macrophylla root extracts in pentylenetetrazol-induced seizure models in mice

INTRODUCTION

In the present study, anticonvulsant effects of aqueous extract (AE), hydro-alcoholic crude extract (HE), and its fractions (F-CHCl3, F-EtOAc, F-MeOH) of Paeonia daurica subsp. macrophylla (P. daurica ssp. macrophylla) root examined by using a pentylenetetrazol-induced model (PTZ) on mice.

METHODS

HE and its fractions as well as AE, in concentrations of (100, 200 and 400mg/kg), valproate (Val) (100 and 200mg/kg), and saline (negative control) (10mg/kg) were injected intraperitoneally (i.p.) 30min before PTZ (80mg/kg, i.p.). The time taken before the onset of myoclonic convulsions (MC), MC duration, time taken before the onset of generalized tonic-clonic seizures (GTCS), the duration of GTCS, and the percentage of GTCS and mortality protection recorded. The plant's anticonvulsant mechanisms were assessed using flumazenil (5mg/kg, i.p.) before AE (100, 200, and 400mg/kg, i.p.) injection. GraphPad Prism software was used to compare the differences between various treatment groups with one-way analysis of variance (ANOVA) followed by Tukey-Krammer multiple comparison tests.

RESULTS

All the plant samples except F-EtOAc significantly delayed the onset and decreased the duration of PTZ-induced MCS and GTCS, and significantly reduced the GTCS and mortality rate. Pretreatment with flumazenil diminished the significant anticonvulsant effects of AE against PTZ-induced seizures.

CONCLUSIONS

It can report that extract of P. daurica ssp. macrophylla might be a helpful guide for future studies in the treatment of epilepsy.

Behavioral and neurotransmitter changes on antiepileptic drugs treatment in the zebrafish pentylenetetrazol-induced seizure model

Epilepsy, a recurrent neurological disorder involving abnormal neurotransmitter kinetics in the brain, has emerged as a global health concern. The mechanism of epileptic seizures is thought to involve a relative imbalance between excitatory and inhibitory neurotransmitters. Despite the recent advances in clinical and basic research on the pathogenesis of epilepsy, the complex relationship between the neurotransmitter changes and behavior with and without antiepileptic drugs (AEDs) during seizures remains unclear. To investigate the effects of AEDs such as levetiracetam (LEV), carbamazepine (CBZ), and fenfluramine (FFR) on key neurotransmitters in the pentylenetetrazol (PTZ)-induced seizures in adult zebrafish, we examined the changes in glutamic acid, gamma-aminobutyric acid (GABA), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), choline, acetylcholine, norepinephrine, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and adenosine. In this study, we observed that 5-HT and DA levels in the brain increased immediately after PTZ-induced seizures. Behavioral tests clearly showed that all of these AEDs suppressed the PTZ-induced seizures. Upon treatment of PTZ-induced seizures with these AEDs, CBZ decreased the glutamic acid and FFR increased the GABA levels; however, no neurotransmitter changes were observed in the brain after LEV administration. Thus, we demonstrated a series of neurotransmitter changes linked to behavioral changes during PTZ-induced epileptic seizures when LEV, CBZ, or FFR were administered. These findings will lead to a more detailed understanding of the pathogenesis of epilepsy associated with behavioral and neurotransmitter changes under AED treatment.

Antiseizure effects of Lilii Bulbus on pentylenetetrazol kindling-induced seizures in mice: Involvement of Reelin, Netrin-1, and semaphorin

Lilii Bulbus (Lilium lancifolium Thunberg) has a proneurogenic effect on the hippocampus. However, its effects on epilepsy and associated pathological features remain unknown. In this study, we investigated the antiseizure effects of a water extract of Lilii Bulbus (WELB) in mouse model of pentylenetetrazol (PTZ)-induced seizure. Mice were injected with PTZ once every 48 h until full kindling was achieved. WELB (100 and 500 mg/kg) was orally administered once daily before PTZ administration and during the kindling process. We found that WELB treatment protected against PTZ-induced low seizure thresholds and high seizure severity. Further, WELB-treated mice showed attenuated PTZ kindling-induced anxiety and memory impairment. Immunostaining and immunoblots showed that hyperactivation and ectopic migration of dentate granule cells (DGCs) were significantly reduced by WELB treatment in PTZ kindling-induced seizure mice. Staining for mossy fiber sprouting (MFS) using Timm staining and ZnT3 showed that WELB treatment significantly decreased PTZ kindling-induced MFS. Furthermore, the increased or decreased expression of proteins related to ectopic DGCs (Reelin and Dab-1), MFS (Netrin-1, Sema3A, and Sema3F), and their downstream effectors (ERK, AKT, and CREB) in the hippocampus of PTZ kindling mice was significantly restored by WELB treatment. Overall, our findings suggest that WELB is a potential antiseizure drug that acts by reducing ectopic DGCs and MFS and modulating epileptogenesis-related signaling in the hippocampus.

Grafted Sertoli cells prevent neuronal cell death and memory loss induced by seizures

Epilepsy significantly reduces the patient's quality of life, and we still need to develop new therapeutic approaches to control it. Transplantation of cells such as Sertoli cells (SCs), having a potent ability to release a variety of growth and immunoprotective substances, have made them a potential candidate to deal with neurological diseases like epilepsy. Hence, this study aims to evaluate whether SCs transplant effectively protects the hippocampus astrocytes and neurons to oppose seizure damage. For this purpose, the effects of bilateral intrahippocampal transplantation of SCs were investigated on the rats with the pentylenetetrazol (PTZ) induced seizure. After one-month, post-graft analysis was performed regarding behavior, immunohistopathology, and the distribution of the hippocampal cells. Our findings showed SCs transplantation reduced astrogliosis, astrocytes process length, the number of branches, and intersections distal to the soma of the hippocampus in the seizure group. In rats with grafted SCs, there was a drop in the hippocampal caspase-3 expression. Moreover, the SCs showed another protective impact, as shown by an improvement in pyramidal neurons' number and spatial distribution. The findings suggested that SCs transplantation can potently modify astrocytes' reactivation and inflammatory responses.

The link between seizures and prolactin: A study on the effects of anticonvulsant medications on hyperprolactinemia in rats

Seizures are a common neurological disorder that affects people of all ages. These sudden, uncontrolled electrical disturbances in the brain can cause a variety of symptoms, including convulsions, loss of consciousness, and abnormal sensations. While seizures have long been recognized as a potential cause of hormonal imbalances, recent research has shed new light on the link between seizures and prolactin. The study involved 30 adult female Wistar rats, which were divided into a control group (treated with normal saline) and four treatment groups: chronic group (treated with 30 mg/kg pentylenetetrazol intraperitoneally three days a week for 10 weeks), chronic + Levetiracetam (50 mg/kg, gavage), chronic + Cabergoline (0.05 mg/kg, gavage), and chronic + Levetiracetam (25 mg/kg) + cabergoline (0.025). The drugs were administered three days a week for 10 weeks. Field action potentials were recorded from the CA1 area of the hippocampus using eLab after anesthetizing the animals with a ketamine-xylazine combination (70 +7 mg/kg). The prolactin levels were measured using the ELISA method after serum preparation. The findings indicate that the use of levetiracetam as an anticonvulsant drug resulted in a significant decrease in the amount of prolactin and spike number of convulsive activities compared to the chronic group. However, the amplitudes of convulsive activities did not show a significant difference between the control and other treatment groups. In conclusion, investigating the possibility of subclinical seizures and utilizing anticonvulsant medications in hyperprolactinemia that is resistant to treatment are crucial in treating infertility.

Neuroprotective anticonvulsant and anxiolytic effects of octreotide in wistar rats

Somatostatin interneurons exhibited anti-epileptic activity. As a result, somatostatin agonists appear to be a promising target for antiepileptic drug development (AEDs). In this regard, we investigated the effects of octreotide, a somatostatin analog, on pentylenetetrazol (PTZ)-induced seizures in male Wistar rats. Animals were given octreotide at doses of 50 or 100 µg/kg for seven days. The anxiolytic effects of octreotide were then evaluated using open field and elevated plus-maze tests. Following that, mice were intraperitoneally given a single convulsive dosage of PTZ (60 mg/kg) and then monitored for 30 min for symptoms of seizures. Finally, the antioxidant capacity of brain tissue and histopathological changes in the hippocampus were investigated. Octreotide therapy for seven days at 50 or 100 µg/kg was more effective than diazepam in preventing acute PTZ-induced seizures (P < 0.05). Furthermore, both octreotide dosages revealed substantial anxiolytic effects in open-field and elevated plus-maze tests compared to untreated rats. Nonetheless, octreotide's anxiolytic impact was less effective than diazepam's. On the other hand, octreotide also suppressed neuronal apoptosis and attenuated oxidative stress. Our results suggest that chronic administration of octreotide has anticonvulsant, anxiolytic, and antioxidant activity in the male Wistar rat model.

N-acetyl cysteine: A new look at its effect on PTZ-induced convulsions

INTRODUCTION/AIM

Epilepsy is widely investigated as a common neurological disease requiring pharmacologically effective agents. N-acetyl cysteine (NAC), has become a remarkable molecule with its role in both antioxidant and glutaminergic modulation. There are many points and processes waiting to be revealed regarding the role of NAC in epilepsy.

MATERIALS AND METHODS

Pentylenetetrazole (PTZ) was administered to induce seizures in a total number of 48 Sprague-Dawley rats. 35 mg/kg PTZ dose as a sub-convulsive dose was administered to 24 animals to monitor EEG changes, while 70 mg/kg PTZ dose which was a convulsive dose was administered to 24 animals to determine seizure-related behavioral changes with the Racine's scale. 30 min before the seizure-induced procedure, NAC was administered at doses of 300 and 600 mg/kg as pretreatment to investigate anti-seizure and anti-oxidative effects. The spike percentage, the stage of convulsion, and the onset time of the first myoclonic jerk were evaluated to determine the anti-seizure effect. Furthermore, its effect on oxidative stress was determined by measuring both malondialdehyde (MDA) level and superoxide dismutase (SOD) enzyme activity.

