Pilocarpine-induced status epilepticus in mice: A comparison of spectral analysis of electroencephalogram and behavioral grading using the Racine scale

Neuroprotective potential of topiramate, pregabalin and lacosamide combination in a rat model of acute SE and intractable epilepsy: Perspectives from electroencephalographic, neurobehavioral and regional degenerative analysis

The lithium-pilocarpine model is commonly used to recapitulate characteristics of human intractable focal epilepsy. In the current study, we explored the impact of topiramate (TPM) alone and in combination with pregabalin and lacosamide administration for 6 weeks on the evolution of spontaneous recurrent seizures (SRS) and disease-modifying potential on associated neuropsychiatric comorbidities. In addition, redox impairments and neurodegeneration in hippocampus regions vulnerable to temporal lobe epilepsy (TLE) were assessed by cresyl violet staining. Results revealed that acute electrophysiological (EEG) profiling of the ASD cocktail markedly halted sharp ictogenic spikes as well as altered dynamics of brain wave oscillations thus validating the need for polytherapy vs. monotherapy. In TLE animals, pharmacological intervention for 6 weeks with topiramate 10 mg/kg in combination with PREG and LAC at the dose of 20 mg/kg exhibited marked protection from SRS incidence, improved body weight, offensive aggression, anxiety-like behavior, cognitive impairments, and depressive-like behavior (p < 0.05). Moreover, combination therapy impeded redox impairments as evidenced by decreased MDA and AchE levels and increased activity of antioxidant SOD, GSH enzymes. Furthermore, polytherapy rescued animals from SE-induced neurodegeneration with increased neuronal density in CA1, CA3c, CA3ab, hilus, and granular cell layer (GCL) of the dentate gyrus. In conclusion, early polytherapy with topiramate in combination with pregabalin and lacosamide prompted synergy and prevented epileptogenesis with associated psychological and neuropathologic alterations.

A Novel Rat Infant Model of Medial Temporal Lobe Epilepsy Reveals New Insight into the Molecular Biology and Epileptogenesis in the Developing Brain

Although several adult rat models of medial temporal lobe epilepsy (mTLE) have been described in detail, our knowledge of mTLE epileptogenesis in infant rats is limited. Here, we present a novel infant rat model of mTLE (InfRPil-mTLE) based on a repetitive, triphasic injection regimen consisting of low-dose pilocarpine administrations (180 mg/kg. i.p.) on days 9, 11, and 15 post partum (pp). The model had a survival rate of >80% and exhibited characteristic spontaneous recurrent electrographic seizures (SRES) in both the hippocampus and cortex that persisted into adulthood. Using implantable video-EEG radiotelemetry, we quantified a complex set of seizure parameters that demonstrated the induction of chronic electroencephalographic seizure activity in our InfRPil-mTLE model, which predominated during the dark cycle. We further analyzed selected candidate genes potentially relevant to epileptogenesis using a RT-qPCR approach. Several candidates, such as the low-voltage-activated Ca2+ channel Cav3.2 and the auxiliary subunits β 1 and β 2, which were previously reported to be upregulated in the hippocampus of the adult pilocarpine mTLE model, were found to be downregulated (together with Cav2.1, Cav2.3, M1, and M3) in the hippocampus and cortex of our InfRPil-mTLE model. From a translational point of view, our model could serve as a blueprint for childhood epileptic disorders and further contribute to antiepileptic drug research and development in the future.

Evaluation of Wnt/β-catenin signaling and its modulators in repeated dose lithium-pilocarpine rat model of status epilepticus: An acute phase study

The role of the Wnt/β-catenin signaling pathway in epilepsy and the effects of its modulators as efficacious treatment options, though postulated, has not been sufficiently investigated. We evaluated the involvement of β-catenin and GSK-3β, the significant proteins in this pathway, in the lithium chloride-pilocarpine-induced status epilepticus model in rodents to study acute phase of temporal lobe epilepsy (TLE). The modulators studied were 6-BIO, a GSK-3β inhibitor and Sulindac, a Dvl protein inhibitor. The disease group exhibited increased seizure score and seizure frequency, and the assessment of neurobehavioral parameters indicated notable alterations. Furthermore, histopathological examination of hippocampal brain tissues revealed significant neurodegeneration. Immunohistochemical study of hippocampus revealed neurogenesis in 6-BIO and sulindac groups. The gene and protein expression by RT-qPCR and western blotting studies indicated Wnt/β-catenin pathway downregulation and increased apoptosis in the acute phase of TLE. 6-BIO was very efficient in upregulating the Wnt pathway, decreasing neuronal damage, increasing neurogenesis in hippocampus and decreasing seizure score and frequency in comparison to sulindac. This suggests that both GSK-3β and β-catenin are potential and novel drug targets for acute phase of TLE, and treatment options targeting these proteins could be beneficial in successfully managing acute epilepsy. Further evaluation of 6-BIO to explore its therapeutic potential in other models of epilepsy should be conducted.

Increased Susceptibility to Pilocarpine-Induced Status Epilepticus and Reduced Latency in TRPC1/4 Double Knockout Mice

Canonical transient receptor potential channels (TRPCs) are a family of calcium-permeable cation channels. Previous studies have shown that heteromeric channels comprising TRPC1 and TRPC4 mediate epileptiform bursting in lateral septal neurons and hippocampal CA1 pyramidal neurons, suggesting that TRPC1/4 channels play a pro-seizure role. In this study, we utilized electroencephalography (EEG) recording and spectral analysis to assess the role of TRPC1/4 channels in the pilocarpine model of status epilepticus (SE). We found that, surprisingly, TRPC1/4 double knockout (DKO) mice exhibited an increased susceptibility to pilocarpine-induced SE. Furthermore, SE latency was also significantly reduced in TRPC1/4 DKO mice. Further studies are needed to reveal the underlying mechanisms of our unexpected results.

Investigation of the mechanism of tanshinone IIA to improve cognitive function via synaptic plasticity in epileptic rats

CONTEXT

Tanshinone IIA is an extract of Salvia miltiorrhiza Bunge (Labiatae) used to treat cardiovascular disorders. It shows potential anticonvulsant and cognition-protective properties.

OBJECTIVE

We investigated the mechanism of tanshinone IIA on antiepileptic and cognition-protective effects in the model of epileptic rats.

MATERIALS AND METHODS

Lithium chloride (LiCl)-pilocarpine-induced epileptic Wistar rats were randomly assigned to the following groups (n = 12): control (blank), model, sodium valproate (VPA, 189 mg/kg/d, positive control), tanshinone IIA low dose (TS IIA-L, 10 mg/kg/d), medium dose (TS IIA-M, 20 mg/kg/d) and high dose (TS IIA-H, 30 mg/kg/d). Then, epileptic behavioural observations, Morris water maze test, Timm staining, transmission electron microscopy, immunofluorescence staining, western blotting and RT-qPCR were measured.

