Γ-aminobutyric Acid Levels Research Articles

Increased Serotonin Levels and Unchanged Glutamate and GABA Levels in Thalamic Microdialysates Despite Reduced Cell Numbers in a Valproic Acid-Induced Autism Model.

Autism spectrum disorders (ASDs) are increasingly prevalent neurodevelopmental disorders characterized by deficits in social skills, abnormal sensory responses and a loss of neuronal cells. A key factor in these differences is thought to be an imbalance between excitation and inhibition. The aim of this study was to measure the levels of γ-aminobutyric acid (GABA), glutamate (GLU) and serotonin (5-HT) in the thalamus of a rat valproic acid (VPA)-induced ASD model and to correlate these levels with the number of thalamic cells. Ten pregnant Wistar rats were injected with 600mg/kg VPA on Day 12.5 of gestation, whereas five control rats received saline. After the behavioral tests, the male pups were divided into ASD and control groups with ten animals each. At 55 days of age, pups underwent microdialysis under anesthesia, and thalamic samples were analyzed for GABA, GLU and 5-HT levels by ultrahigh-performance liquid chromatography (UHPLC). After microdialysis, the brain sections were stained, and the volumes of the thalamus and hemispheres were calculated using the Cavalieri method, with the number of neurons and glia determined using the optical fractionator method. Compared with the control group, the ASD group presented increased 5-HT levels, an increased hemispheric volume, a decreased thalamic volume and decreased numbers of thalamic neurons and glia. A negative correlation was observed between the GLU content and glial number in the control group but not in the ASD group. These results indicate a disturbed thalamic neurotransmitter balance. We suggest that the increased thalamic 5-HT levels in ASD rats indicates that 5-HT reuptake is inhibited by the GLU content, which remains unchanged, despite the reduced cell number.

Banxia Baizhu Tianma Decoction alleviates pentylenetetrazol-induced epileptic seizures in rats by preventing neuronal cell damage and apoptosis and altering serum and urine metabolic profiles

Ethnopharmacological relevanceEpilepsy (EP) is one of the most prevalent chronic neurological disorders in children, characterised by a prolonged course and a propensity for recurrence. Banxia Baizhu Tianma Decoction (BBTD), a traditional Chinese medicine formula, is commonly employed in the clinical management of EP and has demonstrated satisfactory therapeutic effects. Aim of the studyThis study aimed to evaluate the anti-epileptic effects of BBTD and to explore its molecular mechanisms. Materials and methodsEP rat model was induced by pentylenetetrazol (PTZ) and treated with BBTD. Parameters such as seizure grade and duration were recorded to evaluate the improvement of BBTD on epileptic behavior. Nissl staining was used to observe the pathological changes in the cerebral motor cortex. The expression levels of the Bax and Bcl-2 in the motor cortex were measured by western blot analysis to assess neuronal damage and apoptosis. The therapeutic action of BBTD was evaluated by examining the levels of neurotransmitters γ-aminobutyric acid (GABA) and glutamate (Glu) in the brain tissue of EP rats, along with assessments of neuronal damage and apoptosis. Non-targeted metabolomics techniques were employed to conduct a comprehensive analysis of serum and urine metabolites, and network analysis of metabolite-related targets was performed to enhance understanding of the anti-epileptic effects and mechanisms of BBTD. ResultsAfter BBTD treatment, the EP model rats exhibited reduced seizure severity and shortened seizure duration. Moreover, BBTD mitigated PTZ-induced neuronal damage, as evidenced by a significant increase in the number of Nissl bodies in the motor cortex following treatment. At the same time, BBTD inhibited neuronal apoptosis, as demonstrated by the up-regulation of the anti-apoptotic protein Bcl-2 and down-regulation of the pro-apoptotic protein Bax in the brain tissue of treated rats. In addition, BBTD reversed the decreased levels of GABA and the increased levels of Glu in the brain tissue of the model group. Metabolomics analyses suggested that BBTD treatment for EP may be closely associated with alterations in urinary metabolites related to vitamin B6 and pyrimidine metabolism, as well as serum metabolites involved in purine metabolism, glycerophospholipid metabolism and vitamin B6 metabolism. Finally, network analysis of metabolite targets indicated that dopamine and alpha-linolenic acid metabolites may play significant roles in the therapeutic effects of BBTD on EP. ConclusionBBTD demonstrated anti-epileptic effects in PTZ-induced seizure rats by regulating neurotransmitter balance, reducing neuronal damage and inhibiting apoptosis, suggesting its potential for the development of novel AEDs. This is the first time that UHPLC-MS-based urine and serum metabolomics have been used to elucidate the anti-epileptic mechanism of BBTD, providing insights into the underlying mechanisms of BBTD's action.