RESULTS

There was a dose-dependent reduction in the seizure stage and prolonged onset time of the first myoclonic jerk in rats with NAC pretreatment. EEG recordings resulted in a dose-dependent decrease in spike percentages. Moreover, the same dose-dependent changes were observed in oxidative stress biomarkers, both 300 mg/kg NAC and 600 mg/kg decreased MDA levels and ameliorated SOD activity.

CONCLUSION

We can report that 300 mg/kg and 600 mg/kg doses of NAC are promising with their reducing effect on convulsions and have a beneficial effect by preventing oxidative stress. In addition, NAC has been also determined that this effect is dose-dependent. Detailed and comparative studies are needed on the convulsion-reducing effect of NAC in epilepsy.

Early impairments of visually-driven neuronal ensemble dynamics in the rTg4510 tauopathy mouse model

Tau protein pathology is a hallmark of many neurodegenerative diseases, including Alzheimer's Disease or frontotemporal dementia. Synaptic dysfunction and abnormal visual evoked potentials have been reported in murine models of tauopathy, but little is known about the state of the network activity on a single neuronal level prior to brain atrophy. In the present study, oscillatory rhythms and single-cell calcium activity of primary visual cortex pyramidal neuron population were investigated in basal and light evoked states in the rTg4510 tauopathy mouse model prior to neurodegeneration. We found a decrease in their responsivity and overall activity which was insensitive to GABAergic modulation. Despite an enhancement of basal state coactivation of cortical pyramidal neurons, a loss of input-output synchronicity was observed. Dysfunction of cortical pyramidal function was also reflected in a reduction of basal theta oscillations and enhanced susceptibility to a sub-convulsive dose of pentylenetetrazol in rTg4510 mice. Our results unveil impairments in visual cortical pyramidal neuron processing and define aberrant oscillations as biomarker candidates in early stages of neurodegenerative tauopathies.

Immunosuppressant Tacrolimus Treatment Delays Acute Seizure Occurrence, Reduces Elevated Oxidative Stress, and Reverses PGF2α Burst in the Brain of PTZ-Treated Rats

It is still an urgent need to find alternative and effective therapies to combat epileptic seizures. Tacrolimus as a potent immunosuppressant and calcineurin inhibitor is emerging as promising drug to suppress seizures. However, there are few reports applying tacrolimus to epilepsy and providing data for its antiseizure properties. In this study, we investigated the antiseizure effects of 5 and 10 mg/kg doses of tacrolimus treatment priorly to pentylenetetrazol (PTZ) induction of seizures in rats. As an experimental design, we establish two independent rat groups where we observe convulsive seizures following 70 mg/kg PTZ and sub-convulsive seizures detected by electroencephalography (EEG) following 35 mg/kg PTZ. Thereafter, we proceed with biochemical analyses of the brain including assessment of malondialdehyde level as an indicator of lipid peroxidation and detection of superoxide dismutase (SOD) enzyme activity and PGF2α. Tacrolimus pre-treatment dose-dependently resulted in lesser seizure severity according to Racine's scale, delayed start-up latency of the first myoclonic jerk and attenuated the spike percentages detected by EEG in seizure-induced rats. However, only the higher dose of tacrolimus was effective to restore lipid peroxidation. An increase in SOD activity was observed in the PTZ group, mediated by seizure activity per se, however, it was greater in the groups that received treatment with 5 and 10 mg/kg of Tacrolimus. PGF2α bursts following PTZ induction of seizures were reversed by tacrolimus pre-treatment in a dose-dependent manner as well. We report that the well-known immunosuppressant tacrolimus is a promising agent to suppress seizures. Comparative studies are necessary to determine the possible utilization of tacrolimus in clinical cases.

Effect of valproate on sleep patterns disturbed by epilepsy

Nocturnal epilepsy is a neurological disease that has a significant effect on sleep. Various treatments have been implemented to help mitigate these effects and improve patients' quality of life. The use of experimental animal models for epilepsy has facilitated efficacy assessment and the development of different medications to treat the symptoms of this disease. The objective of this study was to evaluate the effect of valproate on sleep patterns altered by epilepsy. Chronically implanted Wistar rats were used to study sleep patterns over three consecutive days under different experimental conditions. The animals were separated into two groups. The first day was considered the control recording; on the second day, one group received pentylenetetrazol (PTZ) alone, and the other group received valproate prior to induction of convulsive seizures with PTZ administration. The results show that in addition to its antiepileptic effect, valproate has hypnotic properties. It is considered to facilitate the action of GABAergic mechanisms to mitigate the effect of convulsive seizures and increase the occurrence of sleep.

Cannabidiol reveals a disruptive strategy for 21st century epilepsy drug discovery

Over 30 antiseizure medicines (ASMs) have been uncovered in a diversity of preclinical seizure and epilepsy models, with several critical inflection points in the 20th century fundamentally transforming ASM discovery. This commentary aims to review the historical relevance of cannabidiol's (CBD; Epidiolex) approval for epilepsy in the context of other ASMs brought to market. Further, we highlight how CBD's approval may represent an inflection point for 21st century ASM discovery. CBD is one of the main phytocannabinoids of Cannabis sativa. Unlike its related phytocannabinoid, Δ9-tetrahydrocannabinol, CBD does not exert any euphorigenic, tolerance, or withdrawal effects at anticonvulsant doses. CBD also possess marked anti-inflammatory effects, offering the tantalizing potential of a new pharmacological approach in epilepsy. For decades, hints of the anticonvulsant profile of CBD had been suggested with a small handful of studies in rodent seizure models, yet difficulties in formulation, compounded by the social and regulatory pressures related to medical use of cannabis plant-derived agents constrained any clinical implementation. Nonetheless, CBD possesses a broad antiseizure profile in preclinical seizure and epilepsy models, but the transformative impact of CBD'-s approval came because of studies in a rodent model of the orphan disease Dravet syndrome (DS). DS is a pediatric developmental epileptic encephalopathy with high mortality, frequent spontaneous recurrent seizures, and marked resistance to conventional ASMs, such as phenytoin and carbamazepine. CBD was approved for DS by the US Food and Drug Administration in 2018 after convincing efficacy was established in randomized, placebo-controlled trials in children. Because of the clinical approval of CBD as a novel, cannabis plantderived ASM for DS, CBD has revealed a new strategy in ASM discovery to reignite 21st century therapeutic development for epilepsy. In this commentary, we review the major preclinical and clinical milestones of the late 20th century that made CBD, a compound historically subjected to regulatory restrictions, a key driver of a new discovery strategy for epilepsy in the 21st century.

Spatial, temporal, and cell-type-specific expression of NADPH Oxidase isoforms following seizure models in rats

The NADPH Oxidase (NOX) enzymes are key producers of reactive oxygen species (ROS) and consist of seven different isoforms, distributed across the tissues and cell types. The increasing level of ROS induces oxidative stress playing a crucial role in neuronal death and the development of epilepsy. Recently, NOX2 was reported as a primary source of ROS production, activated by NMDA receptor, a crucial marker of epilepsy development. Here, we demonstrate spatial, temporal, and cellular expression of NOX2 and NOX4 complexes in in-vitro and in-vivo seizure models. We showed that the expression of NOX2 and NOX4 was increased in the initial 24 h following a brief seizure induced by pentylenetetrazol. Interestingly, while this elevated level returns to baseline 48 h following seizure in the cortex, in the hippocampus these levels remain elevated up to one week following the seizure. Moreover, we showed that 1- and 2- weeks following status epilepticus (SE), expression of NOX2 and NOX4 remains significantly elevated both in the cortex and the hippocampus. Furthermore, in in-vitro seizure model, NOX2 and NOX4 isoforms were overexpressed in neurons and astrocytes following seizures. These results suggest that NOX2 and NOX4 in the brain have a transient response to seizures, and these responses temporally vary depending on, seizure duration, brain region (cortex or hippocampus), and cell types.

Anti-kindling effect of Ginkgo biloba leaf extract and L-carnitine in the pentylenetetrazol model of epilepsy

Epilepsy is one of the most common serious brain disorders, affecting about 1% of the population all over the world. Ginkgo biloba extract (GbE) and L-carnitine (LC) reportedly possess the antioxidative activity and neuroprotective potential. In this report, we investigated the possible protective and therapeutic effects of GbE and LC against pentylenetetrazol (PTZ)-induced epileptic seizures in rat hippocampus and hypothalamus. Adult male albino rats were equally divided into eight groups: control, GbE (100 mg/kg), LC (300 mg/kg), PTZ (40 mg/kg), protective groups (GbE + PTZ and LC + PTZ), and therapeutic groups (PTZ + GbE and PTZ + LC). The oxidative stress, antioxidant, and neurochemical parameters, viz., malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), acetylcholine esterase (AchE), dopamine (DA), norepinephrine (NE), and serotonin (5-HT), in the hippocampal and hypothalamic regions have been evaluated. PTZ injection leads to an increase in the seizure score, the levels of MDA and NO, and to a decrease in the activity of GSH, SOD, CAT, and GPx. Besides, monoamine neurotransmitters, DA, NE, and 5-HT, were depleted in PTZ-kindled rats. Furthermore, PTZ administration caused a significant elevation in the activity of AchE. Hippocampal and hypothalamic sections from PTZ-treated animals were characterized by severe histopathological alterations and, intensely, increased the ezrin immunolabeled astrocytes. Pre- and post-treatment of PTZ rats with GbE and LC suppressed the kindling acquisition process and remarkably alleviated all the aforementioned PTZ-induced effects. GbE and LC have potent protective and therapeutic effects against PTZ-induced kindling seizures via the amelioration of oxidative/antioxidative imbalance, neuromodulatory, and antiepileptic actions.

Optimization of a locomotion-based zebrafish seizure model

BACKGROUND

Locomotor assays in zebrafish have emerged as a screening test in early drug discovery for antiseizure compounds. However, parameters differ considerably between published studies, which may explain some discrepant results with (candidate) antiseizure medications.

