Pentylenetetrazole Research Articles

Neuroprotective role of chlorogenic acid against hippocampal neuroinflammation, oxidative stress, and apoptosis following acute seizures induced by pentylenetetrazole.

This study investigated the neuroprotective effect of chlorogenic acid (CGA) on pentylenetetrazole (PTZ)-induced acute epileptic seizures in mice. Epileptic animals received CGA (200mg/kg) or sodium valproate (standard antiepileptic agent, 200mg/kg) for four weeks. Results revealed that pre-administration of CGA significantly reversed the behavioral changes following pentylenetetrazole (PTZ) injection. Further, CGA pre-treatment caused significant increases in acetylcholinesterase (AChE) activity and brain-derived neurotrophic factor (BDNF) levels, along with marked increases in dopamine, norepinephrine, and serotonin levels. Additionally, the increased antioxidant enzymes activities, along with higher glutathione (GSH) contents and upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) gene expression, were indicative of a notable improvement in the cellular antioxidant defense in mice treated with CGA. These results were associated with lowered malondialdehyde (MDA) and nitric oxide (NO) levels. Moreover, epileptic mice that received CGA showed significant declines in the content of interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and nuclear factor kappa-B (NF-κB), besides downregulating inducible nitric oxide synthase (iNOS) expression. Remarkably, CGA counteracted hippocampal apoptosis by lessening the levels of pro-apoptotic biomarkers [Bcl-2-associated X protein (Bax) and caspase-3] and increasing the anti-apoptogenic marker level of B-cell lymphoma 2 (Bcl-2). The hippocampal histopathological findings corroborated the abovementioned changes. In sum, these findings suggest that CGA could mediate the neuroprotective effect against PTZ-induced epilepsy via modulation of neurotransmitters, oxidative damage, neuroinflammation, and apoptosis. CGA, therefore, could be considered a valuable antiepileptic therapeutic supplement.

Induction of seizures and initiation of epileptogenesis by pilocarpine in zebrafish larvae.

Preclinical models of seizures and epilepsy in rodents contributed substantially to the discovery of currently available antiseizure medications. These were also broadly used for investigation of processes of epileptogenesis. Nevertheless, rodent models pose some limitations, thus, new models using alternative species are in high demand. The aim of this study was to describe a new model of seizures/epilepsy induced by the cholinomimetic agent, pilocarpine (PILO), in larval zebrafish. Local field potential (LFP) recordings were conducted to analyze electroencephalographic discharges and correlate it with larval behavior. Hematoxylin and eosin (H&E) staining, as well as TUNEL staining were performed to analyze morphology and apoptosis, respectively. Real-time quantitative polymerase chain reaction (qRT-PCR) was undertaken for gene expression analysis. Acute exposure to PILO, in a concentration-dependent manner, induces electroencephalographic discharges in larval zebrafish, which behaviorally manifest as decreased locomotion and moving time, but enhanced movement velocity. The PILO-induced seizure-like activity is behaviorally distinct from this induced by the application of chemoconvulsant pentylenetetrazole (PTZ). Zebrafish larvae previously exposed to PILO (2 h), after a washing out period, exhibit spontaneous, unprovoked discharges and apoptotic changes in their brains. Here, we comprehensively investigated a new model of PILO-induced seizures/epilepsy in larval zebrafish. We propose that this model may be used to study epileptogenesis and for antiseizure drug screening purposes.

Machine learning enables high-throughput, low-replicate screening for novel anti-seizure targets and compounds using combined movement and calcium fluorescence in larval zebrafish.