GABA and glutamate measurements in temporal cortex of autistic children.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder and presents with challenges in social communication. A hypothesized underlying contributing mechanism is the imbalance in excitation and inhibition (E/I), partly influenced by the levels of excitatory neurotransmitter glutamate (Glu) and inhibitory neurotransmitter γ-aminobutyric acid (GABA) in the brain. Although many have reported the levels of GABA and Glu in the brain, only a few reports address the temporal cortex and then only with a small sample of autistic children, and often only in one hemisphere. We used a macromolecular suppressed edited-magnetic resonance spectroscopy (MRS) sequence to study GABA and Glu (as potential key players influencing E/I) in a large sample of children with ASD in the right and left temporal cortices of children with (N = 56) and without (N = 30) ASD (7-18 years). As a group, children with ASD exhibited no differences in the left hemisphere (GABA and Glu Cohen's |d|: 0.24 and 0.03), but the right hemisphere showed higher GABA and lower Glu concentrations (GABA and Glu Cohen's |d|: 0.53 and 0.65) compared to neurotypicals. Furthermore, a negative association was found between the right hemisphere Glu levels of the ASD group and a clinical assessment tool (r = -0.361, p = 0.022), reflecting autism trait severity (social responsiveness scale). In conclusion, we highlight the chemical abnormalities in children with ASD through a cross-sectional measurement. Longitudinal studies are warranted to determine whether these chemical levels persist or resolve over development.

Rebalance the Inhibitory System in the Elderly Brain: Influence of Balance Learning on GABAergic Inhibition and Functional Connectivity.

Aging involves complex processes that impact the structure, function, and metabolism of the human brain. Declines in both structural and functional integrity along with reduced local inhibitory tone in the motor areas, as indicated by reduced γ-aminobutyric acid (GABA) levels, are often associated with compromised motor performance in elderly adults. Using multimodal neuroimaging techniques including magnetic resonance spectroscopy (MRS), diffusion magnetic resonance imaging (MRI), functional MRI as well as transcranial magnetic stimulation to assess short-interval intracortical inhibition (SICI), this study explores whether these age-related changes can be mitigated by motor learning. The investigation focused on the effects of long-term balance learning (3 months) on intracortical inhibition, metabolism, structural, and functional connectivity in the cortical sensorimotor network among an elderly cohort. We found that after 3 months of balance learning, subjects significantly improved balance performance, upregulated sensorimotor cortical GABA levels and ventral sensorimotor network functional connectivity (VSN-FC) compared to a passive control group. Furthermore, correlation analysis suggested a positive association between baseline VSN-FC and balance performance, between baseline VSN-FC and SICI, and between improvements in balance performance and upregulation in SICI in the training group, though these correlations did not survive the false discovery rate correction. These findings demonstrate that balance learning has the potential to counteract aging-related decline in functional connectivity and cortical inhibition on the "tonic" (MRS) and "functional" (SICI) level and shed new light on the close interplay between the GABAergic system, functional connectivity, and behavior.

GABA (gamma-aminobutyric acid) levels in dorsal anterior cingulate cortex are negatively associated with food motivation in a pediatric sample

Food motivation varies between individuals, affecting body weight and risk for eating disorders. Prior neuroimaging studies in youth and adults have revealed functional and structural alterations in the anterior cingulate cortex [ACC] in those with obesity and disordered eating but have not investigated their neurochemical underpinnings. In a sample of 37 children aged 4 to 13 years old, we used Magnetic Resonance Spectroscopy [MRS] to assess levels of γ-aminobutyric acid [GABA] – the major inhibitory neurotransmitter in the human brain – quantified relative to creatine in a 27-ml voxel including the dorsal ACC. We used the CEBQ to assess trait food motivation. In analyses adjusting for age, lower GABA+/Cr levels in the dorsal ACC were associated with higher trait enjoyment of food. Higher enjoyment of food scores were in turn associated with higher energy intake during an ad libitum test meal and during a postprandial task assessing intake in the absence of hunger, and higher body weight. Our results indicate a role for GABA function in the dorsal ACC in determining individual variation in food motivation in children.