NEW METHOD

We optimized a locomotor-based seizure assay in zebrafish with pentylenetetrazol (PTZ) as the pharmacological proconvulsant to generate a therapeutic window in which proconvulsant-treated zebrafish larvae could be discriminated from a non-treated control. To generate a reliable control, exposure time and concentration of valproate (VPA, anticonvulsant) was optimized.

RESULTS

Wells with one or three larvae show a similar PTZ dose-dependent increase in locomotion with less variability in motility for the latter. Zebrafish immersed in 10 mM PTZ showed a significant increase in movement with a sustained effect, without any indication of toxicity. Animals treated with 3 mM VPA showed the strongest reduction of PTZ-induced movement without toxicity. The decrease in PTZ-induced locomotion was greater after 18 h versus 2 h.

COMPARISON WITH EXISTING METHOD(S)

For the larval zebrafish PTZ-induced seizure model, varying experimental parameters have been reported in literature. Our results show that PTZ is often used at toxic concentrations, and we provide instead reliable conditions to quantify convulsant behaviour using an infrared-beam motility assay.

CONCLUSIONS

We recommend using three zebrafish larvae per well to quantify locomotion in 96-multiwell plates. Larvae should preferably be exposed to 10 mM PTZ for 1 h, consisting of 30 min acclimation and 30 min subsequent recording. As positive control for anticonvulsant activity, we recommend exposure to 3 mM VPA for 18 h before administration of PTZ.

The Possible Role of Nitric Oxide signaling and NMDA Receptors in Allopurinol effect on Maximal Electroshock- and Pentylenetetrazol-Induced Seizures in Mice

Allopurinol, a uric-acid-lowering medication, has shown its efficacy in several studies suggesting that allopurinol can be prescribed as adjunctive cure meant for intractable epilepsy. The exact mechanism of allopurinol is still unknown. This study evaluates allopurinol's effect on seizure threshold, seizure incidence, and mortality rate in mice models. Moreover, the possible involvement of nitric oxide (NO) pathway and N-methyl-D-aspartate (NMDA) receptors are investigated. To evaluate the effect of allopurinol on seizure, we used the pentylenetetrazole (PTZ)-induced seizure along with maximal electroshock (MES)-induced seizure. To assess the underlying mechanism behind the allopurinol activity, we used nitric oxide synthase (NOS) substrate (L-arginine), NOS inhibitors (L-NAME, aminoguanidine, 7-nitroindazole), and NMDA receptor antagonist (MK-801). Intraperitoneal allopurinol administration at a dose of 50 mg/kg in mice showed a significant (p<0.001) anti-convulsant activity in the PTZ-induced seizure. Even though pre-treatment with L-Arginine (60 mg/kg) potentiates allopurinol's anti-convulsant effect in the PTZ-induced seizure, pre-treatment with L-NAME (10 mg/kg), aminoguanidine (100 mg/kg), and 7-nitroindazole (30 mg/kg) reversed the anti-convulsant effect of allopurinol in the PTZ-induced seizure. In addition, pre-treatment with MK-801 also decreased the anti-convulsant effect of allopurinol in the PTZ-induced seizure. While allopurinol at a dose of 50 mg/kg and 100 mg/kg did not induce protection against seizure incidence in the MES-induced seizure, it revealed a remarkable effect in reducing the mortality rate in the MES-induced seizure. Allopurinol increases the seizure threshold in PTZ-induced seizure and enhances the survival rate in MES-induced seizure. Allopurinol exerts its anti-convulsant effect, possibly through targeting NO pathway and NMDA receptors.

macrophylla root extracts in pentylenetetrazol-induced seizure models in mice

INTRODUCTION

In the present study, anticonvulsant effects of aqueous extract (AE), hydro-alcoholic crude extract (HE), and its fractions (F-CHCl3, F-EtOAc, F-MeOH) of Paeonia daurica subsp. macrophylla (P. daurica ssp. macrophylla) root examined by using a pentylenetetrazol-induced model (PTZ) on mice.

METHODS

HE and its fractions as well as AE, in concentrations of (100, 200 and 400mg/kg), valproate (Val) (100 and 200mg/kg), and saline (negative control) (10mg/kg) were injected intraperitoneally (i.p.) 30min before PTZ (80mg/kg, i.p.). The time taken before the onset of myoclonic convulsions (MC), MC duration, time taken before the onset of generalized tonic-clonic seizures (GTCS), the duration of GTCS, and the percentage of GTCS and mortality protection recorded. The plant's anticonvulsant mechanisms were assessed using flumazenil (5mg/kg, i.p.) before AE (100, 200, and 400mg/kg, i.p.) injection. GraphPad Prism software was used to compare the differences between various treatment groups with one-way analysis of variance (ANOVA) followed by Tukey-Krammer multiple comparison tests.

RESULTS

All the plant samples except F-EtOAc significantly delayed the onset and decreased the duration of PTZ-induced MCS and GTCS, and significantly reduced the GTCS and mortality rate. Pretreatment with flumazenil diminished the significant anticonvulsant effects of AE against PTZ-induced seizures.

CONCLUSIONS

It can report that extract of P. daurica ssp. macrophylla might be a helpful guide for future studies in the treatment of epilepsy.

Amomum tsaoko fruit extract exerts anticonvulsant effects through suppression of oxidative stress and neuroinflammation in a pentylenetetrazol kindling model of epilepsy in mice

BACKGROUND

Chronic epilepsy is a multifaceted common brain disorder with manifold underlying factors. Epilepsy affects around 70 million peoples worldwide. Amomum tsaoko is a perennial herbaceous plant that is extensively cultivated in many provinces of China reported to exert immense biological activities.

OBJECTIVE

This research work was aimed to reveal the therapeutic actions of ethanolic extract of A.tsaoko fruits (EE-ATF) against the pentylenetetrazol (PTZ)-provoked convulsive seizures in the mice.

METHODOLOGY

The convulsive seizures were provoked to the animals via administering 70 mg/kg of PTZ through intraperitoneally to trigger the convulsive seizures then treated with the EE-ATF at 50, 75, and 100 mg/kg orally 30 min prior to PTZ challenge. After the 30 min of PTZ challenge, animals closely monitored for signs of convulsion, generalized clonic and tonic convulsion durations, and mortality. A sub-convulsive dose 35 mg/kg of PTZ was used to provoke the kindling and seizure stages were examined using standard method. The levels of dopamine, GABA, glutamate, and Na + K + ATPase and Ca + ATPase activities in the brain tissues were studied using marker specific assay kits. The oxidative stress and antioxidant markers studied using standard methods. The mRNA expressions of COX-2, TNF-α, NF-κB, TLR-4, and IL-1β in the brain tissues were studied using RT-PCR analysis. The brain tissues were examined histologically.

RESULTS

EE-ATF treatment remarkably decreased the onset and duration of convulsion and suppressed the seizure severity and mortality in the PTZ animals. EE-ATF treatment appreciably ameliorated the PTZ triggered modifications in the GABA, glutamate, dopamine levels and Ca + 2ATPase and Na + K + ATPase activities in the brain tissues. EE-ATF suppressed the mRNA expressions of NF-κB, IL-1β, TLR-4, TNF-α, and COX-2. The status of antioxidants were elevated by the EE-ATF. Histological findings also demonstrated the curative actions of EE-ATF.

CONCLUSION

Our findings evidenced that the EE-ATF substantially ameliorated the PTZ-provoked convulsive seizures in the mice.

Effects of the Calcium Channel Blocker Otilonium Bromide on Seizure Activity in Rats With Pentylenetetrazole-Induced Convulsions

Millions of people suffer from drug-resistant epilepsy. New therapeutic approaches for removing this life-affecting disease are required. The activation of T-type calcium channels (TTCC) is one of the epileptogenesis mechanisms that cause epilepsy. So, we researched the effects of Otilonium bromide (OB), an antisposmolytic drug that inhibits TTCC, on seizure activity in rats with pentylenetetrazol (PTZ) induced convulsion. Randomly, 48 rats were divided into two groups; for electroencephalography (EEG) recordings and for behavioral assesment. Rats were treated with either intraperitoneal (IP) OB at two separate doses (25 mg/kg and 50 mg/kg) or placebo, and then pentylenetetrazole (IP), a potent seizure-inducing chemical administered to them. In our model we have measured rat seizure activity with EEG, the convulsion scala of Racine (RCS), the time of first myoclonic jerk (FMJ) and MDA levels to assess if OB has antiepileptic properties. The mean EEG spike wave percentage score reduced from 79.5% (placebo) to 59.2% (lower-dose) and 35.2% (higher-dose). FMJ had increased from a mean of 67.2 s (placebo), to 105.2 (lower-dose), 150.6 (higher-dose). RCS reduced from a mean of 5.12 (placebo) to 4.4 (lower-dose), 3.8 (higher-dose). MDA leves reduced from 84.5 nmol/gr to 51.09 nmol/gr (lower-dose), 33.2 nmol/gr (higher-dose). Compared to placebo, OB reduced significantly seizure activity at both doses, probably through blocking T-type calcium channels. All these results were statistically significant with < 0.0001 p-values. Otilonium bromide reduced seizure activity in rats with PTZ-induced convulsion. Therefore, the clinical role of OB and other TTCC inhibitors as potential anti-seizure drugs should be further investigated.

The potential antiepileptic activity of astaxanthin in epileptic rats treated with valproic acid

Objectives

Epilepsy is a neurological disease characterized by sudden, abnormal, and hyper- discharges in the central nervous system (CNS). Valproic acid (VPA) is commonly used as a broad-spectrum antiepileptic therapeutic. However, in many cases, patients develop resistance to VPA treatment due to overwhelming oxidative stress, which in turn might be a major catalyst for disease progression. Therefore, antioxidants can potentially become therapeutic agents by counteracting reactive oxygen species (ROS)-mediated damage. The present study is aimed to evaluate the potential antiepileptic effect of astaxanthin (ASTA) in pentylenetetrazol (PTZ) induced epileptic model rats that are chronically treated with VPA for 8 weeks.

