Neurochemical Research最新文献

Epilepsy affects over 65 million individuals worldwide, with approximately 30% of patients resistant to conventional antiepileptic drugs (AEDs). Neuroinflammation and oxidative stress are recognized contributors to epileptogenesis and seizure severity. Ammi visnaga (toothpick plant), traditionally used for its anti-inflammatory and antioxidant properties, remains understudied in the context of seizure-related neuroinflammation. This study aimed to investigate the neuroprotective, anticonvulsant, anti-inflammatory, and antioxidant properties of Ammi visnaga fruit hydroalcoholic extract in a pentylenetetrazole (PTZ)-induced seizure model in mice, with a particular focus on hippocampal oxidative stress and cytokine modulation. Forty adult male NMRI mice were randomized into Six groups including: both healthy negative control and PTZ + saline control, PTZ-only, phenobarbital-treated, and Ammi visnaga-treated (25, 50, and 100 mg/kg). Seizure latency, hippocampal expression of IL-6 and TNF-α (via qPCR) and oxidative stress biomarkers (MDA, nitrite, TAC) were assessed. Seizure latency significantly increased with Ammi visnaga treatment in a dose-dependent manner (P < 0.0001), with the 100 mg/kg group showing a robust delay compared to the PTZ group. Cytokine mRNA expression (IL-6 and TNF-α, measured by qPCR) were markedly downregulated in all extract-treated groups, reaching levels comparable to healthy controls (P < 0.001). Oxidative stress markers showed clear modulation; MDA and nitrite levels were significantly reduced in the hippocampus and serum at 100 mg/kg (P < 0.01 and P < 0.05, respectively). Total antioxidant capacity (TAC) was substantially enhanced in both serum and hippocampal tissue, particularly in the 50 and 100 mg/kg groups (P < 0.0001). In contrast, phenobarbital elevated seizure threshold but had minimal impact on oxidative stress biomarkers. Ammi visnaga fruit hydroalcoholic extract demonstrated potent, dose-dependent neuroprotective effects in a PTZ-induced seizure model through dual anti-inflammatory and antioxidative mechanisms. Its ability to suppress IL-6 and TNF-α expression and restore redox balance positions it as a promising adjunctive therapeutic candidate for epilepsy management, especially in drug-resistant cases driven by neuroinflammation and oxidative stress.

Tramadol, a widely used opioid analgesic, has been linked to neuropsychiatric side effects, including anxiety, when used chronically. These effects are believed to arise from disruptions in multiple neurotransmitter systems, including GABA, glutamate, dopamine, and serotonin. Valproic Acid (VAL), known for its mood-stabilizing and neuroprotective properties, may have the potential to counteract these effects. This study aimed to investigate the behavioral and neurochemical changes induced by chronic tramadol administration in rats and to evaluate the therapeutic potential of VAL in reversing these effects. Twenty-four male Sprague Dawley rats were divided into four groups: Control, Tramadol (TRA), Valproic Acid (VAL), and Tramadol + Valproic Acid (TRA + VAL). Behavioral assessments were conducted using the Open Field Test (OFT) and Light/Dark Box (LDT). After testing, levels of GABA, glutamate, dopamine, serotonin, acetylcholine, and norepinephrine were measured in the hypothalamus and cerebral cortex using LC-MS/MS. Chronic tramadol treatment led to anxiety-like behaviors, as seen in reduced center time in the OFT and shorter latency to enter dark areas in the LDT. These behavioral disruptions were accompanied by decreased levels of GABA in the hypothalamus and cerebral cortex. Co-treatment with VAL restored GABA levels and normalized behavior. The levels of most other neurotransmitters were also affected by tramadol, but not normalized by valproate. VAL mitigates tramadol-induced neurobehavioral disturbances by restoring key neurotransmitter imbalances in GABA. These findings support the therapeutic potential of VAL in managing opioid-induced mood and behavioral disruptions in opioid use disorder.