Intervention effects of Naoxintong capsules on psychological and cardiac status in depressed rats after heart failure

Abstract Background Depression is a common clinical phenomenon in the patients with heart failure (HF). In traditional Chinese medicine (TCM), diseases in the brain and heart are thought to be correlated and interact. Naoxintong capsules (NXT) has been used for treating cardio-cerebrovascular diseases, while its therapeutic effect on depression after HF remains unclear. Objective The aim of the study is to evaluate the intervention effect of NXT on depression after HF. Methods Sprague-Dawley rats were assigned into the following 5 groups: sham, model, NXT (250, 1000 mg/kg), and valsartan (8 mg/kg). Coronary artery occlusion was performed to induce HF and subsequent depression in rats. The cardiac function was evaluated by echocardiography, hematoxylin-eosin staining, and Masson trichrome staining. The sucrose preference test and Morris water maze test were carried out to assess the depressive behaviors in rats. The ultrastructure of hippocampal CA1 neurons was observed and the levels of corticotropin-releasing hormone in the hypothalamus, brain-derived neurotrophic factor in the cortex, and adrenocorticotropic hormone (ACTH) in the plasma were determined by enzyme-linked immunosorbent assay. The levels of dopamine, 5-hydroxytryptamine, norepinephrine, and γ-aminobutyric acid in the hippocampus were measured by UPLC-QQQ-MS. Results NXT reduced myocardial injury and pathological changes in the cardiac tissue and increased the left ventricular ejection fraction, left ventricular fractional shortening, and cardiac output. NXT increased the sugar preference rate and number of crossings and shortened the escape latency. Furthermore, the NXT treatment restored the levels of corticotropin-releasing hormone, adrenocorticotropic hormone, brain-derived neurotrophic factor, dopamine, and γ-aminobutyric acid to the baseline values. Conclusions NXT not only demonstrates cardioprotective effect but also attenuates depression in the rats after HF. It may exert the antidepressant effect by inhibiting the hyperactivity of the hypothalamic-pituitary-adrenal axis and recovering the levels of neurotrophic factors and neurotransmitters.

Brain Magnetic Resonance Imaging Responses to Nonhypoxic Hypobaric Decompression

INTRODUCTION: The pathophysiological basis of neurological decompression sickness and the association between cerebral subcortical white matter (WM) change and nonhypoxic hypobaria remain poorly understood. Recent study of altitude decompression sickness risk evaluated acute WM responses to intensive hypobaric exposure using brain magnetic resonance imaging. METHODS: Six healthy men (20 to 50 yr) completed 6 h of hyperoxic hypobaria during three same-day altitude chamber decompressions to pressure altitudes ≥ 22,000 ft (6706 m). Research magnetic resonance imaging sequences, conducted on the days preceding and following decompression, evaluated subcortical WM integrity, cerebral blood flow, neuronal integrity (fractional anisotropy), and neurometabolite concentrations. RESULTS: No subcortical lesions were evident on diffusion weighted imaging and WM fractional anisotropy was unaffected. Mean WM blood flow was upregulated by 20% to over 25 mL · 100 g−1 · min−1. Gray matter flow was unchanged. There were no changes in gray matter or cerebellar neurometabolites. In parietal subcortical WM, levels of γ-aminobutyric acid (GABA) fell from (mean ± SD) 1.68 ± 0.2 to 1.35 ± 0.3 institutional units while glutathione (GSH) fell from 1.71 ± 0.4 to 1.25 ± 0.3 institutional units. Lactate increased postexposure in five subjects. CONCLUSIONS: Postexposure decrements in GABA and GSH imply WM insult with loss of neuroprotection and oxidative stress. An association between decrements in GABA and GSH support a common origin, while GSH decrements also correlate with WM blood flow responses. WM lactate increments are prone to error but suggest dysregulation of subcortical microvascular flow. WM neurometabolite and blood flow indices did not normalize by 24 h postexposure. Connolly D, Davagnanam I, Wylezinska-Arridge M, Mallon D, Wastling S, Lee VM. Brain magnetic resonance imaging responses to nonhypoxic hypobaric decompression. Aerosp Med Hum Perform. 2024; 95(10):733–740.

Anti-viral Effects of Pavetta indica Methanolic Extract and Acyclovir on Behavioral and Biochemical Parameters in Streptozotocin-induced Alzheimer's Disease in Rats.

