insula (AI) is a critical gatekeeper to executive control; however, the pathological changes of the IC/AI have been overlooked. GPER1 is a G protein coupled estrogen receptor anchored by PSD95 to the plasma membrane of dendritic spine (DS), participating in the regulation of DS plasticity. We found that Gper1 deletion rats exhibited increased susceptibility to epilepsy, but it remains unclear whether and how GPER1 regulates alterations in DS plasticity in the IC after TLE induction. Here, we observed that the interaction between GPER1 and PSD95 diminished at TLE induction 7 d, the dendrite complexity and DS density were altered in the AI. While, activating of GPER1 ameliorated the neuronal damage and loss in the AI of TLE rats, decreased dendrite complexity and increased DS density，enhanced the interaction between GPER1 and PSD95, then mitigated the inhibition of Rock2 and its downstream targets, cofilin and the imbalance of F/G-actin, which was induced by the over-activation of CAMKII and RhoA. Thus, improved the emotion and cognitive dysfunction of TLE rats. Our results offer compelling evidence for elucidating the mechanism of abnormal changes in insular synaptic plasticity following TLE and the selection of therapeutic targets.

A-485 alleviates postmenopausal osteoporosis by activating GLUD1 deacetylation through the SENP1-Sirt3 signal pathway

OBJECTIVE

Postmenopausal osteoporosis (OP) is a bone disease caused by estrogen deficiency. A-485 is a selective inhibitor of p300/CBP histone acetyltransferase (HAT) with potential regulatory effects on bone remodeling. This study aims to investigate the effects of A-485 on postmenopausal OP and its underlying mechanisms.

METHODS

For animal experiments, 61 female Wistar rats were used to establish an OP model through ovariectomy (OVX). The rats were administered with A-485 (100 mg/kg/day) via intraperitoneal injection for six weeks. Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry (DXA). Histopathological changes were observed using HE and Masson's trichrome staining. ELISA was used to measure bone resorption markers (CTX-1, DPD) and the bone formation marker (P1NP) in rats. Osteoblast differentiation markers (Runx2, OCN), SENP1, Sirt3 expression levels, and GLUD1 acetylation were assessed via Western blot (WB) and RT-qPCR. In vitro, MC3T3-E1 osteogenic progenitor cells were cultured in osteogenic differentiation medium supplemented with ascorbic acid, β-glycerophosphate, dexamethasone, and fulvestrant. CCK-8 was performed to evaluate cell proliferation. Flow cytometry was selected to measure apoptosis and mitochondrial membrane potential. WB and RT-qPCR were employed to analyze ERα, ERβ, Runx2, Sirt3, and GLUD1 acetylation. Additionally, Alizarin red staining was applied to monitor osteoblast mineralization. ATP levels were detected using a commercial kit, and ROS levels were measured by MitoSOX Red.

RESULTS

In vivo, ovariectomized rats exhibited lower BMD, impaired bone trabeculae, increased CTX-1 and DPD, and altered expression of Runx2 and OCN, all of which were reversed by A-485 treatment. In vitro, A-485 activated GLUD1 deacetylation, enhanced osteogenic differentiation, and improved mitochondrial function. Regarding the mechanism, A-485 activated the SENP1-Sirt3 signal pathway, with SENP1 knockdown negating the effects of A-485. In vivo, A-485 reduced GLUD1 acetylation and promoted improvement of OP, which were reversed by SENP1 knockdown.

CONCLUSION

A-485 ameliorates postmenopausal OP by activating GLUD1 deacetylation via the SENP1-Sirt3 signal pathway, thus improving mitochondrial function, and promoting osteogenic differentiation and mineralization.