In the current study, we investigated the effects of 3-carene administration on basal brain activity and 4-aminopyridine (4-AP) induced epileptiform activity. Additionally, we examined the effects of asprosin on ECoG band powers. Thirty-five male Wistar rats were divided into five groups as follows: control (DMSO), 4-AP (2.5 mg/kg i.p.), 3-carene 10 mg/kg (i.p), 3-carene 50 mg/kg (i.p), 3-carene 50 mg/kg (i.p) post-treatment. Recordings lasting 60–70 min were conducted for all groups under ketamine/xylazine (90/10 mg/kg) anesthesia. Furthermore, we used thick acute horizontal hippocampal slices obtained from 30‑ to 35‑day‑old rats for in vitro experiments. Extracellular field potential recordings were evaluated in the CA1 region of the hippocampus. In vivo recordings revealed that intraperitoneal administration of 3-carene (10 mg/kg and 50 mg/kg) significantly suppressed basal brain activity across delta, theta, alpha, and beta bands. However, 3-carene failed to reduce epileptiform discharges induced by 4-AP. Complementary in vitro experiments using hippocampal and entorhinal cortex slices further confirmed the lack of anticonvulsant effect, as 3-carene did not alter the frequency or duration of 4-AP-induced ictal or interictal events. These findings suggest that while 3-carene modulates resting-state cortical oscillations, it lacks efficacy in suppressing seizure-like activity. The results highlight its potential as a neuromodulatory agent rather than a standalone anticonvulsant.

Previous research revealed a reduction in the VGF immunoreactivity within the substantia nigra (SN) of rats with a 60–90% dopaminergic neuron loss and in the plasma of newly diagnosed Parkinson’s disease (PD) patients. Hence, our aim was to explore whether central and peripheral proVGF changes occur during early dopaminergic dysfunction. To investigate this, we employed a rat model mimicking early-stage PD by injecting the SN unilaterally with an adeno-associated virus (AAV) carrying either the human α-synuclein (α-syn; n = 19) or green fluorescent protein (GFP; n = 18) gene. After conducting motor assessments and sacrificing the animals, brain and blood samples were collected. Tyrosine hydroxylase (TH)-, glutamic acid decarboxylase (GAD)-, and phosphorylated (p)-α-syn antibodies were used for immunohistochemistry (IHC), while an antibody targeting the C-terminus of proVGF was employed for IHC, western blot (WB), and enzyme linked immunosorbent asssay (ELISA). The α-syn overexpression caused a modest (~ 30%) reduction in TH immunoreactivity within the SN—without affecting the striatum—and did so without producing overt motor symptoms, effectively modeling a pre-symptomatic PD stage. This early dopaminergic dysfunction was accompanied by decreased immunostaining for both proVGF C-trerminus and GAD in the SN, but not the striatum. Reduction in plasma proVGF levels were also observed, indicating systemic changes during initial dopaminergic impairment. Analysis using WB confirmed a decrease in a 70 kDa band consistent with proVGF in both SN and plasma. These findings suggest proVGF as a promising early biomarker for PD, opening new avenues for intervention before the onset of clinical symptoms.

Changes in hippocampal neurons are known to play a critical role in social memory deficits associated with autism spectrum disorders (ASD). Although the theory of excitatory-inhibitory imbalance in autism pathogenesis is well established, early developmental alterations in the hippocampus remain insufficiently characterized. Alterations in gamma-aminobutyric acid (GABA)ergic neurons and their markers are thought to underlie synaptic changes in inhibitory circuits. Therefore, this study was designed to: (1) quantify glutamatergic and GABAergic neuron populations in the hippocampus; (2) characterize inhibitory postsynaptic currents (IPSCs) in primary hippocampal neurons; and (3) assess gene expression of selected GABAergic markers in two autism-like animal models, namely Shank3-deficient mice and prenatally valproate (VPA)-exposed rats. A reduced proportion of GABAergic neurons was observed in the hippocampus of both models. An increase in the number of glutamatergic neurons was found only in the hippocampus of prenatally VPA-exposed rats. This was accompanied by a decrease in IPSC frequency in primary hippocampal neurons from prenatally VPA-exposed rats, while no significant changes were found in Shank3-deficient mice. Altered temporal dynamics of inhibitory synaptic transmission were demonstrated in both models by a decreased cumulative probability of inter-event intervals for inhibitory currents. Furthermore, reduced gene expression levels of Gabarap and Gabarapl1 were detected in Shank3-deficient mice, whereas decreased Gat1 expression level was found in prenatally VPA-exposed rats at postnatal day 5. These findings strongly support the excitatory-inhibitory imbalance hypothesis in ASD. Thus, genetic or environmentally induced GABAergic changes in the hippocampus may underlie hippocampus-dependent social memory alterations in ASD.