Method

Fifty-male Wistar rats were randomly divided into five groups: Non-PTZ group, PTZ, PTZ/VPA, PTZ/ASTA, and PTZ/VPA/ASTA treated groups.

Results

PTZ/VPA treated group showed a neuroprotective effect with improvement in antioxidant levels, behavioral test, and histopathological changes induced by PTZ. VPA also exhibited an anti-inflammatory effect as its treatment resulted in the reduction of tumor necrosis factor-α (TNF-α). ASTA exhibited an anticonvulsant effect and enhanced anti-inflammatory effect as compared to VPA. During the combined therapy, ASTA potentiated the antiepileptic effect of the VPA by reducing the oxidative stress and TNF-α as well as increased the glutathione (GSH) levels. Also, there were substantial improvements in the behavioral and histopathological changes in the VPA/ASTA treated group as compared to the VPA treated group.

Conclusion

ASTA could have an antiepileptic and anti-inflammatory effect by reducing ROS generation. Therefore, co-administration of both the therapeutics (VPA/ASTA) has a synergistic effect in treating epilepsy and could potentially minimize recurrence and/or exacerbation of seizures.

Pentylenetetrazol-induced seizures in adult rats are associated with plastic changes to the dendritic spines on hippocampal CA1 pyramidal neurons

Epilepsy is a chronic neurobehavioral disorder whereby an imbalance between neurochemical excitation and inhibition at the synaptic level provokes seizures. Various experimental models have been used to study epilepsy, including that based on acute or chronic administration of Pentylenetetrazol (PTZ). In this study, a single PTZ dose (60 mg/kg) was administered to adult male rats and 30 min later, various neurobiological parameters were studied related to the transmission and modulation of excitatory impulses in pyramidal neurons of the hippocampal CA1 field. Rats experienced generalized seizures 1-3 min after PTZ administration, accompanied by elevated levels of Synaptophysin and Glutaminase. This response suggests presynaptic glutamate release is exacerbated to toxic levels, which eventually provokes neuronal death as witnessed by the higher levels of Caspase-3, TUNEL and GFAP. Similarly, the increase in PSD-95 suggests that viable dendritic spines are functional. Indeed, the increase in stubby and wide spines is likely related to de novo spinogenesis, and the regulation of neuronal excitability, which could represent a plastic response to the synaptic over-excitation. Furthermore, the increase in mushroom spines could be associated with the storage of cognitive information and the potentiation of thin spines until they are transformed into mushroom spines. However, the reduction in BDNF suggests that the activity of these spines would be down-regulated, may in part be responsible for the cognitive decline related to hippocampal function in patients with epilepsy.

Alpha-pinene and dizocilpine (MK-801) attenuate kindling development and astrocytosis in an experimental mouse model of epilepsy

Understanding the molecular and cellular mechanisms involved during the onset of epilepsy is crucial for elucidating the overall mechanism of epileptogenesis and therapeutic strategies. Previous studies, using a pentylenetetrazole (PTZ)-induced kindling mouse model, showed that astrocyte activation and an increase in perineuronal nets (PNNs) and extracellular matrix (ECM) molecules occurred within the hippocampus. However, the mechanisms of initiation and suppression of these changes, remain unclear. Herein, we analyzed the attenuation of astrocyte activation caused by dizocilpine (MK-801) administration, as well as the anticonvulsant effect of α-pinene on seizures and production of ECM molecules. Our results showed that MK-801 significantly reduced kindling acquisition, while α-pinene treatment prevented an increase in seizures incidences. Both MK-801 and α-pinene administration attenuated astrocyte activation by PTZ and significantly attenuated the increase in ECM molecules. Our results indicate that astrocyte activation and an increase in ECM may contribute to epileptogenesis and suggest that MK-801 and α-pinene may prevent epileptic seizures by suppressing astrocyte activation and ECM molecule production.

Perampanel exhibits anticonvulsant action against pentylentetrazol-induced seizures in immature rats

Perampanel is a new antiepileptic drug with unique mechanism of action - antagonism of AMPA receptors. Its action in immature animals is not yet sufficiently known therefore we started to study anticonvulsant action of perampanel pretreatment (1-20 mg/kg i.p.) against seizures elicited by pentylenetetrazol. Three age groups of rats were examined - 12, 18 and 25 days old. Perampanel selectively suppressed the tonic phase of generalized seizures in the two younger groups and whole tonic-clonic seizures in the 25-day-old group. It exhibited also an anticonvulsant action against minimal clonic seizures present in control 18- and 25-day-old rats. Perampanel is an effective anticonvulsant drug even at very early stages of brain development.

Intracerebroventricular administration of N-type calcium channel blocker ziconotide displays anticonvulsant, anxiolytic, and sedative effects in rats: A preclinical and pilot study

OBJECTIVE

Ziconotide (ω-conotoxin MVIIA peptide) is a novel analgesic agent acting on voltage-gated calcium channels and is administered intrathecally for neuropathic pain. While antiepileptic activities of other types of calcium channel blockers (T- or L-type) are well established, there is no information regarding the effect of ziconotide as an N-type calcium channel antagonist in pentylenetetrazol-induced seizures or its anxiolytic and sedative activities. The present study is the first to report on these effects.

METHODS

To evaluate the anticonvulsant activity of ziconotide in the pentylenetetrazol (60 mg/kg) seizure model, ziconotide was administered intracerebroventricular (i.c.v.) as a single dose (1 μg/rat) or repeatedly (chronic administration: 0.1, 0.3, or 1 μg/rat once a day for seven days). The anxiolytic and sedative actions of ziconotide were evaluated with the elevated plus maze, light/dark (LD) box, and pentobarbital-induced sleep tests. Immediately after behavioral testing, the amygdala was completely removed bilaterally to determine corticosterone levels by immunoassay.

RESULTS

In all dosing regimens, ziconotide significantly decreased the seizure frequency and also delayed the latency period compared with control. Chronic administration affected the percentage of mortality protection, while a single dose of ziconotide did not. In behavioral tests, ziconotide significantly increased both the number of entries and the percentage of time spent in the open arms of the elevated plus maze. Furthermore, ziconotide significantly increased the latency period and the number of entries into the light compartment during the LD box examination. Chronic administration of ziconotide significantly reduced the latency to sleep and increased sleeping time, whereas these parameters were not affected by a single dose. Additionally, amygdala corticosterone levels were significantly decreased in rats treated with ziconotide compared with control.

CONCLUSION

Ziconotide displays beneficial neurobehavioral effects in a model of epilepsy with anxiety as its comorbid event. It seems that at least one of the mechanisms involved in these effects is associated with a decrease in brain corticosterone levels. The main advantage of ziconotide over benzodiazepines (routine anxiolytic and sedative drugs) is that it does not cause tolerance, dependency, and addiction. Therefore, more than ever, it is necessary to improve the convenience of drug delivery protocols and attenuate the adverse effects associated with ziconotide-based therapies.

MiR-125a-5p Alleviates Dysfunction and Inflammation of Pentylenetetrazol- induced Epilepsy Through Targeting Calmodulin-dependent Protein Kinase IV (CAMK4)

BACKGROUND

MicroRNAs (miRNA) are known to play a key role in the etiology and treatment of epilepsy through controlling the expression of gene. However, miR-125a-5p in the epilepsy is little known. Epilepsy in rat models was induced by Pentylenetetrazol (PTZ) and miR- 125a-5p profiles in the hippocampus were investigated in our experiment. Also, the relationship between miR-125a-5p and calmodulin-dependent protein kinase IV (CAMK4) was identified and the related mechanism was also illustrated.

METHODS

The miR-125a-5p mRNA expression levels were evaluated by quantitative real time polymerase chain reaction (qRT-PCR). Western Blot (WB) was used to analyze the CAMK4 protein expression levels. Seizure score, latency and duration were determined based on a Racine scale. The enzyme-linked immunosorbent assay (ELISA) was used to analyze the inflammatory factor expression. The relationship between miR-125a-5p and CAMK4 was detected through dual luciferase assay.

RESULTS

Downregulation of miR-125a-5p was observed in the hippocampus of PTZ-induced epilepsy rats. The overexpression of miR-125a-5p attenuated seizure and decreased inflammatory factor level in the hippocampus of PTZ-induced rats. The miR-125a-5p alleviated epileptic seizure and inflammation in PTZ-induced rats by suppressing its target gene, CAMK4.

CONCLUSION

miR-125a-5p may represent a novel therapeutic treatment for PTZ-induced epilepsy by preventing the activation of CAMK4.

Therapeutic Effects of Oleuropein in Improving Seizure, Oxidative Stress and Cognitive Disorder in Pentylenetetrazole Kindling Model of Epilepsy in Mice

Prolonged epileptic seizures are the cause of neuronal death and brain damage. Lesions in different regions of the brain can lead to memory loss and cognitive disorders. It is therefore essential to seek out new neuroprotective drugs. Our aim was to investigate the therapeutic effects of oleuropein in improving seizure, oxidative stress, and cognitive disorder in pentylenetetrazole (PTZ) kindling model of epilepsy in mice. Mice were randomized to four groups; negative control group intraperitoneally receiving PTZ for 10 days, oleuropein group receiving oleuropein (20 mg/kg) 30 min before PTZ administration, positive control group receiving diazepam 30 min before PTZ administration and flumazenil group receiving flumazenil and then oleuropein 30 min before PTZ administration. Epilepsy severity was investigated after final administration of PTZ. Then hippocampal tissues were removed and stored at -70 °C until measurements of the interleukin-1 (IL-1) and glutamate transporter 1 (GLT-1) gene expression were conducted. Oleuropein treatment caused a significant increase in seizure latency and a significant decrease in total frequencies of head ticks, head and upper limbs seizures, the whole body seizures, frequent spinning and jumping and tonic seizures in PTZ receiving mice. IL-1 expression decreased in oleuropein group and GLT-1 levels did not change significantly in this group. Oleuropein treatment caused significant improvement of passive avoidance memory in PTZ receiving mice in shuttle box. Oleuropein can decrease PTZ-induced seizures and memory disorders due to its antioxidant and anti-inflammatory properties and is thus recommended to be used for production of anti-epileptic drugs.