Identifying new, more efficacious anti-seizure medications (ASMs) is challenging, partly due to limitations in animal-based assays. Zebrafish (Danio rerio) can serve as a model of chemical and genetic seizures, but methods for detecting seizure-like activity in zebrafish, though powerful, have been hampered by low sensitivity (locomotor/behavioral assays) or low-throughput (tectal electrophysiology or calcium fluorescence microscopy). To address these issues, we developed a novel approach to assay seizure-like activity using combined locomotor and calcium fluorescence features, measured simultaneously from unrestrained larval zebrafish using a 96-well fluorescent plate reader. Using custom software to track fish movement and changes in fluorescence (deltaF/F0) from high-speed time-series (12.6Hz), we trained logistic classifiers using elastic net regression to distinguish seizure-like activity from non-seizure related changes based on event-specific and subject-specific features in response to the GABAAR antagonist, pentylenetetrazole (PTZ). We demonstrate that a classifier trained on combined movement and fluorescence data achieves high accuracy ("PTZ M+F"; area-under-curve receiver-operator characteristic (AUC-ROC): 0.98; F1 score: 0.912) and out-performs classifiers trained on movement ("PTZ M"; AUC-ROC: 0.9, F1: 0.9) or fluorescence features alone ("PTZ F"; AUC-ROC 0.96; F1: 0.87). The rate of classified seizure-like events increases as a dose-response to PTZ (serial dose escalation, 0, 2.5mM, 15mM) and is strongly suppressed by ASM treatment (valproic acid, VPA; tiagabine, TGB). At high-dose PTZ, we show that VPA reduces seizure-like activity defined by either "PTZ M+F" or "PTZ M" classifiers. Meanwhile, TGB selectively reduces events defined by the "PTZ M+F" classifier, paralleling previous reports that TGB reduces electrographic but not locomotor seizures and highlighting the potential for our approach to combine features of previously orthogonal assays. Using ASM benchmark data, we employ bootstrap simulation to calculate the expected statistical power of our method as a function of sample size. We demonstrate that anti-seizure responses (robust strictly standardized mean difference, RSSMD, versus control) with magnitudes similar to those associated with VPA or TGB can be reliably detected (true positive rate (TPR) > 90%) with as few as N=4 biological replicates per group, while maintaining a 5% false positive rate. In a prospective test screen with 3-6 replicates per group and on-plate controls, the anti-seizure effect of 4 out of 5 tested ASMs (CBZ, LEV, LZP, TGB) was detected. In summary, we demonstrate a simple high-throughput approach to whole organism anti-seizure phenotyping combining two previously reported metrics to facilitate screens for novel anti-seizure interventions in zebrafish.

Intracerebroventricular administration of the exercise hormone irisin or acute strenuous exercise alleviates epileptic seizure-induced neuroinflammation and improves memory dysfunction in rats

BackgroundStatus epilepticus is a common and potentially life-threatening neurological emergency with a high risk for cognitive and neurobiological impairment. Our aim was to evaluate the neuroprotective effects of centrally administered irisin and acute exhausting exercise against oxidative brain injury and memory dysfunction due to a pentylenetetrazole (PTZ)-induced single seizure. Male Sprague Dawley rats with intracerebroventricular (icv) cannulas were randomly divided into intraperitoneally (ip) saline-injected control and PTZ-injected (45 mg/kg) seizure groups. Both the control and PTZ groups were then treated with irisin (7.5 µg/kg, 2 µl, icv), saline (2 µl, icv) or were forced to an acute bout of strenuous exercise before the ip injection of saline (control) or PTZ. Seizures were evaluated using the Racine score. To evaluate memory performance, a passive avoidance test was performed before and after PTZ injection. Following euthanasia at the 24th hour of seizure induction, brain tissues were removed for histopathological examination and for evaluating oxidative damage, antioxidant capacity, and neurotransmitter levels.ResultsGlutamate/GABA imbalance observed in PTZ rats was corrected by irisin administration (p < 0.001/p < 0.01), while irisin prevented the generation of reactive oxygen species and lipid peroxidation (p < 0.05 − 0.001) and replenished the antioxidant catalase and glutathione levels (p < 0.01–0.01) in the cerebral tissue, and reduced the histologically evident neuronal injury due to a single seizure (p < 0.05 − 0.01). Irisin also delayed the onset of seizures (p < 0.05) and improved memory dysfunction (p < 0.05), but did not affect the severity of seizures. The acute exhaustive swimming exercise completed before PTZ-seizure depressed glutamate level (p < 0.001), maintained the oxidant/antioxidant balance, alleviated neuronal injury (p < 0.05 − 0.01) and upregulated cerebral BDNF expression (p < 0.05).ConclusionIn conclusion, acute high-intensity exercise or exogenously administered irisin provides neuroprotection by maintaining the balance of excitatory/inhibitory neurotransmitters and oxidant/antioxidant systems.