A Chemistry-Informed Generative Deep Learning Approach for Enhancing Voltammetric Neurochemical Sensing in Living Mouse Brain

Exploring the time-resolved dynamics of neurochemicals is essential for deciphering neuronal functions, intercellular communication, and neurophysiological or pathological mechanisms. However, the complex interplay among neurochemicals between neurocytes, coupled with extensive chemical signal crosstalk, puts simultaneous sensing of multiple neurochemicals into a longstanding challenge. Herein, we report a chemistry-informed generative neural network (CIGNN) model to separate the Faradaic and the non-Faradaic components from voltammetric currents, minimizing their mutual interference and enhancing quantitative accuracy. With the assistance of generative deep learning, we successfully establish a new platform for in vivo neurochemical sensing, which is validated by simultaneously monitoring the dynamics of dopamine (DA), ascorbic acid (AA), and ionic strength in a neuroinflammation mouse model. We observe that the stimulation with KCl solution triggers a significant enhancement of AA efflux on the model mice (300 ± 50 μM) compared with that from the control mice (170 ± 20 μM), as well as a significant decrease of ion influx (55 ± 7 mM) compared with that from the control mice (120 ± 16 mM), while not evoking a significant change in the DA release from the model mice (2.8 ± 0.3 μM) versus that from the control mice (3.0 ± 0.5 μM). This work provides a robust tool for studying multineurochemical signaling and elucidating the molecular mechanisms underlying various brain activities.

Molecular profiling reveals the malignant potential in solid pseudopapillary neoplasms of the pancreas

Solid pseudopapillary neoplasm of the pancreas (SPN) is a rare tumor primarily affecting middle-aged women, typically characterized by indolent behavior but occasionally demonstrating malignant potential through invasive growth and metastasis. To elucidate the molecular mechanisms driving this heterogeneity, a multi-omics approach was applied to analyze paired metastatic lesions, primary tumors, and normal pancreatic tissues. Methylation profiling via the Illumina Infinium Methylation EPIC BeadChip identified 2425 differentially methylated positions (DMPs) in metastatic versus primary lesions, with 798 DMPs conserved across both lesion types. Tyrosine kinases and cGMP-PKG signaling pathway were the most significantly enriched KEGG pathways involved in the DMPs. Transcriptomic analysis of invasive and non-invasive SPNs using NanoString revealed 99 differentially expressed genes (DEGs). Immunohistochemical validation confirmed elevated protein expression of LY96, IFI16, and GLUD1 in invasive cases. Circulating free DNA (cfDNA) sequencing did not detect genetic mutation in non-metastatic SPN, in contrast, 42.9 % positivity of genetic mutations were detected in metastatic SPNs. Tumor microenvironment analysis by using the GEO database, 850 K methylation sequencing, NanoString transcriptome, highlighted enriched immune-suppressive stromal components in aggressive tumors. These findings establish a molecular signature linking methylation dysregulation, transcriptomic alterations, liquid biopsy, and immune evasion to SPN progression, offering potential biomarkers for risk stratification and therapeutic targeting.

Role of Achyranthes aspera in neurodegenerative diseases: current evidence and future directions

Neurodegenerative diseases are caused by the progressive degeneration of neurons and/or their myelin sheaths, ultimately leading to cognitive and motor dysfunction. Due to their complex pathogenesis and the limited efficacy of therapeutic drugs, these diseases have attracted significant attention. Achyranthes aspera, belongs to family Amaranthaceae, has been extensively used in the traditional and folk medicines for the treatment of various ailments. Modern research has revealed that Achyranthes aspera possesses various pharmacological effects, including cardiocerebrovascular protection, immune regulation, antioxidation, and anti-aging. Furthermore, the neuroprotective effects of Achyranthes aspera have been confirmed by numerous scientific studies. This review focuses on the primary pharmacological effects and mechanisms of Achyranthes aspera in the prevention and treatment of neurodegenerative diseases, as well as their potential application prospects. This review aims to provide insights into the potential clinical applications and research directions of Achyranthes aspera in neurodegenerative diseases.

From Stress to Synapse: The Neuronal Atrophy Pathway to Mood Dysregulation

Mood disorders, including major depressive disorder and bipolar disorder, are among the most prevalent mental health conditions globally, yet their underlying mechanisms remain incompletely understood. This review critically examines the neuronal atrophy hypothesis, which posits that chronic stress and associated neurobiological changes lead to structural and functional deficits in critical brain regions, contributing to mood disorder pathogenesis. Key mechanisms explored include dysregulation of neurotrophic factors such as brain-derived neurotrophic factor (BDNF), elevated glucocorticoids from stress responses, neuroinflammation mediated by cytokines, and mitochondrial dysfunction disrupting neuronal energy metabolism. These processes collectively impair synaptic plasticity, exacerbate structural atrophy, and perpetuate mood dysregulation. Emerging evidence from neuroimaging, genetic, and epigenetic studies underscores the complexity of these interactions and highlights the role of environmental factors such as early-life stress and urbanization. Furthermore, therapeutic strategies targeting neuroplasticity, including novel pharmacological agents, lifestyle interventions, and anti-inflammatory treatments, are discussed as promising avenues for improving patient outcomes. Advancing our understanding of the neuronal atrophy hypothesis could lead to more effective, sustainable interventions for managing mood disorders and mitigating their global health burden.