RESULTS

Compared with the model group, tanshinone IIA reduced the frequency and severity of seizures, improved cognitive impairment, and inhibited hippocampal mossy fibre sprouting score (TS IIA-M 1.50 ± 0.22, TS IIA-H 1.17 ± 0.31 vs. model 2.83 ± 0.31), as well as improved the ultrastructural disorder. Tanshinone IIA increased levels of synapse-associated proteins synaptophysin (SYN) and postsynaptic dense substance 95 (PSD-95) (SYN: TS IIA 28.82 ± 2.51, 33.18 ± 2.89, 37.29 ± 1.69 vs. model 20.23 ± 3.96; PSD-95: TS IIA 23.10 ± 0.91, 26.82 ± 1.41, 27.00 ± 0.80 vs. model 18.28 ± 1.01).

DISCUSSION AND CONCLUSIONS

Tanshinone IIA shows antiepileptic and cognitive function-improving effects, primarily via regulating synaptic plasticity. This research generates a theoretical foundation for future research on potential clinical applications for tanshinone IIA.

MicroRNA-218 instructs proper assembly of hippocampal networks

The assembly of the mammalian brain is orchestrated by temporally coordinated waves of gene expression. Post-transcriptional regulation by microRNAs (miRNAs) is a key aspect of this program. Indeed, deletion of neuron-enriched miRNAs induces strong developmental phenotypes, and miRNA levels are altered in patients with neurodevelopmental disorders. However, the mechanisms used by miRNAs to instruct brain development remain largely unexplored. Here, we identified miR-218 as a critical regulator of hippocampal assembly. MiR-218 is highly expressed in the hippocampus and enriched in both excitatory principal neurons (PNs) and GABAergic inhibitory interneurons (INs). Early life inhibition of miR-218 results in an adult brain with a predisposition to seizures. Changes in gene expression in the absence of miR-218 suggest that network assembly is impaired. Indeed, we find that miR-218 inhibition results in the disruption of early depolarizing GABAergic signaling, structural defects in dendritic spines, and altered intrinsic membrane excitability. Conditional knockout of Mir218-2 in INs, but not PNs, is sufficient to recapitulate long-term instability. Finally, de-repressing Kif21b and Syt13, two miR-218 targets, phenocopies the effects on early synchronous network activity induced by miR-218 inhibition. Taken together, the data suggest that miR-218 orchestrates formative events in PNs and INs to produce stable networks.

GABA content and an antioxidant profile positively correlated with the anticonvulsive activity of Microcos paniculata in acute seizure mice

This study evaluated the effects of different parts of M. paniculata (MP) extracts on convulsions and antioxidant activities in mice. Six polyphenolic compounds were identified, where epicatechin and quercetin have been identified in the highest amounts (23.01 and 32.23 mg/100 g of dry MP extract, respectively) in MP leaf and stem extracts, using Ultra Performance Liquid Chromatography. 7-day oral administration of MP at doses of 100, 200, and 400 mg/kg body weight (BW) significantly reduced convulsions and reduced mortality rates compared with seizure inducer groups. Antioxidant potentials were measured by superoxide dismutase (SOD), catalase (CAT), thiobarbituric acid reactive substances (TBARS), and reduced glutathione (GSH) content in whole-brain homogenates. Gamma-aminobutyric acid (GABA) levels significantly increased in leaves and stem-treated groups, suggesting that MP leaves and stems have potent antioxidant properties that can attenuate convulsions by modulating the GABAergic system and antioxidant activities.

Unwinding the modalities of necrosome activation and necroptosis machinery in neurological diseases

Necroptosis, a regulated form of cell death, is involved in the genesis and development of various life-threatening diseases, including cancer, neurological disorders, cardiac myopathy, and diabetes. Necroptosis initiates with the formation and activation of a necrosome complex, which consists of RIPK1, RIPK2, RIPK3, and MLKL. Emerging studies has demonstrated the regulation of the necroptosis cell death pathway through the implication of numerous post-translational modifications, namely ubiquitination, acetylation, methylation, SUMOylation, hydroxylation, and others. In addition, the negative regulation of the necroptosis pathway has been shown to interfere with brain homeostasis through the regulation of axonal degeneration, mitochondrial dynamics, lysosomal defects, and inflammatory response. Necroptosis is controlled by the activity and expression of signaling molecules, namely VEGF/VEGFR, PI3K/Akt/GSK-3β, c-Jun N-terminal kinases (JNK), ERK/MAPK, and Wnt/β-catenin. Herein, we briefly discussed the implication and potential of necrosome activation in the pathogenesis and progression of neurological manifestations, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, traumatic brain injury, and others. Further, we present a detailed picture of natural compounds, micro-RNAs, and chemical compounds as therapeutic agents for treating neurological manifestations.

Zinc oxide calcium silicate composite attenuates acute tramadol toxicity in mice

BACKGROUND

Seizures are considered to be the most common symptom encountered in emergency- rushed tramadol-poisoned patients; accounting for 8% of the drug-induced seizure cases. Although, diazepam clears these seizures, the risk of central respiratory depression cannot be overlooked. Henceforth, three adsorbing composites were examined in a tramadol acute intoxication mouse model.

METHODS

Calcium Silicate (Wollastonite) either non-doped or wet doped with iron oxide (3%Fe₂O₃) or zinc oxide (30% ZnO) were prepared. The composites' adsorption capacity for tramadol was determined in vitro. Tramadol intoxication was induced in Swiss albino mice by a parenteral dose of 120 mg/kg. Proposed treatments were administered within 1 min at 5 increasing doses, i.p. The next 30 min, seizures were monitored as an intoxication symptom. Plasma tramadol concentration was recorded after two hours of administration.

RESULTS

The 3% Fe₂O₃-containing composite (CSFe3), was found to be composed of mainly wollastonite with very little alpha-hematite. On the other hand, hardystonite and wellimite were developed in the 30%ZnO-containing composite (CSZn3). Micro-round and irregular nano-sized microstructures were established (The particle size of CS was 56 nm, CSFe3 was 49 nm, and CSZn3 was 42 nm). The CSZn3 adsorption capacity reached 1497 mg of tramadol for each gram. Tramadol concentration was reduced in plasma and seizures were inhibited after its administration to mice at three doses.

CONCLUSION

The calcium silicate composite doped with ZnO presented a good resolution of tramadol-induced seizures accompanied by detoxification of blood, indicating its potential for application in such cases. Further studies are required.