Pentylenetetrazol kindling induces cortical astrocytosis and increased expression of extracellular matrix molecules in mice

Although epilepsy is one of the most common chronic neurological disorders with a prevalence of approximately 1.0 %, the underlying pathophysiology remains to be elucidated. Understanding the molecular and cellular mechanisms involved in the development of epilepsy is important for the development of appropriate therapeutic strategy. In this study, we investigated the effects of status epilepticus on astrocytes, microglia, and extracellular matrix (ECM) molecules in the somatosensory cortex and piriform cortex of mice. Activation of astrocytes was observed in many cortices except the retrosplenial granular cortex after pentylenetetrazol (PTZ)-induced kindling in mice. Activated astrocytes in the cortex were found in layers 1-3 but not in layers 4-6. In the somatosensory and piriform cortices, no change was observed in the number of parvalbumin (PV)-positive neurons and PV-positive neurons covered with perineuronal nets. However, the amount of ECM in the extracellular space increased. The expression of VGLUT1- and GAD67-positive synapses also increased. Thus, in the PTZ-kindling epilepsy mice model, an increase in the number of ECM molecules and activation of astrocytes were observed in the somatosensory cortex and piriform cortex. These results indicate that PTZ-induced seizures affect not only the hippocampus but also other cortical areas. Our study findings may help to develop new therapeutic approaches to prevent seizures or their sequelae.

Clavulanic acid improves ethanol withdrawal symptoms in rats

Objective(s):

Ethanol withdrawal following chronic use, is an important challenge clinically. In this study, the effect of clavulanic acid was evaluated on the symptoms of ethanol withdrawal in rats.

Materials and Methods:

Alcohol dependence was induced by the gavage of ethanol (10% v/v, 2 g/kg), twice daily for 10 days. Clavulanic acid (10, 20, 40, and 80 mg/kg) was administered concurrently with ethanol (sub-acute study), or a single dose after ethanol withdrawal (acute study). Six hours after the last dose of ethanol, anxiety was assessed by the elevated plus-maze (EPM). Seizure-like behavior was evaluated by a sub-convulsive dose of pentylenetetrazol (PTZ, 25 mg/kg/IP). Locomotor activity and motor coordination were measured by the open field and rotarod tests, respectively. Lipid peroxidation marker and antioxidant content were assessed through measuring malondialdehyde (MDA) and glutathione (GSH), respectively.

Results:

The number of entries and time spent on the open arms of EPM decreased during the withdrawal state. Motor coordination and locomotor activity were significantly decreased. In the sub-acute study, clavulanic acid 80 mg/kg increased time spent and the number of entries to the open arms of EPM, in withdrawn animals. Both motor incoordination and locomotor activity reduction were normalized by clavulanic acid (10, 20, 40 and 80 mg/kg). Withdrawal-induced PTZ kindling seizure was also suppressed by all of the doses. MDA increased, while GSH decreased after withdrawal. Clavulanic acid attenuated such changes.

Conclusion:

Clavulanic acid could prevent the development of alcohol withdrawal-induced anxiety and seizure. Alcohol withdrawal causes oxidative stress which can be prevented by clavulanic acid.

The Protective Effect of Auraptene Against Oxidative Stress and Pentylenetetrazol-Induced Chemical Kindling in Mice

It is believed that some pitfalls in the treatment of epilepsy such as serious side effects of medications and drug resistance may be resolved by natural compounds. Auraptene belongs to coumarins and is found in citrus peel. We hypothesized that auraptene might have anticonvulsant properties. Kindling was induced by repeated intraperitoneal (IP) injections of pentylenetetrazol (PTZ, 35 mg/kg) with two-day intervals for 24 days in male albino mice. Three groups received IP injections of auraptene (12.5, 25, and 50 mg/kg). Three control groups received vehicle, diazepam (3 mg/kg, IP), and vitamin E (150 mg/kg, IP). Seizure-related behaviors were recorded for 30 min after PTZ injection. Moreover, malondialdehyde and reduced glutathione (GSH) were measured in the brain. The results indicated that auraptene at the dose of 12.5 mg/kg and vitamin E significantly prolonged the latency to stage 2 of seizures (P < 0.01). Auraptene at the doses of 25 mg/kg and 50 mg/kg, prolonged the latency to stage 4 (P < 0.01) and reduced stage 5 duration of seizures (P < 0.01). All doses of auraptene reduced median of seizure scores (P < 0.01). The kindled control group had MDA levels similar to intact animals but had a lower concentration of GSH (P < 0.001). None of the tested compounds changed the malondialdehyde concentration significantly. However, auraptene at the dose of 50 mg/kg and vitamin E increased GSH levels (P < 0.05). The results suggest that auraptene had anticonvulsant effects in PTZ-induced chemical kindling that was mediated by mechanisms other than the antioxidant effect of auraptene.

Capsaicin Exerts Anti-convulsant and Neuroprotective Effects in Pentylenetetrazole-Induced Seizures

The transient receptor potential vanilloid-1 (TRPV1) receptor has been implicated in the development of epileptic seizures. We examined the effect of the TRPV1 agonist capsaicin on epileptic seizures, neuronal injury and oxidative stress in a model of status epilepticus induced in the rat by intraperitoneal (i.p.) injections of pentylenetetrazole (PTZ). Capsaicin was i.p. given at 1 or 2 mg/kg, 30 min before the first PTZ injection. Other groups were i.p. treated with the vehicle or the anti-epileptic drug phenytoin (30 mg/kg) alone or co-administered with capsaicin at 2 mg/kg. Brain levels of malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide, and paraoxonase-1 (PON-1) activity, seizure scores, latency time and PTZ dose required to reach status epilepticus were determined. Histopathological assessment of neuronal damage was done. Results showed that brain MDA decreased by treatment with capsaicin, phenytoin or capsaicin/phenytoin. Nitric oxide decreased by capsaicin or capsaicin/phenytoin. GSH and PON-1 activity increased after capsaicin, phenytoin or capsaicin/phenytoin. Mean total seizure score decreased by 48.8% and 66.3% by capsaicin compared with 78.7% for phenytoin and 69.8% for capsaicin/phenytoin treatment. Only phenytoin increased the latency (115.7%) and threshold dose of PTZ (78.3%). Capsaicin did not decrease the anti-convulsive effect of phenytoin but prevented the phenytoin-induced increase in latency time and threshold dose. Neuronal damage decreased by phenytoin or capsaicin at 2 mg/kg but almost completely prevented by capsaicin/phenytoin. Thus in this model of status epilepticus, capsaicin decreased brain oxidative stress, the severity of seizures and neuronal injury and its co-administration with phenytoin afforded neuronal protection.

Effect of acute pentylenetetrazol injection induced epileptic seizures on rat dentate gyrus at different postnatal ages

Epilepsy is one of the most common neurological disorders, its prevalence approximately from 0.5% to 2% of the general population. Generalized seizures could lead to several morphological changes in the brain. This study aimed to investigate the morphological effects of a single convulsive dose of pentylenetetrazol (PTZ) on rat dentate gyrus at different postnatal ages. Thirty-six male Wistar rats were used at the following postnatal ages: P10, P21, and P90 (12 rats per each age). The animals in each age were equally divided into two groups: group I, control and group II, treated with a single intraperitoneal injection of PTZ (55 mg/kg). After confirmation of generalized tonic-clonic seizures, specimens from the right dentate gyrus were processed for light and electron microscopy. In PTZ-treated groups, the number of granule cells significantly decreased. Dark granule cells appeared in the deep layers of the granule cells in P10 and with the progress of age, they significantly increased in number and extended into the superficial layers of the granule cells. The dendritic spines diminished. Glial fibrillary acidic protein and caspase-3 expression increased. Ultrastructurally, granule cells showed irregular shaped nucleus, dilated rough endoplasmic reticulum (RER) cisternae, mitochondria with damaged cristae, large vacuoles, lysosomes, and lipofuscin granules. Dark granule cells characterized by electron-dense nucleus and cytoplasm containing disorganized Golgi bodies, swollen mitochondria with damaged cristae, numerous free ribosomes and few long strands of RER. Astrocytes had hypertrophied cell body. Acute treatment with PTZ-induced epileptic seizures caused toxic effect on the structure of rat dentate gyrus at different postnatal ages.

Effect of rutin on anxiety-like behavior and activity of acetylcholinesterase isoforms in specific brain regions of pentylenetetrazol-treated mice

The aim of the present study was to investigate the effect of rutin administration (100 mg/kg/day) to pentylenetetrazol (PTZ)-treated Balb-c mice (60 mg/kg/day), with respect to anxiety-like behavior using both open-field and elevated plus-maze (EPM) tests, and acetylcholinesterase (AChE) activity in salt-soluble (SS) fraction and detergent-soluble (DS) fraction of the cerebral cortex, hippocampus, striatum, midbrain, and diencephalon. Our results demonstrated that the administration of PTZ in 3 doses and the induction of seizures increased significantly anxiety behavior of mice and reduced significantly DS-AChE activity in all brain regions examined, while the reduction in the SS fraction was brain region-specific. Rutin administration to normal mice did not affect their behavior, while it induced a brain region-specific reduction in SS-AChE and a significant decrease in DS-AChE in all brain regions. We demonstrated for the first time that pretreatment of PTZ-mice with rutin (PTZ + Rutin group) prevented the manifestation of anxiety and induced interestingly a further significant reduction on the SS- and DS-AChE activities only in the cerebral cortex and striatum, in comparison with PTZ group. Our results show that rutin exhibits an important anxiolytic effect and an anticholinesterase activity in specific brain areas in the seizure model of PTZ.