The Chronobiological and Neuroprotective Mechanisms of Resveratrol in Improving Sleep

According to statistics, more than one-third of the global population currently experiences sleep problems, and about 10% of adults have been diagnosed with insomnia, a proportion that is increasing annually. Most currently used insomnia medications are not specifically developed but are discovered by chance, often resulting in unavoidable side effects like addiction. Thus, there is an urgent need to find safer and more effective therapeutic options. Resveratrol, a natural polyphenolic compound, shows significant potential in improving insomnia. Research shows that its effects may be achieved through multiple biological processes, including antiapoptosis, antioxidant activity, anti-inflammation, circadian rhythm regulation, modulation of neurotransmitters (gamma-aminobutyric acid (GABA), DA, 5-HT, cortisol), and increased levels of neurotrophic factor BDNF. Additionally, resveratrol's treatment of insomnia is closely linked to the SIRT1, AMPK, NF-κB, mTOR, PI3K/Akt, and MAPK pathways. This review summarizes the mechanisms of resveratrol in treating insomnia to provide researchers with a deeper understanding of its action, which can aid in the development of novel targeted drugs and offer innovative ideas and methods for clinical insomnia treatment.

Pleiotropic neurotransmitters: neurotransmitter-receptor crosstalk regulates excitation-inhibition balance in social brain functions and pathologies

Neuronal excitation-inhibition (E/I) balance is essential for maintaining neuronal stability and proper brain functioning. Disruptions in this balance are implicated in various neurological disorders, including autism spectrum disorder, schizophrenia and epilepsy. The E/I balance is thought to be primarily mediated by intrinsic excitability, governed by an array of voltage-gated ion channels, and extrinsic excitability, maintained through a counterbalance between excitatory synaptic transmission primarily mediated by excitatory transmitter glutamate acting on excitatory ion-tropic glutamate receptors and inhibitory synaptic transmissions chiefly mediated by GABA or glycine acting on their respective inhibitory ion-tropic receptors. However, recent studies reveal that neurotransmitters can exhibit interactions that extend beyond their traditional targets, leading to a phenomenon called neurotransmitter-receptor crosstalk. Examples of such crosstalks include earlier discovery of inhibitory glycine functioning as co-transmitter gating on the NMDA subtype of excitatory glutamate receptor, and the most recent demonstration that shows the excitatory glutamate transmitter binds to the inhibitory GABAA receptor, thereby allosterically potentiating its inhibitory function. These studies demonstrate structurally and physiologically important crosstalk between excitatory and inhibitory synaptic transmission, blurring the distinction between the concepts of classic excitatory and inhibitory synaptic transmission. In this article, evidence supporting the forms of excitatory and inhibitory crosstalks will be briefly summarized and their underlying mechanisms will be discussed. Furthermore, this review will discuss the implications of these crosstalks in maintaining the E/I balance, as well as their potential involvement in synaptic plasticity and cognition in the context of social conditions.

Optimizing esketamine administration for postoperative depression: a comprehensive study on laparoscopic bariatric surgery patients

BACKGROUND

Previous studies have reported conflicting findings regarding the efficacy of esketamine in managing postoperative depression. While the positive effects of subanesthetic doses esketamine have been observed in treatment-resistant depression, the response to this medication in patients experiencing depression following surgery has not been consistent. Building upon the known impact of anesthesia on brain function, we have formulated a hypothesis suggesting that the timing of esketamine administration in relation to anesthesia may significantly affect its efficacy in managing postoperative depression. The aim of this study was to investigate the effect of esketamine administered at different time points before and after anesthesia.