Convulsant doses of abused synthetic cannabinoid receptor agonists AB-PINACA, 5F-AB-PINACA, 5F-ADB-PINACA and JWH-018 do not elicit electroencephalographic (EEG) seizures in male mice

RATIONALE

Synthetic cannabinoid receptor agonists (SCRAs) are found in illicit smoking products, such as "K2" or "Spice." Convulsions are commonly reported adverse effects of SCRAs but are poorly understood.

OBJECTIVES

We determined convulsant effects of SCRAs AB-PINACA, and 5F-ADB-PINACA in adult male NIH Swiss mice, and then determined if convulsant effects of AB-PINACA, 5F-AB-PINACA, 5F-ADB-PINACA, and JWH-018 elicited seizure-like effects using EEG.

METHODS

Mice were administered SCRAs or pentylenetetrazole (PTZ) and placed in observation chambers where convulsant effects were scored. The capacity of the CB1R antagonist rimonabant, the benzodiazepine diazepam, or the non-specific CYP450 inhibitor 1-aminobenzotriazole (1-ABT) to attenuate convulsant effects was determined. Other mice were prepared with EEG headmounts to ascertain whether observed convulsions occurred concurrently with seizure-like effects by assessing root-mean-square (RMS) power, high amplitude EEG spike analysis, and videography.

RESULTS

Mice receiving AB-PINACA or 5F-ADB-PINACA exhibited dose-dependent convulsant effects that were blocked by 10 mg/kg rimonabant pretreatment but not by pretreatment with 10 mg/kg diazepam; these convulsant effects were not altered in the presence of 100 mg/kg 1-ABT. Repeated administration of 10 mg/kg AB-PINACA and 3 mg/kg 5F-ADB-PINACA produced partial tolerance to convulsant effects but did not lead to cross-tolerance to PTZ-induced convulsions. In EEG studies, convulsant doses of AB-PINACA, 5F-AB-PINACA, 5F-ADB-PINACA, and JWH-018 did not produce seizures concomitantly with convulsions.

CONCLUSIONS

These data extend previous findings of convulsant effects of SCRAs and suggest that convulsant effects of AB-PINACA, 5F-AB-PINACA, 5F-ADB-PINACA, and JWH-018 are CB1R-mediated but are not associated with electroencephalographic seizures. These results further suggest that benzodiazepines may not effectively treat convulsions elicited by SCRA use in humans.

Elevated TNF-α Leads to Neural Circuit Instability in the Absence of Interferon Regulatory Factor 8

Interferon regulatory factor 8 (IRF8) is a transcription factor necessary for the maturation of microglia, as well as other peripheral immune cells. It also regulates the transition of microglia and other immune cells to a pro-inflammatory phenotype. Irf8 is also a known risk gene for multiple sclerosis and lupus, and it has recently been shown to be downregulated in schizophrenia. While most studies have focused on IRF8-dependent regulation of immune cell function, little is known about how it impacts neural circuits. Here, we show by RNAseq from Irf8 -/- male and female mouse brains that several genes involved in regulation of neural activity are dysregulated. We then show that these molecular changes are reflected in heightened neural excitability and a profound increase in susceptibility to lethal seizures in male and female Irf8 -/- mice. Finally, we identify that TNF-α is elevated specifically in microglia in the CNS, and genetic or acute pharmacological blockade of TNF-α in the Irf8 -/- CNS rescued the seizure phenotype. These results provide important insights into the consequences of IRF8 signaling and TNF-α on neural circuits. Our data further suggest that neuronal function is impacted by loss of IRF8, a factor involved in neuropsychiatric and neurodegenerative diseases.SIGNIFICANCE STATEMENT Here, we identify a previously unknown and key role for interferon regulator factor 8 (IRF8) in regulating neural excitability and seizures. We further determine that these effects on neural circuits are through elevated TNF-α in the CNS. As IRF8 has most widely been studied in the context of regulating the development and inflammatory signaling in microglia and other immune cells, we have uncovered a novel function. Further, IRF8 is a risk gene for multiple sclerosis and lupus, IRF8 is dysregulated in schizophrenia, and elevated TNF-α has been identified in a multitude of neurologic conditions. Thus, elucidating these IRF8 and TNF-α-dependent effects on brain circuit function has profound implications for understanding underlying, therapeutically relevant mechanisms of disease.

Effects of Sublethal Organophosphate Toxicity and Anti-cholinergics on Electroencephalogram and Respiratory Mechanics in Mice

Organophosphates are used in agriculture as insecticides but are potentially toxic to humans when exposed at high concentrations. The mechanism of toxicity is through antagonism of acetylcholinesterase, which secondarily causes excess activation of cholinergic receptors leading to seizures, tremors, respiratory depression, and other physiological consequences. Here we investigated two of the major pathophysiological effects, seizures and respiratory depression, using subcutaneous injection into mice of the organophosphate diisopropylfluorophosphate (DFP) at sublethal concentrations (2.1 mg/Kg) alone and co-injected with current therapeutics atropine (50 mg/Kg) or acetylcholinesterase reactivator HI6 (3 mg/Kg). We also tested a non-specific cholinergic antagonist dequalinium chloride (2 mg/Kg) as a novel treatment for organophosphate toxicity. Electroencephalogram (EEG) recordings revealed that DFP causes focal delta frequency (average 1.4 Hz) tonic spikes in the parietal region that occur transiently (lasting an average of 171 ± 33 min) and a more sustained generalized theta frequency depression in both parietal and frontal electrode that did not recover the following 24 h. DFP also caused behavioral tremors that partially recovered the following 24 h. Using whole body plethysmography, DFP revealed acute respiratory depression, including reduced breathing rates and tidal volumes, that partially recover the following day. Among therapeutic treatments, dequalinium chloride had the most potent effect on all physiological parameters by reducing acute EEG abnormalities and promoting a full recovery after 24 h from tremors and respiratory depression. Atropine and HI6 had distinct effects on EEGs. Co-treatment with atropine converted the acute 1.4 Hz tonic spikes to 3 Hz tonic spikes in the parietal electrode and promoted a partial recovery after 24 h from theta frequency and respiratory depression. HI6 fully removed the parietal delta spike increase and promoted a full recovery in theta frequency and respiratory depression. In summary, while all anticholinergic treatments promoted survival and moderated symptoms of DFP toxicity, the non-selective anti-cholinergic dequalinium chloride had the most potent therapeutic effects in reducing EEG abnormalities, moderating tremors and reducing respiratory depression.