Tranexamic acid (TXA) has been associated with an increased risk of postoperative seizures. However, the neuronal mechanisms underlying its proconvulsant effects remain unclear. This study investigated the dose-dependent effects of TXA on neuronal excitability in a penicillin-induced epileptiform activity model and its interaction with GABA_A and GABA_B receptor pathways using electrophysiological techniques. Sixty-two male Sprague-Dawley rats were divided into nine experimental groups. Under urethane anesthesia (1.25 g/kg), a craniotomy exposed the left cerebral cortex for stereotaxic implantation. Interictal epileptiform activity was induced via intracortical penicillin injection (500 IU) in all groups except the TXA-only control. Following stabilization of epileptiform activity, groups received intracerebroventricular (i.c.v.) injections of either saline (penicillin control), TXA (50, 100, or 200 µg), or combinations of 200 µg TXA with GABA_A (ago: 10 µg muscimol, ant: 10 µg bicuculline) and GABA_B (ago: 10 µg baclofen, ant: 10 µg phaclofen) receptor agonist or antagonist. Electrocorticogram (ECoG) recordings were acquired for at least 60 min post-injection. Epileptiform activity latency, spike frequency, and amplitude were analyzed across groups. The 200 µg TXA-only group exhibited epileptiform discharges with a significantly shorter onset latency (60 ± 28 s) compared to the penicillin control (p < 0.05). Co-administration of the GABA_B agonist baclofen with TXA significantly reduced spike frequency (p < 0.01), whereas the GABA_B antagonist phaclofen increased it (p < 0.01). In contrast, neither the GABA_A agonist muscimol nor the antagonist bicuculline altered spike frequency. In conclusion, 200 µg of TXA administered intracortically to Sprague-Dawley rats alone caused epileptiform discharges. According to the findings obtained from the interaction studies within the scope of this study, TXA was evaluated to cause epileptiform activity by blocking the GABA_A receptor. These findings are expected to contribute to the development of safer dosing strategies and potential preventive interventions for the clinical use of TXA.

Alzheimer’s disease (AD) is one of the most common neurodegenerative disorders. The accumulation of amyloid-beta (Aβ) deposits in the brain is considered a major cause of the disease. Acetylcholinesterase (AChE) plays a unique role in AD pathogenesis: (1) its overactivity reduces acetylcholine (ACh) levels, leading to degeneration of the cholinergic system, and (2) it is consistently colocalized with amyloid deposits, where it may promote amyloid fibril formation. AChE binds to Aβ, thereby facilitating both fibril assembly and the resulting neurotoxicity. It is widely accepted that compounds inhibiting AChE activity or binding to the enzyme may serve as effective therapeutic agents for AD. A new group of AChE inhibitors—N-substituted amino acid dialkyl-aminoalkylamides—has been developed. In this study, we evaluated the neuroprotective properties of three novel cholinesterase (ChE) inhibitors: TVA (N-benzoyl-DL-valine-dimethylaminoethylamine iodometilate), TVS (1-diethylaminoethyl-2-phenyl-4-benzylidene-5-imidazolone), and TVV (2-phenyl-4-(p-toluenesulfonyloxybenzylidene)-5-imidazolone) using a primary rat hippocampal neuron culture model treated with Aβ25–35. We investigated the concentration-dependent effects of these compounds. The resulting dose–response curves had two distinct phases: lower concentrations (< 10⁻² mg/ml) exhibited anti-amyloid or therapeutic activity, while higher concentrations (> 10⁻² mg/ml) were toxic to hippocampal neurons. The beneficial effects were confirmed by multiple assays, including LDH activity, lactate content, cresyl violet staining, Calcein AM/PI double staining, and NF/GFAP immunostaining. TVA and TVV at 10⁻² mg/ml effectively attenuated Aβ25–35-induced (20 µg/ml) neuronal damage. Our findings demonstrate that members of the newly synthesized N-substituted amino acid dialkyl-aminoalkylamide family—particularly TVA and TVV—possess strong protective activity against Aβ25–35-induced toxicity in primary rat hippocampal neurons. Interaction with AChE, leading to either enzyme inhibition or conformational changes, is proposed as the primary mechanism underlying their neuroprotective effects.

The incidence of depression is increasing year by year and has become a major problem threatening global public health. However, the limited efficacy of existing antidepressant drugs, accompanied by significant side effects and dependence, has prompted researchers to search for safer and more effective drugs. Recent studies have shown that neuroinflammation plays a key role in the pathological mechanisms of depression, suggesting that anti-inflammatory drugs may have potential for treating depression. Glabridin, the main active ingredient in Glycyrrhiza glabra, has significant anti-inflammatory and neuroprotective effects, but its antidepressant effects and mechanisms have not been fully elucidated. In the present study, we used a combination of network pharmacological prediction and in vivo experiments to investigate the ameliorative effect of glabridin on chronic unpredictable mild stress (CUMS)-induced depressive-like behaviours in mice and the possible molecular mechanisms. The experimental results showed that glabridin significantly ameliorated the symptoms of pleasure deficit and behavioral despair in CUMS mice, as evidenced by an increase in sucrose preference and a significant reduction in tail-hanging immobility time and forced swimming immobility time. In addition, glabridin effectively alleviated CUMS-induced neuronal damage in the hippocampal region and significantly reduced the expression of inflammatory factors, such as IL-1β, IL-6, and IL-18, suggesting that it could reduce the neuroinflammatory response. Network pharmacological analysis revealed that MAPK and NF-κB signaling pathways may be the key pathways for the antidepressant effect of glabridin. Further Western blot validation showed that glabridin inhibited the activation of the P38MAPK/NF-κB pathway in the hippocampus and reduced the phosphorylation level of related proteins. Overall, we provide evidence suggesting that the antidepressant mechanism of glabridin may be closely associated with multiple pathways, including downregulation of MAPK/NF-κB pathway activity, inhibition of inflammatory factor expression, and neurotransmitter regulation. This study offers new insights into the therapeutic potential of glabridin for treating depression.