Interaction of GABAA and GABAB antagonists after status epilepticus in immature rats

Among neurotransmitter systems affected by status epilepticus (SE) in adult rats are both GABAergic systems. To analyze possible changes of GABA_A and GABA_B systems in developing rats lithium-pilocarpine SE was induced at postnatal day 12 (P12). Seizures were elicited by a GABA_A antagonist pentylenetetrazol (PTZ) 3, 6, 9, and 13 days after SE (i.e., in P15, P18, P21, and P25 rats), and their possible potentiation by a GABA_B receptor antagonist CGP46381 was studied. Pilocarpine was replaced by saline in control animals (lithium-paraldehyde [LiPAR]). Pentylenetetrazol in a dose of 50 mg/kg s.c. elicited generalized seizures in nearly all 15-day-old naive rats and in 40% of 18-day-old ones but not in older animals. After SE, PTZ no longer elicited seizures in these two younger groups, i.e., sensitivity of GABA_A system was diminished. The GABA_B antagonist exhibited proconvulsant effect in P15 and P18 SE as well as LiPAR rats returning the incidence of PTZ-induced seizures to values of control animals. A decrease in the incidence of minimal clonic seizures was seen in P21 LiPAR animals; these seizures in the oldest group were not affected. Change of the effect from proconvulsant to anticonvulsant (or at least to no action) took place before postnatal day 21. Both SE and LiPAR animals exhibited similar changes but their intensity differed, effects in LiPAR controls were usually more expressed than in SE rats.

Mild foot electrical stimulation is comparable with phenytoin in inhibiting pentylenetetrazol-induced kindling in rats

Increasing evidence demonstrates that electric stimulation has anticonvulsant effects. The present study was undertaken to investigate the effects of mild foot electrical stimulation (MFES) on the development of pentylenetetrazol (PTZ) kindling and compare its effectiveness with the more commonly used treatment, phenytoin. Kindling was induced in rats by repeated injections (every 24 h) of PTZ (37.5 mg/kg). The rats were subjected to either MFES (0.2 mA in intensity for a 160 ms duration with a 160 ms interval for 20 min) or phenytoin (30 mg/kg) before PTZ injections. Following this treatment, rats received MFES every other day for 10 days or 26 days after establishment of PTZ kindling. The data showed that MFES significantly inhibited development of chemical kindling induced by PTZ in rats (p = 0.001, as compared to PTZ-treated animals). This inhibitory effect is comparable with the effect of 30 mg/kg doses of phenytoin (P = 0.99, as compared to phenytoin group). However, 10 days or 26 days durations of MFES had no effect on established kindled seizures (P = 0.58 as compared to PTZ-treated animals). Our data demonstrate that although MFES significantly inhibited the development of chemical kindling, this experimental paradigm had no effect on established kindled seizures.

Status Epilepticus Increases Cell Proliferation and Neurogenesis in the Developing Rat Cerebellum

Status epilepticus (SE) promotes neuronal proliferation and differentiation in the adult and developing rodent hippocampus. However, the effect of SE on other neurogenic brain regions such as the cerebellum has been less explored. To determine whether SE induced by pentylentetrazole (PTZ-SE) and lithium-pilocarpine (Li-Pilo-SE) increases cell proliferation and neurogenesis in the developing rat cerebellum. SE was induced in 14-day-old (P14) Wistar rat pups (both sexes). One hour after SE and the following day rats were injected intraperitoneally with 5-bromo-2'-deoxyuridine (BrdU, 50 mg/kg). Seven days after SE, immunohistochemistry was performed to detect BrdU-positive (BrdU+) cells or BrdU/NeuN+ cells in the cerebellar vermis. SE induced by PTZ or Li-Pilo statistically significant increased the number of cerebellar BrdU+ cells when compared with the control group (58% and 40%, respectively); maximal cell proliferation occurred in lobules II, III, VIb, VIc, VIII, IXa, and IXb of PTZ-SE group and II, V, VIc, VII, and X of Li-Pilo-SE group. An increased number of BrdU/NeuN+ cells was detected in lobules V (17 ± 1.9), VIc (25.8 ± 2.7), and VII (26.2 ± 3.4) after Li-Pilo-SE compared to their control group (9.8 ± 1.7, 12.8 ± 2.8, and 11 ± 1.7, respectively), while the number of BrdU/NeuN+ cells remained the same after PTZ-induced SE or control conditions. SE induced in the developing rat by different experimental models increases cell proliferation in the granular layer of the cerebellar vermis, but only SE of limbic seizures increases neurogenesis in specific cerebellar lobes.

Propionate relieves pentylenetetrazol-induced seizures, consequent mitochondrial disruption, neuron necrosis and neurological deficits in mice

The present research was designed to evaluate the protective effects and underlying mechanisms of propionate, a bioactive food additive, on mitochondrial disruption, neuron necrosis and neurological deficits after epilepsy seizures. Epilepsy seizures was induced by repetitive injections of pentylenetetrazol at a dose of 37 mg per kg. Propionate (37.5, 50 and 75 mg/kg) as well as sodium valproate (300 mg/kg) were administrated intragastrically (i.g.) 1 h before each PTZ injection and continued for 40 days. The influence of propionate was assessed by many biochemical assays and neurobehavioral experiments. The results of gas chromatography (GC) analysis indicated that increased concentration of propionate can be explored in hippocampus area of propionate + PTZ treated animals. Propionate decreased epilepsy seizure intensity, increased latency of seizures. Meanwhile, propionate treatment reversed the structure disruption of the mitochondria, improved ATP level and lessened 8-OHdG level in the brains of animals with seizures. In addition, we find propionate pretreated can increase activities of the antioxidant enzymes (CAT, SOD, as well as GSH-Px) in mitochondria. Additionally, propionate reduced neuronal loss in hippocampus and our results suggest that HIF-1α/ERK pathway and neuron necrosis exists potential linkage during epileptogenesis. Moreover, as a result, propionate administration can significantly improve the neurological function estimated by a battery of functional tests. In conclusion, treatment with propionate attenuates mitochondrial disruption, hippocampal apoptosis and neurological deficits in a mouse model of epilepsy seizures. Therefore, propionate, currently used as a food preservative, has a potential additional advantage of ameliorating epilepsy seizures.

Validated animal models for antiseizure drug (ASD) discovery: Advantages and potential pitfalls in ASD screening

Since 1993, over 20 new anti-seizure drugs (ASDs) have been identified in well-established animal seizure and epilepsy models and subsequently demonstrated to be clinically effective in double-blinded, placebo-controlled clinical trials in patients with focal onset seizures. All clinically-available ASDs on the market today are effective in at least one of only three preclinical seizure and epilepsy models: the acute maximal electroshock (MES), the acute subcutaneous pentylenetetrazol (scPTZ) test, or the kindled rodent with chronic evoked seizures. Thus, it reasons that preclinical ASD discovery does not need significant revision to successfully identify ASDs for the symptomatic treatment of epilepsy. Unfortunately, a significant need still persists for more efficacious and better tolerated ASDs. This is particularly true for those patients whose seizures remain drug resistant. This review will focus on the continued utility of the acute MES and scPTZ tests, as well as the kindled rodent for current and future ASD discovery. These are the only "clinically validated" rodent models to date and been heavily used in the search for novel and more efficacious ASDs. This is to say that promising ASDs have been brought to the clinic on the basis of efficacy in these particular seizure and epilepsy models alone. This review also discusses some of the inherent advantages and limitations of these models relative to existing and emerging preclinical models. It then offers insight into future efforts to develop a preclinical model that will advance a truly transformative therapy for the symptomatic treatment of difficult to treat focal onset epilepsy. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

MPMT-OX up-regulates GABAergic transmission and protects against seizure-like behavior in Caenorhabditis elegans

The signal transmission in the nervous system operates through a sensitive balance between excitatory (E) inputs and inhibitory (I) responses. Imbalances in this system contribute to the development of pathologies such as seizures. In Caenorhabditis elegans, the locomotor circuit operates via the coordinated activity of cholinergic excitatory (E) and GABAergic inhibitory (I) transmission. Changes in E/I inputs can cause uncontrolled electrical discharges, mimicking the physiology of seizures. Molecules derived from 1,3,4-oxadiazole have been found to exhibit diverse biological activities, including anticonvulsant effect. In this work, we study the activity of the compound 2-[(4-methoxyphenylselenyl)methylthio]-5-phenyl-1,3,4-oxadiazole (MPMT-OX) in the GABAergic and cholinergic systems. We demonstrate that MPMT-OX reduced the locomotor activity of C. elegans with a normal balance between the E/I systems and increased the resistance to paralysis in worms exposed to pentylenetetrazol and aldicarb. MPMT-OX increased seizure resistance and assisted in the recovery of locomotor activity in worms with deletions in the genes unc-46, which regulates the transport of GABA into vesicles, and unc-49, which encodes the GABA_A receptor. C. elegans with deletions in the unc-25 and unc-47 genes did not respond to treatment. Therefore, we suggest that the compound MPMT-OX upregulates GABAergic signaling in a manner dependent on the unc-25 gene, which is responsible for GABA synthesis, and unc-47, which encodes the vesicular GABA transporter.

The anticonvulsant and neuroprotective effects of kir2.3 activation in PTZ-induced seizures and the kainic acid model of TLE

PURPOSE

To elucidate the role of activating the inwardly rectifying K⁺ channel 2.3 (Kir2.3) in acute seizure and chronic epilepsy, we investigated the effect of a Kir2.3 agonist (tenidap) on epileptic and electrophysiological activities in mice. Neuronal excitability and damage were also evaluated.

METHODS

A Pentylenetetrazole (PTZ)-induced acute seizure model and a kainic acid (KA)-induced temporal epilepsy model were used in adult mice. The mice were given tenidap 30 min before PTZ injection or were given tenidap for 7 days after entering the chronic stage of the KA model. Video monitoring and EEG recordings were performed for comparisons. Immunofluorescence of c-fos was detected in the PTZ model, and Nissl staining was performed in the KA model.