An aqueous extract of Khaya senegalensis (Desv.) A. Juss. (Meliaceae) prevents seizures and reduces anxiety in kainate-treated rats: modulation of GABA neurotransmission, oxidative stress, and neuronal loss in the hippocampus

Ethnopharmacological relevance

Temporal lobe epilepsy is the most common form of drug-resistant epilepsy. Therefore, medicinal plants provide an alternative source for the discovery of new antiepileptic drugs.

Aim of the study

This study was aimed at investigating the antiepileptic- and anxiolytic-like effects of an aqueous extract of Khaya senegalensis (K. senegalensis) in kainate-treated rats.

Methods

Seventy-two rats received a single dose of kainate (12 mg/kg) intraperitoneally. Those that exhibited two hours of status epilepticus were selected and monitored for the first spontaneous seizure. Then, animals that developed seizures were divided into 6 groups of 8 rats each and treated twice daily for 14 days as follows: negative control group received per os (p.o.) distilled water (10 ml/kg); two positive control groups received either sodium valproate (300 mg/kg, p.o.) or phenobarbital (20 mg/kg, p.o.); and three test groups received different doses of the extract (50, 100, and 200 mg/kg, p.o.). In addition, a group of 8 normal rats (normal control group) received distilled water (10 ml/kg, p.o.). During the treatment period, the animals were video-monitored 12 h/day for behavioral seizures. At the end of the treatment period, animals were subjected to elevated plus-maze and open field tests. Thereafter, rats were euthanized for the analysis of γ-aminobutyric acid (GABA) concentration, oxidative stress status, and neuronal loss in the hippocampus.

Results

The aqueous extract of K. senegalensis significantly reduced spontaneous recurrent seizures (generalized tonic-clonic seizures) and anxiety-like behavior compared to the negative control group. These effects were more marked than those of sodium valproate or phenobarbital. Furthermore, the extract significantly increased GABA concentration, alleviated oxidative stress, and mitigated neuronal loss in the dentate gyrus of the hippocampus.

Conclusion

These findings suggest that the aqueous extract of K. senegalensis possesses antiepileptic- and anxiolytic-like effects. These effects were greater than those of sodium valproate or phenobarbital, standard antiepileptic drugs. Furthermore, these effects are accompanied by neuromodulatory and antioxidant activities that may be related to their behavioral effects. These data justify further studies to identify the bioactive molecules present in the extract for possible future therapeutic development and to unravel their mechanisms of action.

Inhibition of TRPC3 channels by a novel pyrazole compound confers antiseizure effects

OBJECTIVE

As a key member of the transient receptor potential (TRP) superfamily, TRP canonical 3 (TRPC3) regulates calcium homeostasis and contributes to neuronal excitability. Ablation of TRPC3 lessens pilocarpine-induced seizures in mice, suggesting that TRPC3 inhibition might represent a novel antiseizure strategy. Among current TRPC3 inhibitors, pyrazole 3 (Pyr3) is most selective and potent. However, Pyr3 only provides limited benefits in pilocarpine-treated mice, likely due to its low metabolic stability and potential toxicity. We recently reported a modified pyrazole compound 20 (or JW-65) that has improved stability and safety. The objective of this study was to explore the effects of TRPC3 inhibition by our current lead compound JW-65 on seizure susceptibility.

METHODS

We first examined the pharmacokinetic properties including plasma half-life and brain to plasma ratio of JW-65 after systemic administration in mice. We then investigated the effects of TRPC3 inhibition by JW-65 on behavioral and electrographic seizures in mice treated with pilocarpine. To ensure our findings are not model specific, we assessed the susceptibility of JW-65-treated mice to pentylenetetrazole (PTZ)-induced seizures with phenytoin as a comparator.

RESULTS

JW-65 showed adequate half-life and brain penetration in mice, justifying its use for central nervous system conditions. Systemic treatment with JW-65 before pilocarpine injection in mice markedly impaired the initiation of behavioral seizures. This antiseizure action was recapitulated when JW-65 was administered after pilocarpine-induced behavioral seizures were well established and was confirmed by time-locked electroencephalographic monitoring and synchronized video. Moreover, JW-65-treated mice showed substantially decreased susceptibility to PTZ-induced seizures in a dose-dependent manner.

SIGNIFICANCE

These results suggest that pharmacological inhibition of the TRPC3 channels by our novel compound JW-65 might represent a new antiseizure strategy engaging a previously undrugged mechanism of action. Hence, this proof-of-concept study establishes TRPC3 as a novel feasible therapeutic target for the treatment of some forms of epilepsy.

Intravenous kainic acid induces status epilepticus and late onset seizures in mice

We set out to establish a novel model of temporal lobe epilepsy (TLE) in a mouse. We sought to induce TLE through the injection of kainic acid (KA) into the tail vein with subsequent development of status epilepticus (SE). Using C57BL/6 mice, we implanted hippocampal EEG recording electrodes before or after injection of KA or phosphate buffered saline (PBS). Video and EEG analysis were conducted to evaluate for SE and development of recurrent seizures, the hallmark of TLE. All mice injected with KA developed SE while those who were injected with PBS did not. Of the animals injected with KA monitored for recurrent seizures following SE, 33% developed spontaneous recurrent seizures while those injected with PBS did not. Injection of KA through the tail vein of a mouse reliably and rapidly induces SE which remits spontaneously and leads to the development of TLE in a subset of mice.

Substantial outcome improvement using a refined pilocarpine mouse model of temporal lobe epilepsy

Systemic pilocarpine treatment is one of the most reliable means of inducing temporal lobe epilepsy (TLE). However, the traditional pilocarpine injection protocol using mice was associated with a high death rate, possibly because of cardiorespiratory collapse following status epilepticus (SE). To prevent this, we developed a modified procedure of pilocarpine SE induction, which included a single injection of a moderate dose of caffeine during the induction phase. That new protocol was based on the use of young male mice as well as on a refined Racine's scale. Using that protocol, we report a substantially increased survival rate, thus enabling the generation of a large cohort of mice that exhibited cardinal histological (e.g., mossy fiber sprouting) and electrophysiological (e.g., chronic interictal events and ictal seizures) characteristics associated with TLE. In conclusion, our refined caffeine- and pilocarpine-based protocol substantially improves the outcome of the reliable pilocarpine mouse model of TLE.