Protective effect of crocin-loaded nanoparticles in rats following epileptic seizures: Biochemical, behavioral and histopathological outcomes

Epilepsy is a condition resulting from complex interactions involving excessive neuronal electrical activity and oxidative stress, which can lead to chronic neurological conditions. This study evaluates crocin encapsulated in SLNC for neuroprotective and countering pentylenetetrazole (PTZ) -induced oxidative damage. The rats were pre-treated with SLNC and FC (25, 50 mg/kg/day; P.O.) for 28 days before being induced with PTZ. Various standard tests were conducted to assess their behavioral functions, such as Y-maze, Open field test (OFT), and elevated plus maze (EPM) tests. ELISA measured brain tissue catalase activity (CAT) and nitric oxide status (NO). The expression of Nuclear factor kappa B (NF-κB) and the number of dendrite spines were examined through Immunohistochemical and Golgi–Cox staining, respectively. The Pretreating rats with SLNC plus PTZ significantly boosted memory and reduced anxiety levels in Y-maze, OFT, and EPM tests. In addition, it decreased NO levels and increased CAT levels. SLNC also showed a significant decrease in NF-κB expression and an increase in neurons and the number of spines. The positive effects of SLNC in improving memory and learning deficits after PTZ injection can be attributed to its anti-inflammatory and anti-oxidative effects.

A Study on the Anticonvulsant Activity of the Simultaneous Administration of Melatonin, Agmatine, and Vitamin D3 on Pentylenetetrazole-Induced Seizures in Mice

Background: Epilepsy is a neurological disorder characterized by a decreased level of vitamins and endogenous antioxidants and an enhanced level of oxidative stress. Objective: We designed this study to define the effects of combining melatonin, vitamin D3 (Vit D3), and agmatine on seizures caused by pentylenetetrazole (PTZ) in male NMRI mice. Methods: The experimental groups were as follows: the first group was administered normal saline (0.5 ml, i.p.) on the last day of the trial, and the second group was administered intraperitoneal PTZ (60 mg/kg) on that day. Pre-treatment with diazepam (4 mg/kg), vitamin D3 (6000 IU/kg, p.o.), agmatine (40 mg/kg, p.o.), and melatonin (20 mg/kg, p.o) was given to the next four groups before injecting PTZ (60 mg/kg, i.p.). The last group received a compound therapy of vitamin D3, melatonin, and agmatine before PTZ injection. Afterward, the latency, duration, and oxidative stress indications were evaluated in the brains of mice. Results: Treatments enhanced the latency of seizure and reduced seizure duration in comparison with the PTZ group; the compound group increased seizure latency more than Vit D3, agmatine, and melatonin groups and decreased the duration more than pre-treatment with Vit D3. We observed enhancement in superoxide dismutase (SOD) and catalase (CAT) activity in the treatment groups, while in the combination group, elevating CAT activity was comparable with Vit D3 and agmatine groups. The malondialdehyde level decreased in diazepam, agmatine, melatonin, and combination groups. Conclusion: The compound treatment was more efficient than each one alone in improving PTZinduced seizure, which may result from suppressing oxidative stress.

Exploring Valeriana species: Unraveling anticonvulsant potential through phytochemistry and pharmacology

Background and aims: The Valerianaceae comprises about 300 species of annual and perennial plants found worldwide. Several species are utilized for biological purposes, while others are consumed. The various Valeriana species have different therapeutic effects, including sleep aid, sedative and anxiolytic, and anticonvulsant effects. The study intends to review the phytochemistry, pharmacological activities, and molecular pathways of these plants to explore their potential as therapeutic options for seizures and epilepsy. Methods: Until 2023, all relevant information about Valeriana species was gathered from PubMed, Scopus, Web of Science, and Embase. Valerianaceae, Valeriana, valeric acid, and Valeriana officinalis, phytochemical composition, in vivo investigations, epilepsy, neuroprotective, anticonvulsant, GABA, seizure, and preclinical and clinical research were among the search terms utilized for this review. Results: Based on the results obtained from the studies conducted in this field, significant anticonvulsant effects of various compounds extracted from the Valeriana species have been observed in multiple animal models, including pentylenetetrazole (PTZ)- and maximal electroshock (MES)-induced seizures in mice, rats, and zebrafish. It has also been determined that the molecular and pharmacological mechanisms involved in these anti-epileptic effects are increasing the GABA pathway, inhibiting the NMDA receptor and adenosine pathways, and nitric oxide (NO) modulation. Moreover, these compounds synergize with clonazepam, diazepam, phenobarbital, and phenytoin. Conclusion: It is recommended to prepare proper drug forms and study its anticonvulsant effects in clinical studies.