RESULTS

Tenidap intervention significantly reduced the duration and severity of PTZ-induced acute seizures, which conformed with the power-spectrum analyses of the EEG and the quantification of spikes on EEG. C-fos expression representing neuronal excitability was also reduced with tenidap pretreatment. However, the latency time to seizure onset was unaltered. Seven days of tenidap treatment in the chronic KA model significantly attenuated seizure and spike frequencies compared to the same animal before administration. Nissl staining showed reduced hilar neuron loss in the tenidap-intervention group but showed no difference in the width of the granule cell layer.

CONCLUSION

To our knowledge, few studies have reported the relevance of Kir2.3 to epilepsy. The present data suggested that activation of Kir2.3 exerts an anticonvulsant effect in acute seizures and the chronic stage of TLE, which makes this channel a potent therapeutic target.

Early α-linolenic acid exposure to embryo reduces pentylenetetrazol-induced seizures in zebrafish larva

Over the past few years, there has been a tremendous increase in interest of general population toward food-based therapies for management of chronic clinical conditions due to their lesser adverse effects with prolonged use over pharmacotherapies. Foods enriched with omega-3 fatty acids have shown some promising results in case of epilepsy. The present study was envisioned to investigate the effect of early exposure of α-linolenic acid (ALA), an essential omega-3 fatty acid in developing zebrafish (Danio rerio) embryos toward pentylenetetrazol (PTZ)-induced seizure susceptibility. The healthy wild-type zebrafish embryos were incubated in system water or system water containing different ALA concentrations (1-20 µM) till 7 dpf (days post fertilization). Each larva at 7 dpf was placed in 8 mM PTZ solution and seizure event was recorded. ALA incubation at 10 µM and 20 µM concentrations showed a dose-dependent reduction in PTZ-mediated hyperactive responses in larvae indicated by a marked decrease in total distance travelled and speed, as compared to vehicle control. Furthermore, both the treated groups showed increase in the latency to PTZ-induced clonus-like seizures in larvae, as compared to vehicle control. ALA incubated larvae at 10 µM and 20 µM concentrations also showed a significant reduction in c-fos mRNA level. A marked increase in the level of ALA and docosahexaenoic acid was also observed in the larvae incubated at highest effective concentration of ALA. The present study concluded that embryonic exposure of ALA reduced PTZ-induced seizures in zebrafish larva.

Deficiency of urokinase-type plasminogen activator and its receptor affects social behavior and increases seizure susceptibility

Extracellular proteolysis initiated by the binding of urokinase-type plasminogen activator (uPA) to its receptor (uPAR) regulates the development of inhibitory neuronal circuits in the cerebral cortex and tissue remodeling after epileptogenic brain injury. To study the function of different components of the uPA-uPAR system on behavior and epileptogenesis, and to complement our previous studies on naïve and injured mice deficient in the uPA-encoding gene Plau or the uPAR-encoding gene Plaur, we analyzed the behavioral phenotype, seizure susceptibility, and perineuronal nets surrounding parvalbumin-positive inhibitory interneurons in Plau and Plaur (double knockout dKO) mice. In a climbing test, dKO mice showed reduced interest towards the environment as compared with Wt mice (p < 0.01). In a social approach test, however, dKO mice spent more time than Wt mice exploring the compartment containing a stranger mouse than the empty compartment (p < 0.05). Moreover, in a social interaction test, dKO mice exhibited increased contact time (p < 0.01). Compared with Wt mice, the dKO mice also had a longer single contact duration (p < 0.001) with the stranger mouse. In the elevated plus-maze, grooming, and marble burying tests, the anxiety level of dKO mice did not differ from that of Wt mice. Rearing time in an exploratory activity test, and spatial learning and memory in the Morris swim navigation task were also comparable between dKO and Wt mice. In the pentylenetetrazol (PTZ) seizure-susceptibility test, dKO mice had a shorter latency to the first epileptiform spike (p = 0.0001) and a greater total number of spikes (p < 0.001) than Wt mice. The dKO genotype did not affect the number of cortical perineuronal nets. Our findings indicate that Plau/Plaur-deficiency leads to a more social phenotype toward other mice with diminished interest in the surrounding environment, and increased seizure susceptibility.

Myristica Fragrans Houtt Extract Attenuates Neuronal Loss and Glial Activation in Pentylenetetrazol-Induced Kindling Model

Inflammatory reactions are closely associated with the development and progression of epilepsy. It has been shown that inhibition of pro-inflammatory cytokines, which are released from activated astrocytes and microglia, are considered to be an effective therapeutic approach for the treatment of epileptic disorders. Regarding the anti-inflammatory effects of nutmeg (Myristica fragrans Houtt), the present study was designed to investigate whether the nutmeg ethanolic extract could exert anticonvulsant and inhibitory effects on glial activation in pentylenetetrazol (PTZ)-induced mice model of kindling. Ethanolic extract of nutmeg was administrated intraperitoneally (i.p.) 1 hour before PTZ injection or one week before PTZ as a separate group, to become fully-kindled. The chemical components of nutmeg extract were analyzed by gas chromatography mass spectrometry (GC-MS). Immunostaining against neuronal and glial markers was performed on hippocampus sections. GC-MS data indicated that the main components of nutmeg extract are myristic acid (39.93%), elemicin (22.16%) and myristicin (11.17%). Behavioral studies showed that pre-treatment of nutmeg extract effectively reduced seizures behavior, decreased cell death, and ameliorated glial activation that is followed by PTZ administration. In conclusion, nutmeg extract might be regarded as a useful supplementary agent in epilepsy treatment through its attenuation of neuronal loss and glial activation.

Levodropropizine suppresses seizure activity in rats with pentylenetetrazol-induced epilepsy

BACKGROUND

Millions of individuals worldwide suffer from epilepsy, and up to 25% of patients have seizures that are resistant to currently available antiepileptic drugs. Hence, there continues to be a need for more seizure medications that are effective yet tolerable. Levodropropizine (LVDP) is an established antitussive drug that, based on preclinical data, may also have antiepileptic activity.

METHODS

We treated rats with either intraperitoneal (IP) LVDP at two different doses or placebo in randomized fashion and then exposed them to IP pentylenetetrazol (PTZ), a potent seizure-inducing compound. We measured the rats' subsequent seizure activity with electroencephalography (EEG), Racine's convulsion scale (RCS) and time to first myoclonic jerk (TFMJ) to determine whether LVDP has antiepileptic properties in our murine model for epilepsy.

RESULTS

When compared to placebo, LVDP at both doses significantly suppressed seizure activity. Mean EEG spike wave percentage score decreased from 76.8% (placebo) to 13.1% (lower dose) and 7.6% (higher dose, bothp <  0.0001). RCS decreased from a mean of 5.8 (placebo) to 1.83 (lower dose) and 1.16 (higher dose, both p <  0.05). TFMJ had increased from a mean of 65.1 s (placebo), to 247.3 s (lower dose) and 295.5 s (higher dose, both p <  0.0001).

CONCLUSIONS

Levodropropizine, a common antitussive drug, suppresses seizure activity in rats with PTZ-induced status epilepticus. Given the ongoing need to find effective therapies for refractory epilepsy, the possibility of using levodropropizine as an antiepilepticshould be further explored.

Carvacrol mitigates proconvulsive effects of lipopolysaccharide, possibly through the hippocampal cyclooxygenase-2 inhibition

Systemic injection of LPS changes neuronal excitability and increase susceptibility for convulsions. Carvacrol exerts neuroprotective and antiepileptic effects in animal models. Herein, we investigated the anticonvulsive effect of carvacrol on LPS induced seizure severity and possible involvement of the hippocampal COX-1 and -2 activities in this effect. Adult male wistar rats were used. LPS was injected (400 μg/kg; i.p.) four hours before the PTZ (80 mg/kg; i.p.) injection. Carvacrol was injected (100 mg/kg; i.p.) immediately after the LPS injection. Following the PTZ injection, behavioral seizures were observed for 30 min. Latency and duration for each stage were recorded for analysis. Rats divided into seven groups: (1) PTZ, (2) LPS + PTZ, (3) carvacrol + PTZ, (4) LPS + carvacrol + PTZ, (5) LPS, (6) carvacrol, (7) intact. At the end of the experimental procedure the hippocampus of all animals were extracted to measure COX- 1 and 2 levels using the ELISA. LPS injection four hours before the PTZ injection were significantly reduced latency to seizure stages 3-5 and increased duration of the stage 5 in compare with PTZ group (p < 0.05). Carvacrol significantly reduced these effects of LPS on seizure susceptibility (p < 0.05). However, injection of carvacrol alone before the PTZ injection did not significantly affect seizure indexes in compare with PTZ group. Additionally, LPS significantly increased hippocampal level COX-2 but not COX-1 (p < 0.01) and carvacrol significantly attenuates this effect of LPS (p < 0.001). Carvacrol prevents the proconvulsant effect of LPS possibly through the inhibition of the COX-2 increased activity.

Changing effect of GABA B receptor antagonist CGP46381 after status epilepticus in immature rats

Possible proconvulsant action of GABA_B receptor antagonist CGP46381 was studied 3 and 13 days after status epilepticus elicited in 12-day-old rats. GABAA-dependent activity was tested by pentylenetetrazol administration and found different in 15-day-old rats after status epiolepticus but not in the older group. The interaction of the two GABAergic systems should be studied in detail.

The role of serotonin and its receptors on the anticonvulsant effect of curcumin in pentylenetetrazol-induced seizures

AIM

Curcumin, derived from turmeric, has been demonstrated to be effective in controlling seizures, although the exact mechanism is yet unknown. In this study, the role of serotonin and its receptors in the anticonvulsant effect of curcumin was evaluated in mice.