Astrocytes have important functions in the metabolism and antioxidative defence of the brain. Three redox pairs and the ratio of the reduced and oxidized partners in each pair are essential for astrocytic redox metabolism, GSx (glutathione (GSH) plus glutathione disulfide (GSSG)), NADx (NADH plus NAD⁺) and NADPx (NADPH plus NADP⁺). In order to elucidate the interactions between the three redox pairs in astrocytes, we first analysed the basal levels of the six redox co-substrates for cultured primary rat astrocytes by using sensitive and specific enzymatic cycling assays. In untreated cultures, the basal specific contents of GSx, NADPx and NADx were 44.7 ± 8.2 nmol/mg protein, 0.64 ± 0.09 nmol/mg protein and 2.91 ± 0.40 nmol/mg protein, with the reduced co-substrates accounting for 97 ± 3%, 37 ± 14% and 28 ± 10% of the total amounts, respectively. Exposure of cultured astrocytes to oxidative stress (100 µM H₂O₂ in the presence of the pentose-phosphate pathway inhibitor G6PDi-1) caused a rapid and severe but transient oxidation of GSH to GSSG. This increase was accompanied by a doubling of the total pool of NADPx on the expense of the cellular NADx pool, suggesting that NAD⁺ was phosphorylated to NADP⁺ under these conditions. Testing for NAD kinase (NADK) activity in lysates of cultured astrocytes revealed that the enzyme is present with a specific v_max activity of around 1 nmol/(min x mg protein) and has K_M-values of 1.30 ± 0.19 mM for NAD⁺ and 2.71 ± 0.18 mM for ATP. Preincubation of astrocytes with thionicotinamide, the precursor for the cellular synthesis of the NADK inhibitor thio-NADP, prevented the transient oxidative stress-induced phosphorylation of NAD⁺ to NADP⁺. These data demonstrate that the NADPx pool can be increased in cultured astrocytes during oxidative stress by NADK-mediated phosphorylation of NAD⁺, providing experimental evidence for an additional interaction of the main astrocytic redox pairs during oxidative stress.

The current study aimed to evaluate the in-vitro toxicity and in-vivo antidiabetic effects of a standardized extract from Eugenia uniflora (E. uniflora) fruit, comparing its efficacy to metformin (Met), a widely used anti-hyperglycemic drug. First, toxicity of the extract was determined by MTT assay in 3T3 cell line and primary astrocyte culture. Then Wistar rats were divided into four groups: I- Control, II- type 2 diabetes mellitus (T2DM), III- T2DM + Met and IV- T2DM + E. uniflora. To induce T2DM, groups II, III and IV received a high fat diet (HFD) for 3 weeks followed by a single intraperitoneal (i.p.) dose of streptozotocin (STZ, 35 mg/kg). Animals of group I received normal diet and vehicle (i.p.). Group III received Met (250 mg/kg) and group IV received E. uniflora (200 mg/kg) intragastric pathway, once a day, throughout all experimental protocol. Animals from the groups I and II received water in the same volume. Results showed that cell viability was not affected. In-vivo, E. uniflora and Met prevented the change in serum levels of glucose, cholesterol, LDL, triglyceride and interleukin-6. Furthermore, extract and Met improved oxidative stress markers and antioxidant enzyme activity in the brain (cerebral cortex, hippocampus, striatum). Furthermore, extract enhanced the downstream insulin signaling pathway, including insulin receptor substrate 1, forkhead box protein O-3a, as well as activated the nuclear factor erythroid 2-related factor 2 in the cerebral cortex. This study indicates that E. uniflora extract may have potential in preventing complications associated with T2DM; nevertheless, additional studies are required to confirm these effects and establish their clinical significance.

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