“Sigma-1 receptor modulation by clemastine highlights its repurposing as neuroprotective agent against seizures and cognitive deficits in PTZ-kindled rats”

Epilepsy is a neurological disorder characterized by recurrent spontaneous seizures alongside other neurological comorbidities. Cognitive impairment is the most frequent comorbidity secondary to progressive neurologic changes in epilepsy. Sigma 1 receptors (σ1 receptors) are involved in the neuroprotection and pathophysiology of both conditions and targeting these receptors may have the potential to modulate both seizures and comorbidities. The current research demonstrated the effect of clemastine (10 mg/kg, P.O.), a non-selective σ1 receptor agonist, on pentylenetetrazol (PTZ) (35 mg/kg, i.p., every 48 h for 14 doses)-kindling rats by acting on σ1 receptors through its anti-inflammatory/antioxidant capacity. Clemastine and phenytoin (30 mg/kg, P.O.) or their combination were given once daily. Clemastine treatment showed a significant effect on neurochemical, behavioural, and histopathological analyses through modulation of σ1 receptors. It protected the kindling animals from seizures and attenuated their cognitive impairment in the Morris water maze test by reversing the PTZ hippocampal neuroinflammation/oxidative stress state through a significant increase in inositol-requiring enzyme 1 (IRE1), x-box binding protein 1 (XBP1), along with a reduction of total reactive oxygen species (TROS) and amyloid beta protein (Aβ). The involvement of σ1 receptors in the protective effects of clemastine was confirmed by their abrogation when utilizing NE-100, a selective σ1 receptor antagonist. In light of our findings, modulating σ1 receptors emerges as a compelling therapeutic strategy for epilepsy and its associated cognitive impairments. The significant neuroprotective effects observed with clemastine underscore the potential of σ1 receptor-targeted treatments to address both the primary symptoms and comorbidities of neurological disorders.

Effects of acute administration of 4-allyl-2,6-dimethoxyphenol in mouse models of seizures

Epilepsy, a chronic neurological disorder characterized by recurrent unprovoked seizures, presents a substantial challenge in approximately one-third of cases exhibiting resistance to conventional pharmacological treatments. This study investigated the effect of 4-allyl-2,6-dimethoxyphenol, a phenolic compound derived from various natural sources, in different models of induced seizures and its impact on animal electroencephalographic (EEG) recordings. Adult male Swiss albino mice were pre-treated (i.p.) with a dose curve of 4-allyl-2,6-dimethoxyphenol (50, 100, or 200 mg/kg), its vehicle (Tween), or standard antiepileptic drug (Diazepam; or Phenytoin). Subsequently, the mice were subjected to different seizure-inducing models – pentylenetetrazole (PTZ), 3-mercaptopropionic acid (3-MPA), pilocarpine (PILO), or maximal electroshock seizure (MES). EEG analysis was performed on other animals surgically implanted with electrodes to evaluate brain activity. Significant results revealed that animals treated with 4-allyl-2,6-dimethoxyphenol exhibited increased latency to the first myoclonic jerk in the PTZ and PILO models; prolonged latency to the first tonic-clonic seizure in the PTZ, 3-MPA, and PILO models; reduced total duration of tonic-clonic seizures in the PTZ and PILO models; decreased intensity of convulsive seizures in the PTZ and 3-MPA models; and diminished mortality in the 3-MPA, PILO, and MES models. EEG analysis indicated an increase in the percentage of total power attributed to beta waves following 4-allyl-2,6-dimethoxyphenol administration. Notably, the substance protected from behavioral and electrographic seizures in the PTZ model, preventing increases in the average amplitude of recording signals while also inducing an increase in the participation of theta and gamma waves. These findings suggest promising outcomes for the tested phenolic compound across diverse pre-clinical seizure models, highlighting the need for further comprehensive studies to elucidate its underlying mechanisms and validate its clinical relevance in epilepsy management.