METHODS

Our randomized, double-blind, controlled study involved 120 patients undergoing laparoscopic bariatric surgery, randomly divided into three groups. Group Post- ESK received an intravenous injection of esketamine at a dose of 0.2 mg/kg after anesthesia induction. Group Pre- ESK received the same esketamine dosage 2 h prior to anesthesia induction. Group Placebo served as the control group and received a 0.9% saline solution after induction. The primary outcome measures of the study were depression scores as measured by Patient Health Questionnaire-9 (PHQ-9) and plasma brain-derived neurotrophic factor (BDNF) levels.

RESULTS

On the first postoperative day, the PHQ-9 scores, incidence and severity of postoperative depression in the Pre-ESK group were significantly lower than those in the Post-ESK and placebo groups (P < 0.05). Additionally, plasma BDNF levels in the Pre-ESK group were significantly higher than those in the Post-ESK and placebo groups (P < 0.05). Notably, there was a negative correlation between PHQ-9 scores and plasma BDNF levels.

CONCLUSIONS

Our study supports the potential for subanesthetic dose esketamine to alleviate postoperative depression symptoms following laparoscopic bariatric surgery, and anesthetic drugs have a significant effect on its efficacy. The use of subanesthetic dose esketamine after anesthesia does not improve postoperative depression symptoms in patients undergoing laparoscopic bariatric surgery, while the use of sub-anesthetic dose esketamine before anesthesia can improve postoperative depression symptoms.

D-Serine disrupts Cbln1 and GluD1 interaction and affects Cbln1-dependent synaptic effects and nocifensive responses in the central amygdala

Ionotropic glutamate receptors (iGluRs) mediate fast excitatory neurotransmission in the nervous system. In addition to NMDA receptor co-agonists, D-serine is a ligand for glutamate delta receptors (GluDs) and interacts with the ligand-binding domain with low affinity. However, D-serine binding does not lead to typical ion channel currents in GluD1 or GluD2 but may contribute to synaptic plasticity. In the developing brain, D-serine binding to GluD2 facilitates long-term depression at parallel fiber-Purkinje cell synapses. However, the influence of D-serine on GluD1's interaction with its amino terminal domain synaptogenic ligand Cbln1 and its subsequent impact on synaptic function and behavior remains unexplored. Here, we found that D-serine inhibited the interaction between Cbln1 and GluD1 in an in vitro cell-binding assay. This effect was concentration-dependent, with an IC50 value of ~ 300 µM. Furthermore, in ex vivo central amygdala (CeA) slices application of recombinant Cbln1 (rCbln1), consistent with its synaptogenic property, produced a robust increase in excitatory neurotransmission and GluD1 expression. This effect of rCbln1 was partially blocked by pre-treatment with D-serine. Finally, in behavioral experiments, we observed that the pro-nociceptive effect of intra-CeA injection of rCbln1 was inhibited by pre-treatment with D-serine. In addition, the antinociceptive effect of intra-CeA rCbln1 injection in an inflammatory pain model was blocked by D-serine. Overall, these results demonstrated that D-serine binding to GluD1 reduces its interaction with Cbln1, which may be relevant to synaptic plasticity and behavior.

Ultrastructural Localization of Glutamate Delta Receptor 1 in the Rodent and Primate Lateral Habenula

Glutamate delta receptor 1 (GluD1) is a unique synaptogenic molecule expressed at excitatory and inhibitory synapses. The lateral habenula (LHb), a subcortical structure that regulates negative reward prediction error and major monoaminergic systems, is enriched in GluD1. LHb dysfunction has been implicated in psychiatric disorders such as depression and schizophrenia, both of which are associated with GRID1, the gene that encodes GluD1. Thus, disruption in GluD1 synaptic signaling may contribute to LHb dysfunction and the pathophysiology of LHb-associated disorders. Despite its strong cellular expression, little is known about the subsynaptic and subcellular localization of GluD1 in LHb neurons. Given that GluD1 is involved in the development and/or regulation of glutamatergic and GABAergic synapses in various brain regions, a detailed map of GluD1 synaptic localization is essential to elucidate its role in the LHb. To address this issue, we used immunoelectron microscopy methods in rodents and monkeys. In both species, GluD1 immunoreactivity was primarily expressed in dendritic profiles, with lower expression in somata, spines, and glial elements. Pre- and post-embedding immunogold experiments revealed strong GluD1 expression in the core of symmetric GABAergic synapses. Albeit less frequent, GluD1 was also found at the edges (i.e., perisynaptic) of asymmetric, putative glutamatergic synapses. Through the combination of anterograde tracing with immunogold labeling in rats, we showed that axon terminals from the entopeduncular nucleus and the lateral hypothalamus express postsynaptic GluD1 immunolabeling in the LHb. Our findings suggest that GluD1 may play a critical role in modulating GABAergic transmission in the rodent and primate LHb.