Alzheimer's disease is a neurological dysfunction of the brain caused by neurodegeneration and oxidative stress. Some viruses, such as herpes viruses, HSV-1, and HSV-2, are causative agents of Alzheimer's disease and result in β-amyloid peptide and tau protein accumulation in the brain. Some antiviral drugs, such as valacyclovir, acyclovir, and foscarnet, reduce amyloid-beta and P-tau. Pavetta indica leaves are also reported for their antiviral properties. The current study aimed to find out the significance of using Pavetta indica methanolic extract and acyclovir against Alzheimer's disease induced by streptozotocin. Wistar rats received acyclovir and Pavetta indica methanolic extract orally at different dose ranges (50, 150, 450 mg/kg) and (125, 250, 500 mg/kg), respectively. The standard therapy, Rivastigmine (2 mg/kg), was given orally. Intracerebroventricular-streptozotocin produced significant alternations in behavioral assessments, including locomotor activity test, Morris water maze test, and elevated plus maze test. Moreover, intracerebroventricular-streptozotocin ameliorated the antioxidant defense activity by decreasing levels of catalase, superoxide dismutase, and reduced glutathione while enhancing the oxidative stress markers, including malondialdehyde, and total nitrite levels. Finally, the main findings showed that intracerebroventricular-streptozotocin significantly increased the inflammatory marker, tumor necrosis factor-α, and disturbed neurotransmitter mediators, including levels of acetylcholinesterase, glutamate, and γ-amino butyric acid. In a dose-dependent manner, acyclovir and Pavetta indica methanolic extract treatments abrogated the streptozotocin-induced behavioral and neurological abnormalities in rats. The potential therapeutic effects of PIME and acyclovir administration in intracerebroventricular-streptozotocin-treated rats may be attributed to its potential antiviral, antioxidant, and anti-inflammatory effects. The current study suggests that Pavetta indica methanolic extract and acyclovir are promising therapeutic targets against Alzheimer's disease.

Aphrodisiac activity of aqueous extract of Anthonotha macrophylla (P. Beauv) leaves in paroxetine-induced sexual dysfunction male Wistar rats

Ethno-pharmacological relevanceAnthonotha macrophylla, a plant with extensive ethnomedicinal uses, has various parts attributed to healing properties. The bark is claimed to be used to treat venereal diseases while the roots are used to treat intestinal discomfort. Gum extract from the bark provides pain relief, while the leaves are used for treating gonorrhoea, diarrhoea, and malaria. Additionally, the leaves are believed to enhance sexual behaviour. Although the age-long folkloric use of Anthonotha macrophylla leaf as aphrodisiac in female rats was substantiated with scientific evidence, the study did not account for the aphrodisiac activity in paroxetine-induced sexual dysfunction in male rat model. Aim of the studyThis study investigated the aphrodisiac activity of aqueous extract of Anthonotha macrophylla leaves (AEAML) in paroxetine-induced sexual dysfunction male rats (PISDMR). Materials and methodsForty-two male rats (144.86 ± 1.21 g) were assigned into six groups (A-F). Group A received distilled water only, while PISDMR in Groups B, C, D, E and F received distilled water, 7.14 mg/kg body weight of sildenafil citrate (reference drug), 25, 50 and 100 mg/kg body weight of AEAML once daily for 7 days. Data were analyzed using a one-way Analysis of Variance (ANOVA) and Tukey's post-hoc test at a 5% level of significance after the determination of male sexual behaviour parameters and associated biochemical indices. ResultsAEAML contained 8 mineral elements and 14 amino acids; potassium (368.24 mg/100g) and glycine (352.70 mg/100g) were the most abundant while cadmium (0.01 mg/100g) and histidine (0.70 mg/100g) were the least. Administration of paroxetine prolonged/increased (p < 0.05) the mount latency (ML), intromission latency (IL), ejaculation latency (EL), post-ejaculatory interval (PEI), and lowered/reduced (p < 0.05) the mount frequency (MF), intromission frequency (IF) and ejaculation frequency (EF). Paroxetine also decreased the weight of the caudal epididymis, seminal vesicle, ventral prostate, and testis, levels of dihydrotestosterone (DHT), testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH), dopamine, acetylcholine (ACH), nitric oxide (NO), cyclic guanosine monophosphate (cGMP) and increased the levels of serotonin, γ-aminobutyric acid (GABA), phosphodiesterase V (PDE V) and acetylcholinesterase (AChE) of the animals. In contrast, AEAML significantly (p < 0.05) lowered/reduced the paroxetine-induced related increases in the ML, IL, EL, PEI, and prolonged/increased (p < 0.05) the paroxetine-induced related decreases in the MF, IF and EF. The AEAML also reversed (p < 0.05) the paroxetine-induced related decreases in the weight of the caudal epididymis, seminal vesicle, ventral prostate, testis, levels of DHT, testosterone, LH, FSH, dopamine, ACH, NO, cGMP and the paroxetine-induced related increases in the levels of serotonin, GABA, PDE V and AChE. ConclusionAEAML contains aphrodisiac bioactive agents that can be explored as drug lead for MSD.