Neuroprotective effect of cinnamic alcohol: A bioactive compound of Cinnamomum spp. essential oil

Cinnamic alcohol (CA) is a phenylpropanoid found in the essential oil of the bark of the genus Cinnamomum spp. Schaeff. (Lauraceae Juss.), known as cinnamon. To evaluate the neuroprotective effect of CA and its possible mechanism of action on mice submitted to the pentylenetetrazole (PTZ) induced epileptic seizures model. Behavioral, neurochemical, histomorphometric and immunohistochemistry analysis were carried out. The administration of CA (50–200 mg/kg, i.p., 30 min prior to PTZ and 0.7–25 mg/kg, i.p., 60 min prior to PTZ) increased the latency to seizure onset and the latency to death. The effects observed with CA treatment at 60 min were partially reversed by pretreatment with flumazenil. Furthermore, neurochemical assays indicated that CA reduced the concentration of malondialdehyde and nitrite, while increasing the concentration of reduced glutathione. Finally, histomorphometric and immunohistochemistry analysis revealed a reduction in inflammation and an increase in neuronal preservation in the hippocampi of CA pre-treated mice. Taken together, the results suggest that CA seems to modulate the GABAA receptor, decrease oxidative stress, mitigate neuroinflammation, and reduce cell death processes.

Toll-Like Receptor 1/2 Postconditioning by the Ligand Pam3cys Tempers Posttraumatic Hyperexcitability, Neuroinflammation, and Microglial Response: A Potential Candidate for Posttraumatic Epilepsy.

Toll-like receptors (TLRs) are activated by endogenous molecules released from damaged cells and contribute to neuroinflammation following traumatic brain injury (TBI) and epilepsy. TLR1/2 agonist tri-palmitoyl-S-glyceryl-cysteine (Pam3cys) is a vaccine adjuvant with confirmed safety in humans. We assessed impact of TLR1/2 postconditioning by Pam3cys on epileptogenesis and neuroinflammation in male rats, 6, 24, and 48h after mild-to-moderate TBI. Pam3cys was injected into cerebral ventricles 30min after controlled cortical impact (CCI) injury. After 24h, rats underwent chemical kindling by once every other day injections of pentylenetetrazole (PTZ) 35mg/kg until development of generalized seizures. Number of intact neurons, brain expression of proinflammatory cytokine TNF-α, anti-inflammatory cytokine IL-10, and marker of anti-inflammatory microglia arginase1 (Arg1) were determined by immunoblotting. Astrocytes and macrophage/microglia activation/polarization at the contused area was assessed by double immunostaining with Iba1/Arg1, Iba1/iNOS and GFAP/iNOS, specific antibodies. The CCI-injured rats became kindled by less number of PTZ injections than sham-operated rats (9 versus 14 injections, p < 0.0001). Pam3cys treatment returned the accelerated rate of epileptogenesis in TBI state to the sham level. Pam3cys decreased neural death 48h after TBI. It decreased TNF-α (6h post-TBI, p < 0.01), and up-regulated IL-10 (p < 0.01) and Arg1 (p < 0.05) 48h after TBI. The iNOS-positive cells decreased (p < 0.001) whereas Iba1/Arg1-positive cells enhanced (p < 0.01) after Pam3cys treatment. Pam3cys inhibits TBI-accelerated acquisition of seizures. Pam3cys reprograms microglia and up-regulates anti-inflammatory cytokines during the first few days after TBI. This capacity along with the clinical safety, makes Pam3cys a potential candidate for development of effective medications against posttraumatic epilepsy.

Caspase-1 inhibitor CZL80 protects against acute seizures via amplifying the inhibitory neural transmission

Current anti-seizure medications (ASDs) primarily target ion channels or neurotransmissions; however, their practicability is limited by unwanted side-effects and pharmacoresistance. Cumulative evidence has proposed pro-inflammatory caspase-1 as a potential target for developing ASDs. In this study, we showed that the small-molecular caspase-1 inhibitor CZL80 can prevent seizures in various models including the maximal electroshock (MES), the pentylenetetrazol (PTZ), and the amygdaloid kindled models. Specifically, we discovered that CZL80 prevented death, reduced the duration of generalized seizures, and increased the threshold of generalized seizures in a dose-dependent manner in the MES model. In the PTZ model, CZL80 decreased the seizure stages, prolonged the latency to stage 4 seizures, and decreased the death rate. And in amygdaloid kindled rats, CZL80 inhibited the seizure stages, shortened the durations of both generalized seizures and after-discharges. And the anti-seizure efficacy of CZL80 was diminished in caspase-1 knockout mice. In vitro electrophysiology recordings revealed that CZL80 was able to decreased the excitability of glutamatergic pyramidal neurons, as denoted by reducing the spontaneous neuronal firings and increasing the rheobase injected currents to elicit action potentials. Furthermore, CZL80 was able to increase the amplitudes of inhibitory post-synaptic currents (IPSC), while the excitatory post-synaptic currents (EPSC) were not influenced. Lastly, daily administration of CZL80 for 3 weeks did not influence the normal locomotor functions in mice. In sum, our results highlighted CZL80 as a potential anti-seizure therapy with therapeutic significance.