Understanding GABAergic synapse diversity and its implications for GABAergic pharmacotherapy

Despite the substantial contribution of disruptions in GABAergic inhibitory neurotransmission to the etiology of psychiatric, neurodevelopmental, and neurodegenerative disorders, surprisingly few drugs targeting the GABAergic system are currently available, partly due to insufficient understanding of circuit-specific GABAergic synapse biology. In addition to GABA receptors, GABAergic synapses contain an elaborate organizational protein machinery that regulates the properties of synaptic transmission. Until recently, this machinery remained largely unexplored, but key methodological advances have now led to the identification of a wealth of new GABAergic organizer proteins. Notably, many of these proteins appear to function only at specific subsets of GABAergic synapses, creating a diversity of organizer complexes that may serve as circuit-specific targets for pharmacotherapies. The present review aims to summarize the methodological developments that underlie this newfound knowledge and provide a current overview of synapse-specific GABAergic organizer complexes, as well as outlining future avenues and challenges in translating this knowledge into clinical applications.

Metabolism-related proteins as biomarkers for predicting prognosis in polycystic ovary syndrome

OBJECTIVE

The study aimed to explore the role of metabolism-related proteins and their correlation with clinical data in predicting the prognosis of polycystic ovary syndrome (PCOS).

METHODS

This research involves a secondary analysis of proteomic data derived from endometrial samples collected from our study group, which includes 33 PCOS patients and 7 control subjects. A comprehensive identification and analysis of 4425 proteins were conducted to screened differentially expressed proteins (DEPs). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were subsequently performed on the DEPs. To identify independent prognostic metabolism-related proteins, univariate Cox regression and LASSO regression were applied. The expression levels of these proteins were then used to develop a prognostic model, with their predictive accuracy evaluated through receiver operating characteristic (ROC) curves, decision curve analysis (DCA), and calibration curves. Furthermore, we also investigate the correlation between clinical data and prognostic proteins.

RESULTS

The study identified 285 DEPs between the PCOS and control groups. GO enrichment analysis revealed significant involvement in metabolic processes, while KEGG pathway analysis highlighted pathways such as glycolysis/gluconeogenesis and glucagon signaling. Ten key metabolism-related proteins (ACSL5, ANPEP, CYB5R3, ENOPH1, GLS, GLUD1, LDHB, PLCD1, PYCR2, and PYCR3) were identified as significant predictors of PCOS prognosis. Patients were separated into high and low-risk groups according to the risk score. The ROC curves for predicting outcomes at 6, 28, and 37 weeks demonstrated excellent predictive performance, with AUC values of 0.98, 1.0, and 1.0, respectively. The nomogram constructed from these proteins provided a reliable tool for predicting pregnancy outcomes. DCA indicated a net benefit of the model across various risk thresholds, and the calibration curve confirmed the model's accuracy. Additionally, we also found BMI exhibited a significant negative correlation with the expression of GLS (r =-0.44, p = 0.01) and CHO showed a significant positive correlation with the expression of LDHB (r = 0.35, p = 0.04).

CONCLUSION

The identified metabolism-related proteins provide valuable insights into the prognosis of PCOS. The protein based prognostic model offers a robust and reliable tool for risk stratification and personalized management of PCOS patients.