Activation of GABABR Attenuates Intestinal Inflammation by Reducing Oxidative Stress through Modulating the TLR4/MyD88/NLRP3 Pathway and Gut Microbiota Abundance.

Oxidative stress emerges as a prominent factor in the onset and progression of intestinal inflammation, primarily due to its critical role in damaging cells and tissues. GABAergic signaling is important in the occurrence and development of various intestinal disorders, yet its effect on oxidative stress remains unclear. We attempted to assess whether GABAergic signaling participated in the regulation of oxidative stress during enteritis. The results showed that lipopolysaccharide (LPS) significantly decreased γ-aminobutyric acid (GABA) levels in the ileal tissues of mice. Interestingly, the application of GABA significantly repressed the shedding of intestinal mucosal epithelial cells and inflammatory cell infiltration, inhibited the expressions of proinflammatory factors, including granulocyte colony-stimulating factor and granulocyte-macrophage colony stimulating factor, and enhanced the levels of anti-inflammatory cytokines interleukin (IL)-4 and IL-10, indicating that GABA could alleviate enteritis in mice. This observation was further supported by transcriptome sequencing, revealing a total of 271 differentially expressed genes, which exhibited a marked enrichment of inflammatory and immune-related pathways, alongside a prominent enhancement of GABA B receptor (GABABR) signaling following GABA administration. Effectively, Baclofen pretreatment alleviated intestinal mucosal damage in LPS-induced mice, suppressed proinflammatory cytokines IL-1β, IL-6, and tumor necrosis factor alpha expressions, and boosted total antioxidant capacity, superoxide dismutase (SOD), and glutathione (GSH) levels. Moreover, Baclofen notably enhanced the viability of LPS-stimulated IPEC-J2 cells, contracted the proinflammatory secretion factors, and reinforced SOD, GSH, and catalase levels, emphasizing the anti-inflammatory and antioxidant effects associated with GABABR activation. Mechanistically, Baclofen restrained the mRNA and protein levels of toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 3 (NLRP3), and inducible nitric oxide synthase, while elevating nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 in both mice and IPEC-J2 cells, indicating that activating GABABR strengthened antioxidant abilities by interrupting the TLR4/MyD88/NLRP3 pathway. Furthermore, 16S rDNA analysis demonstrated that Baclofen increased the relative abundance of probiotic, particularly Lactobacillus, renowned for its antioxidant properties, while reducing the relative richness of harmful bacteria, predominantly Enterobacteriaceae, suggesting that GABABR signaling may have contributed to reversing intestinal flora imbalances to relieve oxidative stress in LPS-induced mice. Our study identified previously unappreciated roles for GABABR signaling in constricting oxidative stress to attenuate enteritis, thus offering novel insights for the treatment of intestinal inflammation.

Dysregulation of parvalbumin expression and neurotransmitter imbalance in the auditory cortex of the BTBR mouse model of autism spectrum disorder.

Individuals diagnosed with autism spectrum disorder (ASD) frequently exhibit abnormalities in auditory perception, a phenomenon potentially attributed to alterations in the excitatory and inhibitory cells constituting cortical circuits. However, the exact genetic factors and cell types affected by ASD remain unclear. The present study investigated the balance of excitatory and inhibitory activity in the auditory cortex using BTBR T+ Itpr3tf/J (BTBR) mice, a well-established model for autism research. Our investigation unveiled a reduction in parvalbumin-positive (PV+) neurons within the AC of BTBR mice. Remarkably, in vivo magnetic resonance spectroscopy studies disclosed an elevation in glutamate (Glu) levels alongside a decrement in γ-aminobutyric acid (GABA) levels in this cortical region. Additionally, transcriptomic analysis of the mouse model facilitated the classification of several ASD-associated genes based on their cellular function and pathways. By comparing autism risk genes with RNA transcriptome sequencing data from the ASD mouse model, we identified the recurrent target gene Scn1a and performed validation. Intriguingly, we uncovered the specific expression of Scn1a in cortical inhibitory neurons. These findings hold significant value for understanding the underlying neural mechanisms of abnormal sensory perception in animal models of ASD.

Stiff Person Syndrome and GAD Antibody-Spectrum Disorders.