Disruption of adenosine metabolism increases risk of seizure-induced death despite decreased seizure severity.

Respiratory arrest plays an important role in sudden unexpected death in epilepsy (SUDEP). Adenosine is of interest in SUDEP pathophysiology due to its influence on seizures and breathing. The objective of this investigation was to examine the role of adenosine in seizure severity, seizure-induced respiratory disruption, and seizure-induced death using mouse models. Understanding adenosinergic contributions to seizure cessation and seizure-induced death may provide insights into how SUDEP can be prevented while avoiding increased seizure severity. Our approach was to examine: (1) seizure severity and seizure-induced death after 15 mA electroshock seizures and during repeated pentylenetetrazol (PTZ) administration in wild-type mice (Adk+/+) and transgenic mice with reduced adenosine metabolism (Adk+/-); (2) the postictal hypercapnic ventilatory response (HCVR) in wild-type mice (the postictal HCVR could not be examined in Adk+/- mice due to their high mortality rate); and (3) the effects of adenosinergic drugs on seizure severity and seizure-induced death following maximal electroshock (MES). Adk+/- mice were more vulnerable to seizure-induced death in the 15 mA electroshock and repeated PTZ models. Despite increased mortality, Adk+/- mice had comparable seizure severity in the PTZ model and reduced seizure severity in the 15 mA electroshock model. Breathing and HCVR were suppressed by 15 mA electroshock seizures in wild-type mice. Pharmacological inhibition of adenosine metabolism decreased MES seizure severity but did not increase mortality. A1 selective and nonselective adenosine receptor antagonists increased seizure-induced death following MES. Adenosine has opposing effects on seizure severity and seizure-induced death. On the one hand, our seizure severity data highlight the importance of adenosine in seizure suppression. On the other hand, our mortality data indicate that excessive extracellular adenosine signaling can increase the risk of seizure-induced respiratory arrest.

Facile Construction of a Double-Heterojunction Perovskite Quantum Dot System for Efficient Photocatalytic Cr6+ Reduction.

Based on their excellent stability, high carrier mobility, and wide photoresponse range, composites formed by embedding perovskite quantum dots (PQDs) into metal-organic frameworks (PQDs@MOF) show great development potential in the field of photocatalysis, including the toxic hexavalent chromium (Cr6+) degradation, CO2 reduction, H2 production, etc. However, the rapid recombination of photogenerated carriers is still a major obstacle to the improvement of photocatalytic performance, and the internal mechanism of photocatalysis is still unclear. In this work, we construct a novel double heterojunction photocatalyst by encapsulating CsPbBr3 PQDs in Zr-based metal-organic frameworks (UiO-67) and loading additional hole-acceptor pentylenetetrazol (PTZ). Spontaneous photoinduced charge-transfer and separation between interfaces are confirmed by time-resolved photoluminescence and transient absorption spectroscopy. Furthermore, compared with pure UiO-67, the photoactivity of CsPbBr3 PQDs@UiO-67@PTZ increased 3-fold due to the long-lived charge-separated state. Our findings provide a new guideline for the design of PQDs@MOF-based photocatalysts with long-lived photogenerated carriers and outstanding photocatalytic activity.

Brain connectivity analysis in preictal phases of seizure induced by pentylenetetrazol in rats

Abnormal patterns of brain connectivity characterize epilepsy. However, little is known about these patterns during the stages preceding a seizure induced by pentylenetetrazol (PTZ). To investigate brain connectivity in male Wistar rats during the preictal phase of PTZ-induced seizures (60 mg/kg), we recorded local field potentials in the primary motor (M1) cortex, the ventral anterior (VA) nucleus of the thalamus, the hippocampal CA1 area, and the dentate gyrus (DG) during the baseline period and after PTZ administration. While there were no changes in power density between the baseline and preictal periods, we observed an increase in directional functional connectivity in theta from the hippocampal formation to M1 and VA, as well as in middle gamma from DG to CA1 and from CA1 to M1, and also in slow gamma from M1 to CA1. These findings are supported by increased phase coherence between DG-M1 in theta and CA1-M1 in middle gamma, as well as enhanced phase-amplitude coupling of delta-middle gamma in M1 and delta-fast gamma in CA1. Interestingly, we also noted a slight decrease in phase synchrony between CA1 and VA in slow gamma. Together, these results demonstrate increased functional connectivity between brain regions during the PTZ-induced preictal period, with this increase being particularly driven by the hippocampal formation.