Sex-specific acute and chronic neurotoxicity of acute diisopropylfluorophosphate (DFP)-intoxication in juvenile Sprague-Dawley rats

Preclinical efforts to improve medical countermeasures against organophosphate (OP) chemical threat agents have largely focused on adult male models. However, age and sex have been shown to influence the neurotoxicity of repeated low-level OP exposure. Therefore, to determine the influence of sex and age on outcomes associated with acute OP intoxication, postnatal day 28 Sprague-Dawley male and female rats were exposed to the OP diisopropylfluorophosphate (DFP; 3.4 mg/kg, s.c.) or an equal volume of vehicle (∼80 µL saline, s.c.) followed by atropine sulfate (0.1 mg/kg, i.m.) and pralidoxime (2-PAM; 25 mg/kg, i.m.). Seizure activity was assessed during the first 4 h post-exposure using behavioral criteria and electroencephalographic (EEG) recordings. At 1 d post-exposure, acetylcholinesterase (AChE) activity was measured in cortical tissue, and at 1, 7, and 28 d post-exposure, brains were collected for neuropathologic analyses. At 1 month post-DFP, animals were analyzed for motor ability, learning and memory, and hippocampal neurogenesis. Acute DFP intoxication triggered more severe seizure behavior in males than females, which was supported by EEG recordings. DFP caused significant neurodegeneration and persistent microglial activation in numerous brain regions of both sexes, but astrogliosis occurred earlier and was more severe in males compared to females. DFP males and females exhibited pronounced memory deficits relative to sex-matched controls. In contrast, acute DFP intoxication altered hippocampal neurogenesis in males, but not females. These findings demonstrate that acute DFP intoxication triggers seizures in juvenile rats of both sexes, but the seizure severity varies by sex. Some, but not all, chronic neurotoxic outcomes also varied by sex. The spatiotemporal patterns of neurological damage suggest that microglial activation may be a more important factor than astrogliosis or altered neurogenesis in the pathogenesis of cognitive deficits in juvenile rats acutely intoxicated with OPs.

An aqueous extract of Canarium schweinfurthii attenuates seizures and potentiates sleep in mice: Evidence for involvement of GABA Pathway

About 30% of epileptic patients continue to have seizures. The present study investigates the anticonvulsant and sedative effects of an aqueous extract of C. schweinfurthii in mice. Anticonvulsant effects of C. schweinfurthii aqueous extract (0.01-300 mg/kg, p.o.) were tested against 4-aminopyridine (4-AP, 15 mg/kg, i.p.) -, pilocarpine (PILO, 380 mg/kg, i.p.) - and pentylenetetrazole (PTZ, 75 mg/kg, i.p.) -induced seizures, while sedative effects were tested on diazepam (35 mg/kg, i.p.)-induced sleep. Afterward, the most effective dose of the extract (11.9 mg/kg) was antagonized with N-methyl-β-carboline-3-carboxamide or flumazenil. In another set of experiments, mice were sacrificed for the estimation of GABA content and GABA-T activity in the cerebral cortex. The dose of the extract that protected 50% of mice (ED₅₀) against 4-AP, PILO, and PTZ was respectively 4.43 mg/kg (versus 12.01 for phenobarbital), 9.59 mg/kg (vs 8.67 for diazepam), and 2.12 mg/kg (vs 0.20 for clonazepam). Further, the ED₅₀ of the extract that increased the duration of sleep was 0.24 mg/kg (vs 0.84 for phenobarbital). N-methyl-β-carboline-3-carboxamide or flumazenil antagonized (p < 0.001) the anticonvulsant effect of C. schweinfurthii in PTZ-induced seizures and diazepam-induced sleep when compared to the negative control group. The extract at all doses increased (p < 0.001) the GABA content and decreased (p < 0.001) GABA-T activity. These findings suggest that C. schweinfurthii possesses anticonvulsant and sedative effects. These effects seem to be mediated via the modulation of the GABA neurotransmission. These data explain the use of this plant to treat epilepsy in Cameroon traditional medicine.

Cortical low-frequency power correlates with behavioral impairment in animal model of focal limbic seizures

OBJECTIVE

Impairment in consciousness is a debilitating symptom during and after seizures; however, its mechanism remains unclear. Limbic seizures have been shown to spread to arousal circuitry to result in a "network inhibition" phenomenon. However, prior animal model studies did not relate physiological network changes to behavioral responses during or following seizures.

METHODS

Focal onset limbic seizures were induced while rats were performing an operant conditioned behavioral task requiring response to an auditory stimulus to quantify how and when impairment of behavioral response occurs. Correct responses were rewarded with sucrose. Cortical and hippocampal electrophysiology measured by local field potential recordings was analyzed for changes in low- and high-frequency power in relation to behavioral responsiveness during seizures.

RESULTS

As seen in patients with seizures, ictal (p < .0001) and postictal (p = .0015) responsiveness was variably impaired. Analysis of cortical and hippocampal electrophysiology revealed that ictal (p = .002) and postictal (p = .009) frontal cortical low-frequency 3-6-Hz power was associated with poor behavioral performance. In contrast, the hippocampus showed increased power over a wide frequency range during seizures, and suppression postictally, neither of which were related to behavioral impairment.

SIGNIFICANCE

These findings support prior human studies of temporal lobe epilepsy as well as anesthetized animal models suggesting that focal limbic seizures depress consciousness through remote network effects on the cortex, rather than through local hippocampal involvement. By identifying the cortical physiological changes associated with impaired arousal and responsiveness in focal seizures, these results may help guide future therapies to restore ictal and postictal consciousness, improving quality of life for people with epilepsy.

Persistent brainwave disruption and cognitive impairment induced by acute sarin surrogate sub-lethal dose exposure

Warfare neurotoxicants such as sarin, soman or VX, are organophosphorus compounds which irreversibly inhibit cholinesterase. High-dose exposure with nerve agents (NA) is known to produce seizure activity and related brain damage, while less is known about the effects of acute sub-lethal dose exposure. The aim of this study was to characterize behavioral, brain activity and neuroinflammatory modifications at different time points after exposure to 4-nitrophenyl isopropyl methylphosphonate (NIMP), a sarin surrogate. In order to decipher the impacts of sub-lethal exposure, we chose 4 different doses of NIMP each corresponding to a fraction of the median lethal dose (LD₅₀). First, we conducted a behavioral analysis of symptoms during the first hour following NIMP challenge and established a specific scoring scale for the intoxication severity. The intensity of intoxication signs was dose-dependent and proportional to the cholinesterase activity inhibition evaluated in mice brain. The lowest dose (0.3 LD₅₀) did not induce significant behavioral, electrocorticographic (ECoG) nor cholinesterase activity changes. Animals exposed to one of the other doses (0.5, 0.7 and 0.9 LD₅₀) exhibited substantial changes in behavior, significant cholinesterase activity inhibition, and a disruption of brainwave distribution that persisted in a dose-dependent manner. To evaluate long lasting changes, we conducted ECoG recording for 30 days on mice exposed to 0.5 or 0.9 LD₅₀ of NIMP. Mice in both groups showed long-lasting impairment of theta rhythms, and a lack of restoration in hippocampal ChE activity after 1-month post-exposure. In addition, an increase in neuroinflammatory markers (IBA-1, TNF-α, NF-κB) and edema were transiently observed in mice hippocampus. Furthermore, a novel object recognition test showed an alteration of short-term memory in both groups, 1-month post-NIMP intoxication. Our findings identified both transient and long-term ECoG alterations and some long term cognitive impairments following exposure to sub-lethal doses of NIMP. These may further impact morphopathological alterations in the brain.