MAIN METHODS

Total 110 mice were randomly divided into 11 groups (n = 10). In the first to the fourth groups, the role of curcumin (150 mg/kg, i.p) and serotonin (PCPA (100 mg/kg); was used to deplete the brain serotonin levels) was investigated. The fifth group first received NAD-299 (4 mg/kg, sc), RS-102221 (5 mg/kg, i.p), SDZ205-557 Hydrochloride (1 mg/kg, i.p), and SB 26997 (10 mg/kg, i.p), then curcumin. The sixth group received NAD-299, curcumin. The animals in the seventh to ninth groups received 5-HT2C, 5-HT4, and 5-HT7 antagonists, respectively, with curcumin. The tenth group received HTR2C antagonist and the eleventh group received HTR4 antagonist. In all animals 25 min after curcumin PTZ (80 mg/kg; i.p) was injected.

KEY FINDINGS

PCPA not only inhibited the anticonvulsant action of curcumin, but also reversed some of its anticonvulsant effect. The 5-HT1A, 5-HT2C and 5-HT4 antagonists diminished but 5-HT7 antagonist strengthened the anticonvulsant effect of curcumin. Evaluation of gene expression using real-time PCR confirmed that only 5-HT7 gene expression was reduced after curcumin injection.

SIGNIFICANCE

According to these results, it may be suggested that curcumin exerts anticonvulsive effects by increasing the serotonin levels in the brain that influence receptors, including 5-HT1A, 5-HT2C, and 5-HT4 and likely through the reduction of 5-HT7 gene expression.

A Caenorhabditis elegans assay of seizure-like activity optimised for identifying antiepileptic drugs and their mechanisms of action

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Worms with mutant GABA_A receptors exhibit convulsions upon exposure to pentylenetetrazol.

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Convulsions are prevented by the approved anti-epileptic drug, ethosuximide.

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C. elegans model is a higher throughput, ethical alternative to rodent seizure models.

Background

Epilepsy affects around 1% of people, but existing antiepileptic drugs (AEDs) only offer symptomatic relief and are ineffective in approximately 30% of patients. Hence, new AEDs are sorely needed. However, a major bottleneck is the low-throughput nature of early-stage AED screens in conventional rodent models. This process could potentially be expedited by using simpler invertebrate systems, such as the nematode Caenorhabditis elegans.

New method

Head-bobbing convulsions were previously reported to be inducible by pentylenetetrazol (PTZ) in C. elegans with loss-of-function mutations in unc-49, which encodes a GABA_A receptor. Given that epilepsy-linked mutations in human GABA_A receptors are well documented, this could represent a clinically-relevant system for early-stage AED screens. However, the original agar plate-based assay is unsuited to large-scale screening and has not been validated for identifying AEDs. Therefore, we established an alternative streamlined, higher-throughput approach whereby mutants were treated with PTZ and AEDs via liquid-based incubation.

Results

Convulsions induced within minutes of PTZ exposure in unc-49 mutants were strongly inhibited by the established AED ethosuximide. This protective activity was independent of ethosuximide’s suggested target, the T-type calcium channel, as a null mutation in the worm cca-1 ortholog did not affect ethosuximide’s anticonvulsant action.

Comparison with existing method

Our streamlined assay is AED-validated, feasible for higher throughput compound screens, and can facilitate insights into AED mechanisms of action.

Conclusions

Based on an epilepsy-associated genetic background, this C. elegans unc-49 model of seizure-like activity presents an ethical, higher throughput alternative to conventional rodent seizure models for initial AED screens.

Upregulation of klotho and erythropoietin contributes to the neuroprotection induced by curcumin-loaded nanoparticles in experimental model of chronic epilepsy

Klotho, which is a life extension factor, and erythropoietin (EPO) have been introduced as effective neuroprotective factors in several neurological disorders. The present study is an attempt to examine the potential role of klotho and EPO in therapeutic effect of curcumin-loaded nanoparticles (NPs) in pentylenetetrazol (PTZ)-induced kindling model. In order to induce the kindling model, PTZ was administrated intraperitoneally (i.p.) at dose of 36.5 mg/kg every other day for 20 days. Male NMRI mice received pre-treatment of free curcumin or curcumin-loaded NPs (12.5 mg/kg, i.p.) 10 days before PTZ injection and this was continued until 1 h before each PTZ injection. Immunostaining against NeuN, as a marker of neuronal maturation, and EPO was performed on hippocampal brain sections. Quantitative real time polymerase chain reaction (qRT-PCR) was conducted to assess the expression levels of tumor necrosis factor-α (TNF-α), klotho and EPO in the hippocampus. Immunostaining data indicated that treatment with curcumin-loaded NPs significantly alleviates the neuronal cell death in PTZ receiving animals. Curcumin-loaded NPs effectively upregulated the levels of EPO and klotho in PTZ receiving animals. Furthermore, mRNA level of TNF-α was considerably reduced in animals undergone curcumin-loaded NPs treatment. Overall, the results of this study suggest that downregulation of TNF-α and consequent upregulation of klotho and EPO might contribute to the neuroprotective effect of curcumin-loaded NPs in experimental model of epilepsy.

Highly selective SGLT2 inhibitor dapagliflozin reduces seizure activity in pentylenetetrazol-induced murine model of epilepsy

Background

Worldwide, over 10 million individuals suffer from drug-resistant epilepsy. New therapeutic strategies are needed to address this debilitating disease. Inhibition of sodium-glucose linked transporters (SGLTs), which are variably expressed in the brain, has been demonstrated to reduce seizure activity in murine models of epilepsy. Here we investigated the effects of dapagliflozin, a highly competitive SGLT2 inhibitor currently used as a drug for diabetes mellitus, on seizure activity in rats with pentylenetetrazol (PTZ) induced seizures.

Methods

Laboratory rats (n = 48) were evenly randomized into two experiments, each with four study arms: (1) a vehicle-treated (placebo) arm infused with saline; (2) a control arm infused with PTZ; (3) a treatment arm with PTZ and dapagliflozin at 75 mg/kg, and (4) another treatment arm with PTZ and dapagliflozin at 150 mg/kg. Study subjects were assessed for seizures either via EEG as measured by spike wave percentage (SWP), or clinically via Racine’s scales scores (RSS) and time to first myoclonic jerk (TFMJ).

Results

Rats treated with dapagliflozin had lower mean SWP on EEG (20.4% versus 75.3% for untreated rats). Behaviorally, treatment with dapagliflozin improved means RSS (2.33 versus 5.5) and mean TFMJ (68.3 versus 196.7 s). All of these findings were statistically significant with p-values of < 0.0001. There was a trend towards even better seizure control with the higher dose of dapagliflozin at 150 mg/kg, however this was not consistently statistically significant.

Conclusions

Dapagliflozin decreased seizure activity in rats with PTZ–induced seizures. This may be explained by the anti-seizure effects of decreased glucose availability and a reduction in sodium transport across neuronal membranes which can confer a stabilizing effect against excitability and unwanted depolarization. The potential clinical role of dapagliflozin and other SGLT2 inhibitors as anti-seizure medications should be further explored.

Curcumin-loaded chitosan-alginate-STPP nanoparticles ameliorate memory deficits and reduce glial activation in pentylenetetrazol-induced kindling model of epilepsy

Despite several beneficial effects of curcumin, its medical application has been hampered due to low water solubility. To improve the aqueous solubility of curcumin, it has been loaded on chitosan (CS)-alginate (ALG) - sodium tripolyphosphate (STPP) nanoparticles (NPs). Then, the effect of curcumin NPs on memory improvement and glial activation was investigated in pentylenetetrazol (PTZ)-induced kindling model. Male NMRI mice have received the daily injection of curcumin NPs at dose of 12.5 or 25mg/kg. All interventions were injected intraperitoneally (i.p), 10days before PTZ administration and the injections were continued until 1h before each PTZ injection. Spatial learning and memory was evaluated using Morris water maze test after the 7th PTZ injection. Animals have received 10 injections of PTZ and then, brain tissues were removed for histological evaluation. Nissl staining was used to determine the level of cell death in hippocampus and immunostaining method was performed against NeuN and GFAP/Iba1 for assessment of neuronal density and glial activation respectively. Behavioral results showed that curcumin NPs exhibit anticonvulsant activity and prevent cognitive impairment in fully kindled animals. The level of cell death and glial activation reduced in animals which have received curcumin NPs compared to those received free curcumin. To conclude, these findings suggest that curcumin NPs effectively ameliorate memory impairment and attenuate the level of activated glial cells in a mice model of chronic epilepsy.

Pentylenetetrazol modulates redox system by inducing addicsin translocation from endoplasmic reticulum to plasma membrane in NG108-15 cells

Addicsin (Arl6ip5) is a multifunctional physiological and pathophysiological regulator that exerts its effects by readily forming homo- and hetero-complexes with various functional factors. In particular, addicsin acts as a negative modulator of neural glutamate transporter excitatory amino acid carrier 1 (EAAC1) and participates in the regulation of intracellular glutathione (GSH) content by negatively modulating EAAC1-mediated cysteine and glutamate uptake. Addicsin is considered to play a crucial role in the onset of neurodegenerative diseases including epilepsy. However, the molecular dynamics of addicsin remains largely unknown. Here, we report the dynamics of addicsin in NG108-15 cells upon exposure to pentylenetetrazol (PTZ), a representative epileptogenic agent acting on the gamma-Aminobutyric acid A (GABA_A) receptor. Fluorescent immunostaining analysis demonstrated that addicsin drastically changed its localization from the endoplasmic reticulum (ER) to the plasma membrane within 1 h of PTZ exposure in a dose-dependent manner. Moreover, addicsin was co-localized with the plasma membrane markers EAAC1 and Na⁺/K⁺ ATPase alpha-3 upon PTZ stimulation. This translocation was significantly inhibited by a non-competitive GABA_A receptor antagonist, picrotoxin, but not by a competitive GABA_A receptor antagonist, bicuculline. Furthermore, lactate dehydrogenase (LDH) assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay showed that PTZ-induced addicsin translocation was accompanied by a decrease of radical-scavenging activity and an increase of cytotoxicity in a PTZ dose-dependent manner. These findings suggest that PTZ induces the translocation of addicsin from the ER to the plasma membrane and modulates the redox system by regulating EAAC1-mediated GSH synthesis, which leads to the activation of cell death signaling.