ABCG2 shields against epilepsy, relieves oxidative stress and apoptosis via inhibiting the ISGylation of STAT1 and mTOR

The transporter protein ABC subfamily G member 2 (ABCG2) is implicated in epilepsy; however, its specific role remains unclear. In this study, we assessed changes in ABCG2 expression and its role in epilepsy both in vitro and in vivo. We observed an instantaneous increase in ABCG2 expression in epileptic animals and cells. Further, ABCG2 overexpression significantly suppressed the oxidative stress and apoptosis induced by glutamate, kainic acid (KA), and lipopolysaccharide (LPS) in neuronal and microglia cells. Furthermore, inhibiting ABCG2 activity offset this protective effect. ABCG2-deficient mice (ABCG2−/−) showed shorter survival times and decreased survival rates when administered with pentylenetetrazole (PTZ). We also noticed the accumulation of signal transducer and activator of transcription 1 (STAT1) and decreased phosphorylation of mammalian target of rapamycin kinase (mTOR) along with increased ISGylation in ABCG2−/− mice. ABCG2 overexpression directly interacted with STAT1 and mTOR, leading to a decrease in their ISGylation. Our findings indicate the rapid increase in ABCG2 expression acts as a shield in epileptogenesis, indicating ABCG2 may serve as a potential therapeutic target for epilepsy treatment.

Chronic stress intensify PTZ-induced seizures by triggering neuroinflammation and oxidative stress

BackgroundEpilepsy is a paroxysmal abnormal hypersynchronous electrical discharge characterized by recurrent seizures. It affects more than 50 million people worldwide. Stress is the leading cause of neurodegeneration and can produce seizures that may lead to or aggravate epilepsy. Inflammation plays a vital role in epilepsy by modulating oxidative stress, and levels of neuroinflammatory cytokines including NF-κB, TNF-α, and IL-1β. MethodsStress-induced changes in behavior were evaluated in mice by employing behavioral assessment tests such as an elevated plus maze, light-dark box, open field test, tail suspension test, Y-maze, novel object recognition test, and Morris water maze in pentylenetetrazole (PTZ) kindled mice. Behavioral changes in all these paradigms including seizure score, latency, and frequency showed an increase in symptoms in PTZ (35 mg/kg) induced seizures in stressed mice (RS-PTZ) as compared to PTZ, Stress, and normal animals. ResultsThe Enzyme-linked immunosorbent assay (ELISA) results confirmed increased in serum cortisol levels. Histological examinations showed neurodegenerative changes in the hippocampus and cortex regions. The spectrophotometric evaluation showed an increase in oxidative stress by decreasing antioxidant production i.e. reduced glutathione, glutathione -s- transferase, and catalase (CAT), and increasing oxidant levels such as maloaldehyde and nitric oxide. Immunohistochemistry results showed increased expression of NF-κB, TNF-α, and IL-1β in the cortex and hippocampus of mice brains. ConclusionsResults from the study conclude that stress increases the likelihood of eliciting an epileptic attack by increasing the level of reactive oxygen species and neuroinflammation.

Oral administration of crocin-loaded solid lipid nanoparticles inhibits neuroinflammation in a rat model of epileptic seizures by activating SIRT1 expression.

Epilepsy is a group of chronic neurological diseases caused by a complex set of neuronal hyper electrical activities and oxidative stress of neurons. Crocin is a natural bioactive agent of saffron with different pharmacological properties and low bioavailability. This study aimed to evaluate crocin-loaded solid lipid nanoparticles (SLNC) for neuroprotection activity and efficacy against pentylenetetrazol (PTZ)- induced epilepsy. The rats were pretreated with SLNC and pure-crocin (PC; 25 and 50 mg/kg/day; P.O.) for 28 days before PTZ induction. Behavioral functions were evaluated by passive avoidance learning (PAL) tasks. Then, total antioxidant capacity (TAC), malondialdehyde (MDA), and pro-inflammatory factors were measured in the brain tissue using ELISA kits. Gene expression levels were analyzed with real-time polymerase chain reaction and immunohistochemical assay was used to assess the protein expression of sirtuin1 SIRT 1). SLNC was prepared with an average particle size of 98.25 nm and 98.33% encapsulation efficiency. Memory deficit improved in rats treated with SLNC. Administering SLNC at 25 and 50 mg/kg significantly reduced MDA and proinflammatory cytokines while increasing TAC. Additionally, administering SLNC before treatment increased the levels of SIRT1, peroxisome proliferator-activated receptor coactivator 1α, cAMP-regulated enhancer binding protein, and brain-derived neurotrophic factor. Furthermore, SLNC administration resulted in the downregulation of caspase-3 and inflammation factor expression. Overall, the obtained results showed that SLNC has better protective effects on oxidative stress in neurons, neurocognitive function, and anti-apoptotic and neuromodulatory activity than PC, suggesting that it is a promising therapeutic strategy for inhibiting seizures.