Gastrodin alleviates seizure severity and neuronal excitotoxicities in the rat lithium-pilocarpine model of temporal lobe epilepsy via enhancing GABAergic transmission

ETHNOPHARMACOLOGICAL RELEVANCE

Temporal lobe epilepsy remains one of the most drug-resistant focal epilepsy, leading to enormous healthcare burden. Among traditional herb medicine, some ingredients have the potential to treat seizure and alleviate the neuronal excitoxicity. The dried rhizome of Gastrodia elata Blume has been used to treat convulsive disorder, dizziness, dementia and migraine in eastern Asia.

AIM OF THE STUDY

To determine whether gastrodin, an active ingredient of Gastrodia elata Blume, can reduce lithium-pilocarpine induced seizure severity and neuronal excitotoxicity and explore the underlying mechanism.

MATERIALS AND METHODS

We divided the Sprague-Dawley rats into an experimental group (gastrodin group) and a control group (Dimethyl sulfoxide, vehicle group) and performed the behavioral analysis and electroencephalography to determine the effect of gastrodin on the seizure severity induced by lithium-pilocarpine injection. Nissl-stained histopathology elucidated the degree of rat hippocampal neuronal damage as markers of acute and subacute neuronal excitotoxicity. Besides, the Western blotting of dissected hippocampus was carried out to demonstrate the protein expression involving GABAergic transmission and metabolic pathway.

RESULTS

Gastrodin reduced the acute seizure severity in lithium-pilocarpine-induced seizure model. In electroencephalography recording, gastrodin exerted inhibitory action on epileptiform discharge. Compared with control group, gastrodin exhibited neuroprotective effect against seizure related hippocampal neuronal damage at acute and subacute stages. The Western blotting showed that gastrodin reversed the degradation of GABAA receptor after pilocarpine-induced seizures.

CONCLUSIONS

In the experimental seizure model, gastrodin showed anti-seizure and neuroprotective abilities. Enhancing the expression of GABAA receptor plays an important role in its antiepileptic mechanism. The results offer a new insight of developing new antiepileptic drugs from traditional Chinese medicine.

The TAAR1 inhibitor EPPTB suppresses neuronal excitability and seizure activity in mice

Epilepsy is a common neurological disease. G protein-coupled receptors (GPCRs) are extensively distributed and play an important role in human health by serving as therapeutic targets for various diseases. As one of the GPCRs, trace amine-associated receptor 1 (TAAR1) has recently aroused increasing interest as a potential therapeutic target for psychiatric disorders. However, the effect of TAAR1 on epileptic seizures remains unclear. We hypothesized that TAAR1 plays an important role in epilepsy and might represent a potential therapeutic target. In this study, we analyzed a mouse epilepsy model and patients with temporal lobe epilepsy (TLE) and observed substantially increased TAAR1 expression compared with the control group. In recordings of hippocampal slices, the TAAR1-specific inhibitor N-(3-ethoxyphenyl)-4-(pyrrolidin-1-yl)-3-(trifluoromethyl) benzamide (EPPTB) suppressed the excitability of hippocampal pyramidal neurons. EPPTB also reduced seizure-like events (SLEs) and seizure activity. Our results suggest that EPPTB attenuates seizure activity and that TAAR1 might be a potential drug target for individuals with epilepsy.

Zingerone Targets Status Epilepticus by Blocking Hippocampal Neurodegeneration via Regulation of Redox Imbalance, Inflammation and Apoptosis

Epilepsy is an intricate neurological disease where the neurons are severely affected, leading to the mortality of millions worldwide. Status epilepticus (SE), induced by lithium chloride (LiCl) and pilocarpine, is the most accepted model for epilepsy. The current work aims to unravel the mechanisms underlying the anti-epileptic efficacy of zingerone (an active ingredient of ginger), which has beneficial pharmacological activities on seizure-induced behavioral, histological, neurochemical, and molecular patterns in mice. Zingerone restored cognitive function by diminishing seizure activity, escape latency, and subsequent hippocampal damage manifested in histology. Seizures are associated with local inflammation, redox imbalance, and neural loss, confirmed by the present study of SE, and was attenuated by zingerone treatment. Nuclear factor-kappa B and its downstream signaling molecules (TNF-α, IL-1β, IL-6, NO, MPO) were activated in the LiCl-and-pilocarpine-induced group leading to inflammatory signaling, which was substantially ameliorated by zingerone treatment. The intrinsic apoptotic process was triggered subsequent to SE, as demonstrated by augmentation of cleaved caspase-3, downregulation of Bcl-2. However, zingerone treatment downregulated caspase-3 and upregulated Bcl-2, increasing cell survival and decreasing hippocampal neural death, deciphering involvement of apoptosis in SE. Therefore, zingerone plays an essential role in neuroprotection, probably by precluding oxidative stress, inflammation, and obstructing the mitochondrial pathway of apoptosis.

Apoptosis-antagonizing transcription factor is involved in rat post-traumatic epilepsy pathogenesis

The present study aimed to explore the pathogenesis behind post-traumatic epilepsy (PTE). In the present study, a chloride ferric injection-induced rat PTE model was established. The expression levels of apoptosis-antagonizing transcription factor (AATF), cleaved caspase-3, p53, Bcl-2 and Bax were measured by western blotting or immunofluorescence staining (IF). The expression of AATF in vivo was downregulated by microinjection of lentiviral-mediated short-hairpin RNA. Compared with control and sham groups, at day 5 after PTE, neuron apoptosis was significantly increased and the expression levels of AATF, p53, cleaved caspase-3 and Bax were significantly upregulated. In addition, IF revealed co-localization of AATF and cleaved caspase-3 in the cortex. Additionally, AATF was expressed mainly in neurons and astrocytes. Following AATF inhibition, the expression levels of p53 and cleaved caspase-3 were significantly reduced as compared with the control group. Taken together, these findings suggested that following PTE, AATF is involved in neuronal apoptosis and may serve as a potential target for its alleviation.