Antibodies against glutamic acid decarboxylase (GAD), originally associated with stiff person syndrome (SPS), define the GAD antibody-spectrum disorders that also include cerebellar ataxia, autoimmune epilepsy, limbic encephalitis, progressive encephalomyelitis with rigidity and myoclonus (PERM), and eye movement disorders, all of which are characterized by autoimmune neuronal excitability. This article elaborates on the diagnostic criteria for SPS and SPS spectrum disorders, highlights disease mimics and misdiagnoses, describes the electrophysiologic mechanisms and underlying autoimmunity of stiffness and spasms, and provides a step-by-step therapeutic scheme. Very-high serum GAD antibody titers are diagnostic for GAD antibody-spectrum disorders and also predict the presence of GAD antibodies in the CSF, increased intrathecal synthesis, and reduced CSF γ-aminobutyric acid (GABA) levels. Low serum GAD antibody titers or the absence of antibodies generates diagnostic challenges that require careful distinction in patients with a variety of painful spasms and stiffness, including functional neurologic disorders. Antibodies against glycine receptors, first found in patients with PERM, are seen in 13% to 15% of patients with SPS, whereas amphiphysin and gephyrin antibodies, seen in 5% of patients with SPS spectrum disorders, predict a paraneoplastic association. GAD-IgG from different SPS spectrum disorders recognizes the same dominant GAD intracellular epitope and, although the pathogenicity is unclear, is an excellent diagnostic marker. The biological basis of muscle stiffness and spasms is related to autoimmune neuronal hyperexcitability caused by impaired reciprocal γ-aminobutyric acid-mediated (GABA-ergic) inhibition, which explains the therapeutic response to GABA-enhancing agents and immunotherapies. It is essential to distinguish SPS spectrum disorders from disease mimics to avoid both overdiagnoses and misdiagnoses, considering that SPS is treatable if managed correctly from the outset to prevent disease progression. A step-by-step, combination therapy of GABA-enhancing medications along with immunotherapies ensures prolonged clinical benefits.

Striatal GABA levels correlate with risk sensitivity in monetary loss.

Decision-making under risk is a common challenge. It is known that risk-taking behavior varies between contexts of reward and punishment, yet the mechanisms underlying this asymmetry in risk sensitivity remain unclear. This study used a monetary task to investigate neurochemical mechanisms and brain dynamics underpinning risk sensitivity. Twenty-eight participants engaged in a task requiring selection of visual stimuli to maximize monetary gains and minimize monetary losses. We modeled participant trial-and-error processes using reinforcement learning. Participants with higher subjective utility parameters showed risk preference in the gain domain (r = -0.59) and risk avoidance in the loss domain (r = -0.77). Magnetic resonance spectroscopy (MRS) revealed that risk avoidance in the loss domain was associated with γ-aminobutyric acid (GABA) levels in the ventral striatum (r = -0.42), but not in the insula (r = -0.15). Using functional magnetic resonance imaging (fMRI), we tested whether risk-sensitive brain dynamics contribute to participant risky choices. Energy landscape analyses demonstrated that higher switching rates between brain states, including the striatum and insula, were correlated with risk avoidance in the loss domain (r = -0.59), a relationship not observed in the gain domain (r = -0.02). These findings from MRS and fMRI suggest that distinct mechanisms are involved in gain/loss decision making, mediated by subcortical neurometabolite levels and brain dynamic transitions.

SLC45A4 encodes a mitochondrial putrescine transporter that promotes GABA de novo synthesis.

Solute carriers (SLC) are membrane proteins that facilitate the transportation of ions and metabolites across either the plasma membrane or the membrane of intracellular organelles. With more than 450 human genes annotated as SLCs, many of them are still orphan transporters without known biochemical functions. We developed a metabolomic-transcriptomic association analysis, and we found that the expression of SLC45A4 has a strong positive correlation with the cellular level of γ-aminobutyric acid (GABA). Using mass spectrometry and the stable isotope tracing approach, we demonstrated that SLC45A4 promotes GABA de novo synthesis through the Arginine/Ornithine/Putrescine (AOP) pathway. SLC45A4 functions as a putrescine transporter localized to the mitochondrial membrane to facilitate GABA production. Taken together, our results revealed a new biochemical mechanism where SLC45A4 controls GABA production.

Stereoselective Bioconcentration and Neurotoxicity of Perfluoroethylcyclohexane Sulfonate in Marine Medaka.