Pentylenetetrazole-Induced Seizures in Wistar Male Albino Rats with Reference to Glutamate Metabolism.

Epilepsy is a common and heterogenous neurological disorder characterized by recurrent spontaneous seizures. Animal models like rats play a crucial role in finding of mechanism of epilepsy in different brain regions. i.e., cerebral cortex, cerebellum, hippocampus, and pons medulla. Glutamate is an important excitatory neurotransmitter in the central nervous system and also glutamate plays a vital role in neuronal development and memory. The process of neuronal death evolved by glutamate receptor activation, has been hypothesized in both acute and chronic degenerative disorders including epilepsy. Considering the multifactorial neurochemical and neurophysiological malfunctions consequent to epileptic seizures, a few antiepileptic drugs are designed, to mitigate the debilitating aspects of epilepsy. Rat model, pentylenetetrazole (PTZ), an anticonvulsant drug, was selected for the present study. Induction of epilepsy/convulsions was induced by an intraperitoneal injection of PTZ (60 mg/kg body weight) in saline. Biochemical assays performed through spectrophotometer. Glutamine and Glutamine synthetase levels were decreased in the epileptic rats brain regions i.e., hippocampus, cerebellum, cerebral cortex, and pons medulla; glutamate dehydrogenase and glutaminase levels were increased in all the regions of epilepsy induced rats. Highest values are recorded in hippocampus when compared to other brain regions. PTZ suppresses the function of Glutamine and Glutamine synthetase activities in selected brain regions of rat and enhances the activities of the glutaminase and glutamate dehydrogenase when compared to control rats.

Additive Anticonvulsive Effects of Sumatriptan and Morphine on Pentylenetetrazole-Induced Clonic Seizures in Mice.

Sumatriptan protects the brain from damage and enhance the anti-seizure effect of morphine. There is evidence that nitric oxide (NO) may mediate these effects of both drugs. In the present study, we investigated the effects of sumatriptan (0.1-20 mg/kg, intraperitoneal [i.p.]) and morphine (0.1-20 mg/kg, i.p.) alone or in combination on seizure thresholds in an in vivo model of seizure in mice. Using various NO synthase inhibitors as well as the NO precursor, we assessed possible involvement of NO signaling in these effects. Clonic seizures were induced in male Naval Medical Research Institute mice by intravenous administration of pentylenetetrazol (PTZ). Acute sumatriptan administration exerted anti-convulsive effects at 0.5 (p<0.01) and 1 mg/kg (p<0.05), but pro-convulsive effects at 20 mg/kg (p<0.05). Morphine had anti-convulsive effects at 0.5 (p<0.05) and 1 mg/kg (p<0.001), but exerted pro-convulsive effect at 20 mg/kg (p<0.05). Combination treatment with sub-effective doses of sumatriptan (0.1 mg/kg) and morphine (0.1 mg/kg) significantly (p<0.05) exerted an anti-convulsive effect. Co-administration of the NO precursor L-arginine (60 mg/kg) with sub-effective doses of sumatriptan and morphine significantly (p<0.05) increased seizure threshold compared with sumatriptan alone, but not sumatriptan+morphine group. While concomitant administration of either the non-selective NO synthase (NOS) inhibitor L-NG-nitroarginine methyl ester (5 mg/kg) or the selective inducible NOS inhibitor aminoguanidine (50 mg/kg) with combined sub-effective doses of morphine and sumatriptan produced significant anticonvulsive effects, concomitant administration with the selective neuronal NOS inhibitor 7-nitroindazole (30 mg/kg) inhibited this effect. Our data suggest a possible role for the NO signaling in the anticonvulsive effects of combined sumatriptan and morphine on the PTZ-induced clonic seizures in mice.