Effects of anterior thalamic nuclei stimulation on gene expression in a rat model of temporal lobe epilepsy

Deep brain stimulation of the anterior nucleus of the thalamus (ANT-DBS) has been shown to be effective and safe in the long-term treatment of refractory epilepsy. However, the mechanisms by which ANT-DBS controls epilepsy at the gene expression level (e.g., which regulatory mechanisms are altered) is not well understood. Nine rats were randomly assigned to the control group, the kainic acid (KA) group, and the DBS group. Temporal lobe epilepsy in rats was induced by a stereotaxic KA injection (KA group). The DBS group received the KA injection followed by treatment with ANT-DBS. Video-electroencephalogram (EEG) was used to monitor seizures. Total RNA samples were isolated from the hippocampus of three groups. Microarray was used to detect differentially regulated mRNAs. GO and pathway analysis were performed to analyze the functional categories and affected pathways. qPCR was used to prove the reliability of the microarray results. The differentially expressed genes the KA group and the DBS group, relative to the control group, were screened and a total of 2910 genes were identified. These genes were involved in functional categories such as ion channel activity (P = 5.01 × 10^-8), gated channel activity (P = 1.42 × 10^-7), lipid binding (P = 4.97 × 10^-5), and hydrolase activity (P = 5.02 × 10^-5) and pathways such as calcium signaling pathway (P = 2.09 × 10^-8), glutamatergic synapse (P = 4.09 × 10^-8) and NOD-like receptor signaling pathway (P = 2.70 × 10^-6). Differentially expressed mRNAs might play a role in the pathogenesis of temporal lobe epilepsy. Calcium signaling pathways, synaptic glutamate, and NOD-like receptor signaling pathway play a central role in normal-epilepsy-ANT-DBS treatment series. ANT-DBS achieves its antiepileptic effects by modulating target genes involved in a variety of functions and pathways.

Behavioral and EEGraphic Characterization of the Anticonvulsant Effects of the Predator Odor (TMT) in the Amygdala Rapid Kindling, a Model of Temporal Lobe Epilepsy

Background: Clinical and experimental evidence indicates that olfactory stimulation modulates limbic seizures, either blocking or inducing ictal activity.

Objective: We aim to evaluate the behavioral and electroencephalographic (EEGraphic) effects of dihydro-2,4,5-trimethylthiazoline (TMT) olfactory exposure on limbic seizures induced by amygdala rapid kindling (ARK).

Materials and Methods: Wistar male rats (280–300 g) underwent stereotaxic surgery for electrode implantation in piriform cortex (PC), hippocampal formation (HIP), and amygdaloid complex (AMYG). Part of the animals was exposed to a saturated chamber with water or TMT, while others had ARK and olfactory exposure prior to the 21st stimulus. Behavioral responses were measured by traditional seizure severity scales (Racine and Pinel and Rovner) and/or by sequential analysis/neuroethology. The electrographic activity of epileptogenic limbic networks was quantified by the occurrence of the first and second EEG afterdischarges, comparing the 1st and 21st stimulus. The spectral analysis [Fast Fourier Transform (FFT)] of the first afterdischarge was performed at the 21st stimulus.

Results: TMT olfactory exposure reduced the seizure severity in kindled rats, altering the displayed behavioral sequence. Moreover, TMT decreased the occurrence of first and second afterdischarges, at the 21st stimulus, and altered the spectral features.

Conclusions: Both behavioral and EEGraphic evaluations indicated that TMT, a potent molecule with strong biological relevance, in fact, “predator odor,” suppressed the epileptiform activity in limbic networks.

Baicalein Ameliorates Epilepsy Symptoms in a Pilocarpine-Induced Rat Model by Regulation of IGF1R

Treatment for epilepsy, particularly temporal lobe epilepsy, is challenging. Baicalein has multiple effects, including anti-inflammatory action. However, little is known about its efficacy in treatment of epilepsy. In this study, we established a pilocarpine-induced rat model and used it for assessment of baicalein efficacy in vivo. We predicted the pharmacological mechanism of baicalein by network pharmacology and RNA sequencing analyses. Pilocarpine epileptic rats treated with baicalein exhibited improved average seizure severity, seizure frequency, seizure duration, and survival time. Network pharmacology and RNA sequencing identified the differentially expressed genes between the baicalein treatment and epileptic groups. Insulin-like growth factor 1 receptor (IGF1R) was chosen as the top candidate target because of its overlapping findings in RNA sequencing and network pharmacology data. Western blotting, immunofluorescence, and polymerase chain reaction analyses showed that baicalein inhibited microglial proliferation, IGF1R, and inflammatory cytokine expression. Moreover, baicalein improved epilepsy symptoms. Inhibition of IGF1R function by blocking with AXL1717 enhanced baicalein treatment efficacy both in vivo and in vitro. In conclusion, baicalein exerted antiepileptic effects by regulation of IGF1R in a pilocarpine-induced rat model.

Neural Stem Cells and Cannabinoids in the Spotlight as Potential Therapy for Epilepsy

Epilepsy is one of the most common brain diseases worldwide, having a huge burden in society. The main hallmark of epilepsy is the occurrence of spontaneous recurrent seizures, having a tremendous impact on the lives of the patients and of their relatives. Currently, the therapeutic strategies are mostly based on the use of antiepileptic drugs, and because several types of epilepsies are of unknown origin, a high percentage of patients are resistant to the available pharmacotherapy, continuing to experience seizures overtime. Therefore, the search for new drugs and therapeutic targets is highly important. One key aspect to be targeted is the aberrant adult hippocampal neurogenesis (AHN) derived from Neural Stem Cells (NSCs). Indeed, targeting seizure-induced AHN may reduce recurrent seizures and shed some light on the mechanisms of disease. The endocannabinoid system is a known modulator of AHN, and due to the known endogenous antiepileptic properties, it is an interesting candidate for the generation of new antiepileptic drugs. However, further studies and clinical trials are required to investigate the putative mechanisms by which cannabinoids can be used to treat epilepsy. In this manuscript, we will review how cannabinoid-induced modulation of NSCs may promote neural plasticity and whether these drugs can be used as putative antiepileptic treatment.