Perfluoroethylcyclohexane sulfonate (PFECHS) is an emerging per- and polyfluoroalkyl substance used to replace perfluorooctane sulfonate (PFOS), mainly in aircraft hydraulic fluids. However, previous research indicates the potential neurotoxicity of this replacement chemical. In this study, marine medaka (Oryzias melastigma) was exposed to environmentally relevant concentrations of PFECHS (concentrations: 0, 0.08, 0.26, and 0.91 μg/L) from the embryonic stage for 90 days. After exposure, the brain and eyes of the medaka were collected to investigate the bioconcentration potential of PFECHS stereoisomers and their effects on the nervous systems. The determined bioconcentration factors (BCFs) of PFECHS ranged from 324 ± 97 to 435 ± 89 L/kg and from 454 ± 60 to 576 ± 86 L/kg in the brain and eyes of medaka, respectively. The BCFs of trans-PFECHS were higher than those of cis-PFECHS. PFECHS exposure significantly altered γ-aminobutyric acid (GABA) levels in the medaka brain and disrupted the GABAergic system, as revealed by proteomics, implying that PFECHS can disturb neural signal transduction like PFOS. PFECHS exposure resulted in significant alterations in multiple proteins associated with eye function in medaka. Abnormal locomotion was observed in PFECHS-exposed medaka larvae, which was rescued by adding exogenous GABA, suggesting the involvement of disrupted GABA signaling pathways in PFECHS neurotoxicity.

Effects of Different Pretreatments on the GABA Content of Germinated Brown Rice

Brown rice germination increases γ-aminobutyric acid (GABA) levels and enhances its antioxidant activity. In this study, Kaohsiung 145 brown rice was used as the raw material, and soaked in various solutions for 6 h before being processed with either high-pressure processing (HPP) or ultrasonic treatment to increase the GABA content. The GABA and antioxidant components of brown rice were analyzed after 42 h of germination and subsequent air-drying to obtain a moisture content of 14%. The results showed that non-germinated brown rice had GABA at 7.10 mg/100 g and treatment with various soaking solutions (0.1% CaCl2, 0.1% Glu, 0.2% CaCl2, and 0.2% Glu) increased GABA contents. Specifically, 0.1% CaCl2 and 0.1% Glu exhibited higher GABA content, at 42.51 and 44.64 mg/100 g. Furthermore, the GABA content increased synergistically when combined with HPP (100 MPa, 10 min) and ultrasonic (20 min) treatments after soaking. The results showed that the GABA contents in germinated rice were the greatest after ultrasonic treatment, followed by HPP treatment, and the least with only soaking treatment. The treatments with 0.1% CaCl2 and 0.2% Glu combined with ultrasonic processing for 20 min resulted in the highest GABA content at 102.38 and 110.88 mg/100 g, respectively. Finally, 0.1% CaCl2 with ultrasonic treatment for 20 min was chosen, as it demonstrated a considerable improvement in total polyphenols content and DPPH scavenging abilities, as seen by improved scores in subsequent taste evaluations.

Potential neuroprotective and autophagy-enhancing effects of alogliptin on lithium/pilocarpine-induced seizures in rats: Targeting the AMPK/SIRT1/Nrf2 axis

BackgroundStatus epilepticus (SE) as a severe neurodegenerative disease, greatly negatively affects people's health, and there is an urgent need for innovative treatments. The valuable neuroprotective effects of glucagon-like peptide-1 (GLP-1) in several neurodegenerative diseases have raised motivation to investigate the dipeptidyl peptidase-4 (DPP-4) inhibitor; alogliptin (ALO), an oral antidiabetic drug as a potential treatment for SE. ALO has shown promising neuroprotective effects in Alzheimer's and Parkinson's diseases, but its impact on SE has not yet been studied. AimThe present study aimed to explore the repurposing potential for ALO in a lithium/pilocarpine (Li/Pil)-induced SE model in rats. Main methodsALO (30 mg/kg/day) was administered via gavage for 14 days, and SE was subsequently induced in the rats using a single dose of Li/Pil (127/60 mg/kg), while levetiracetam was used as a standard antiepileptic drug. Key findingsThe results showed that ALO reduced seizure severity and associated hippocampal neurodegeneration. ALO also increased γ-aminobutyric acid (GABA) levels, diminished glutamate spikes, and corrected glial fibrillary acidic protein (GFAP) changes. At the molecular level, ALO increased GLP-1 levels and activated its downstream signaling pathway, AMP-activated protein kinase (AMPK)/sirtuin-1 (SIRT1). ALO also dampened the brain's pro-oxidant response, curbed neuroinflammation, and counteracted hippocampal apoptosis affording neuroprotection. In addition, it activated autophagy as indicated by Beclin1 elevation. SignificanceThis study suggested that the neuroprotective properties and autophagy-enhancing effects of ALO make it a promising treatment for SE and can potentially be used as a management approach for this condition.