Input specificity of NMDA-dependent GABAergic plasticity in the hippocampus

Sensory experiences and learning induce long-lasting changes in both excitatory and inhibitory synapses, thereby providing a crucial substrate for memory. However, the co-tuning of excitatory long-term potentiation (eLTP) or depression (eLTD) with the simultaneous changes at inhibitory synapses (iLTP/iLTD) remains unclear. Herein, we investigated the co-expression of NMDA-induced synaptic plasticity at excitatory and inhibitory synapses in hippocampal CA1 pyramidal cells (PCs) using a combination of electrophysiological, optogenetic, and pharmacological approaches. We found that inhibitory inputs from somatostatin (SST) and parvalbumin (PV)-positive interneurons onto CA1 PCs display input-specific long-term plastic changes following transient NMDA receptor activation. Notably, synapses from SST-positive interneurons consistently exhibited iLTP, irrespective of the direction of excitatory plasticity, whereas synapses from PV-positive interneurons predominantly showed iLTP concurrent with eLTP, rather than eLTD. As neuroplasticity is known to depend on the extracellular matrix, we tested the impact of metalloproteinases (MMP) inhibition. MMP3 blockade interfered with GABAergic plasticity for all inhibitory inputs, whereas MMP9 inhibition selectively blocked eLTP and iLTP in SST-CA1PC synapses co-occurring with eLTP but not eLTD. These findings demonstrate the dissociation of excitatory and inhibitory plasticity co-expression. We propose that these mechanisms of plasticity co-expression may be involved in maintaining excitation-inhibition balance and modulating neuronal integration modes.

Lack of evidence for direct ligand-gated ion channel activity of GluD receptors

Delta receptors (GluD1 and GluD2), members of the large ionotropic glutamate receptor (iGluR) family, play a central role in numerous neurodevelopmental and psychiatric disorders. The amino-terminal domain (ATD) of GluD orchestrates synapse formation and maturation processes through its interaction with the Cbln family of synaptic organizers and neurexin (Nrxn). The transsynaptic triad of Nrxn-Cbln-GluD also serves as a potent regulator of synaptic plasticity, at both excitatory and inhibitory synapses. Despite these recognized functions, there is still debate as to whether GluD functions as a "canonical" ion channel, similar to other iGluRs. A recent report proposes that the ATD of GluD2 imposes conformational constraints on channel activity; removal of this constraint by binding to Cbln1 and Nrxn, or removal of the ATD, reveals channel activity in GluD2 upon administration of glycine (Gly) and d-serine (d-Ser), two GluD ligands. We were able to reproduce currents when Gly or d-Ser was administered to clusters of heterologous human embryonic kidney 293 (HEK293) cells expressing Cbln1, GluD2 (or GluD1), and Nrxn. However, Gly or d-Ser, but also l-glutamate (l-Glu), evoked similar currents in naive (i.e., untransfected) HEK293 cells and in GluD2-null Purkinje neurons. Furthermore, no current was detected in isolated HEK293 cells expressing GluD2 lacking the ATD upon administration of Gly. Taken together, these results cast doubt on the previously proposed hypothesis that extracellular ligands directly gate wild-type GluD channels.

Loss of activation by GABA in vertebrate delta ionotropic glutamate receptors

Ionotropic glutamate receptors (iGluRs) mediate excitatory signals between cells by binding neurotransmitters and conducting cations across the cell membrane. In the mammalian brain, most of these signals are mediated by two types of iGluRs: AMPA and NMDA (i.e. iGluRs sensitive to 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid and N-methyl-D-aspartic acid, respectively). Delta-type iGluRs of mammals also form neurotransmitter-binding channels in the cell membrane, but in contrast, their channel is not activated by neurotransmitter binding, raising biophysical questions about iGluR activation and biological questions about the role of delta iGluRs. We therefore investigated the divergence of delta iGluRs from their iGluR cousins using molecular phylogenetics, electrophysiology, and site-directed mutagenesis. We find that delta iGluRs are found in numerous bilaterian animals (e.g., worms, starfish, and vertebrates) and are closely related to AMPA receptors, both genetically and functionally. Surprisingly, we observe that many iGluRs of the delta family are activated by the classical inhibitory neurotransmitter, γ-aminobutyric acid (GABA). Finally, we identify nine amino acid substitutions that likely gave rise to the inactivity of today's mammalian delta iGluRs, and these mutations abolish activity when engineered into active invertebrate delta iGluRs, partly by inducing receptor desensitization. These results offer biophysical insight into iGluR activity and point to a role for GABA in excitatory signaling in invertebrates.

An unexpected role for a glutamate receptor

γ-Aminobutyric acid acts on a glutamate receptor, evoking synaptic plasticity.