Lactobacillus brevis M2-Fermented Whey Protein Hydrolysate Increases Slow-Wave Sleep via GABAA Receptors in Rodent Models.

In this study, we investigated the effects of whey protein hydrolysate (WPH) fermented with Lactobacillus brevis on sleep behavior and GABAergic mechanisms in rodent models. Fermentation converted the glutamate in WPH to high (3.15 ± 0.21 mg/mL) levels of γ-aminobutyric acid (GABA). Fermented WPH (WP-SF) enhanced sleep duration in mice by increasing GABA content in the brain. The increase in sleep duration induced by WP-SF resulted from an increase in delta wave activity during non-rapid eye movement sleep, and its sleep-promoting effect in a caffeine-induced insomnia model was characterized by an increase in delta waves. WP-SF increased GABAergic receptors at both mRNA and protein levels. Cotreatment with GABAA receptor antagonists abolished the sleep-promoting effects of WP-SF, indicating that WP-SF shares binding sites with antagonists on GABAA receptors. Collectively, WP-SF effectively increased sleep duration by enhancing delta wave activity through GABAergic activation; thus, it is suggested as a functional food-grade ingredient for promoting sleep.

Treadmill running on neuropathic pain: via modulation of neuroinflammation.

Neuropathic pain is a type of chronic pain caused by an injury or somatosensory nervous system disease. Drugs and exercise could effectively relieve neuropathic pain, but no treatment can completely stop neuropathic pain. The integration of exercise into neuropathic pain management has attracted considerable interest in recent years, and treadmill training is the most used among exercise therapies. Neuropathic pain can be effectively treated if its mechanism is clarified. In recent years, the association between neuroinflammation and neuropathic pain has been explored. Neuroinflammation can trigger proinflammatory cytokines, activate microglia, inhibit descending pain modulatory systems, and promote the overexpression of brain-derived neurotrophic factor, which lead to the generation of neuropathic pain and hypersensitivity. Treadmill exercise can alleviate neuropathic pain mainly by regulating neuroinflammation, including inhibiting the activity of pro-inflammatory factors and over activation of microglia in the dorsal horn, regulating the expression of mu opioid receptor expression in the rostral ventromedial medulla and levels of γ-aminobutyric acid to activate the descending pain modulatory system and the overexpression of brain-derived neurotrophic factor. This article reviews and summarizes research on the effect of treadmill exercise on neuropathic pain and its role in the regulation of neuroinflammation to explore its benefits for neuropathic pain treatment.

Dexamethasone alleviates etomidate-induced myoclonus by reversing the inhibition of excitatory amino acid transporters.

Etomidate can induce myoclonus with an incidence of 50 ~ 85% during anesthesia induction. Dexamethasone, as a long-acting synthetic glucocorticoid, has neuroprotective effects. However, the effects of dexamethasone on the etomidate-induced myoclonus remain uncertain. Adult male Sprague-Dawley rats were randomly assigned to receive etomidate (1.5 mg/kg) plus dexamethasone (4 mg/kg) (etomidate plus dexamethasone group) or etomidate (1.5 mg/kg) plus the same volume of normal saline (NS) (etomidate plus NS group). The mean behavioral scores, local field potentials and muscular tension were recorded to explore the effects of dexamethasone on etomidate-induced myoclonus. Liquid chromatography coupled with tandem mass spectrometric system (LC-MS/MS), quantitative real-time polymerase chain reaction (qRT-PCR), and western blotting were applied to analyze the levels of glutamate and γ-aminobutyric acid (GABA), the mRNA and protein expression of excitatory amino acid transporters (EAATs), and plasma corticosterone levels at different time points after anesthesia. Compared with the etomidate plus NS treatment, the etomidate plus dexamethasone treatment significantly decreased the mean behavioral score at 1, 3, 4, and 5 min after administration; the peak power spectral density (PSD) (p = 0.0197) in the analysis of ripple waves; and the glutamate level (p = 0.0139) in the neocortex. However, compared with etomidate plus NS, etomidate plus dexamethasone increased the expression of the neocortical proteins of EAAT1 (p = 0.0207) and EAAT2 (p = 0.0022) and aggravated the inhibition of corticosterone at 4 h (p = 0.0019), 5 h (p = 0.0041), and 6 h (p = 0.0009) after administration. Dexamethasone can attenuate the myoclonus, inhibit the glutamate accumulation, and reverse the suppression of EAATs in the neocortex induced by etomidate following myoclonus, while conversely aggravating etomidate-induced adrenal suppression.