Acute administration of diazepam or midazolam minimally alters long-term neuropathological effects in the rat brain following acute intoxication with diisopropylfluorophosphate

Acute intoxication with organophosphorus cholinesterase inhibitors (OPs) can trigger seizures that rapidly progress to life-threatening status epilepticus. Diazepam, long considered the standard of care for treating OP-induced seizures, is being replaced by midazolam. Whether midazolam is more effective than diazepam in mitigating the persistent effects of acute OP intoxication has not been rigorously evaluated. We compared the efficacy of diazepam vs. midazolam in preventing persistent neuropathology in adult male Sprague-Dawley rats acutely intoxicated with the OP diisopropylfluorophosphate (DFP). Subjects were administered pyridostigmine bromide (0.1 mg/kg, i.p.) 30 min prior to injection with DFP (4 mg/kg, s.c.) or vehicle (saline) followed 1 min later by atropine sulfate (2 mg/kg, i.m.) and pralidoxime (25 mg/kg, i.m.), and 40 min later by diazepam (5 mg/kg, i.p.), midazolam (0.73 mg/kg, i.m.), or vehicle. At 3 and 6 months post-exposure, neurodegeneration, reactive astrogliosis, microglial activation, and oxidative stress were assessed in multiple brain regions using quantitative immunohistochemistry. Brain mineralization was evaluated by in vivo micro-computed tomography (micro-CT). Acute DFP intoxication caused persistent neurodegeneration, neuroinflammation, and brain mineralization. Midazolam transiently mitigated neurodegeneration, and both benzodiazepines partially protected against reactive astrogliosis in a brain region-specific manner. Neither benzodiazepine attenuated microglial activation or brain mineralization. These findings indicate that neither benzodiazepine effectively protects against persistent neuropathological changes, and suggest that midazolam is not significantly better than diazepam. Overall, this study highlights the need for improved neuroprotective strategies for treating humans in the event of a chemical emergency involving OPs.

Serum Exosomal Proteins F9 and TSP-1 as Potential Diagnostic Biomarkers for Newly Diagnosed Epilepsy

Epilepsy is one of the most common chronic neurological diseases in the world, with a high incidence, a high risk of sudden unexplained death, and diagnostic challenges. Exosomes are nanosized extracellular vesicles that are released into physical environments and carry a variety of biological information. Moreover, exosomes can also be synthesized and released from brain cells, passing through the blood-brain barrier, and can be detected in peripheral blood or cerebrospinal fluid. Our study using the tandem mass tag (TMT) approach showed that a total of 76 proteins were differentially expressed in serum exosomes between epilepsy patients and healthy controls, with 6 proteins increasing and 70 proteins decreasing. Analysis of large clinical samples and two mouse models of chronic epilepsy indicated that two significantly differentially expressed serum exosomal proteins, coagulation factor IX (F9) and thrombospondin-1 (TSP-1), represent promising biomarkers for the diagnosis of epilepsy, with area under the curve (AUC) values of up to 0.7776 (95% CI, 0.7306–0.8246) and 0.8534 (95% CI, 0.8152–0.8916), respectively. This is the first study of exosomal proteins in epilepsy, and it suggests that exosomes are promising new tools for the diagnosis of epilepsy.

Diverged morphology changes of astrocytic and neuronal primary cilia under reactive insults

Primary cilia are centriole-derived sensory organelles that are present in most mammalian cells, including astrocytes and neurons. Evidence is emerging that astrocyte and neuronal primary cilia demonstrate a dichotomy in the mature mouse brain. However, it is unknown how astrocytic and neuronal primary cilia change their morphology and ciliary proteins when exposed to reactive insults including epilepsy and traumatic brain injury. We used a double transgenic mouse strain (Arl13b-mCherry; Centrin2-GFP), in which we found spontaneous seizures, and a cortical injury model to examine the morphological changes of astrocytic and neuronal primary cilia under reactive conditions. Transgenic overexpression of Arl13b drastically increases the length of astrocytic and neuronal primary cilia in the hippocampus, as well as the cilia lengths of cultured astrocytes and neurons. Spontaneous seizures shorten Arl13b-positive astrocytic cilia and AC3-positive neuronal cilia in the hippocampus. In a cortical injury model, Arl13b is not detectable in primary cilia, but Arl13b protein relocates to the cell body and has robust expression in the proximity of injured tissues. In contrast, the number of AC3-positive cilia near injured tissues remains unchanged, but their lengths become shorter. These results on astrocytic cilia implicate Arl13b in regulating astrocyte proliferation and tissue regeneration, while the shortening of AC3-positive cilia suggests adaptive changes of neuronal primary cilia under excitotoxicity.

Vascular smooth muscle TRPC3 channels facilitate the inverse hemodynamic response during status epilepticus

Human status epilepticus (SE) is associated with a pathological reduction in cerebral blood flow termed the inverse hemodynamic response (IHR). Canonical transient receptor potential 3 (TRPC3) channels are integral to the propagation of seizures in SE, and vascular smooth muscle cell (VSMC) TRPC3 channels participate in vasoconstriction. Therefore, we hypothesize that cerebrovascular TRPC3 channels may contribute to seizure-induced IHR. To examine this possibility, we developed a smooth muscle-specific TRPC3 knockout (TRPC3smcKO) mouse. To quantify changes in neurovascular coupling, we combined laser speckle contrast imaging with simultaneous electroencephalogram recordings. Control mice exhibited multiple IHRs, and a limited increase in cerebral blood flow during SE with a high degree of moment-to-moment variability in which blood flow was not correlated with neuronal activity. In contrast, TRPC3smcKO mice showed a greater increase in blood flow that was less variable and was positively correlated with neuronal activity. Genetic ablation of smooth muscle TRPC3 channels shortened the duration of SE by eliminating a secondary phase of intense seizures, which was evident in littermate controls. Our results are consistent with the idea that TRPC3 channels expressed by cerebral VSMCs contribute to the IHR during SE, which is a critical factor in the progression of SE.

SGK1.1 Reduces Kainic Acid-Induced Seizure Severity and Leads to Rapid Termination of Seizures

Approaches to control epilepsy, one of the most important idiopathic brain disorders, are of great importance for public health. We have previously shown that in sympathetic neurons the neuronal isoform of the serum and glucocorticoid-regulated kinase (SGK1.1) increases the M-current, a well-known target for seizure control. The effect of SGK1.1 activation on kainate-induced seizures and neuronal excitability was studied in transgenic mice that express a permanently active form of the kinase, using electroencephalogram recordings and electrophysiological measurements in hippocampal brain slices. Our results demonstrate that SGK1.1 activation leads to reduced seizure severity and lower mortality rates following status epilepticus, in an M-current–dependent manner. EEG is characterized by reduced number, shorter duration, and early termination of kainate-induced seizures in the hippocampus and cortex. Hippocampal neurons show decreased excitability associated to increased M-current, without altering basal synaptic transmission or other neuronal properties. Altogether, our results reveal a novel and selective anticonvulsant pathway that promptly terminates seizures, suggesting that SGK1.1 activation can be a potent factor to secure the brain against permanent neuronal damage associated to epilepsy.

Neuronal protective effect of Songling Xuemaikang capsules alone and in combination with carbamazepine on epilepsy in kainic acid-kindled rats

CONTEXT

Epilepsy is a common life-threatening neurological disorder that is often drug-resistant and associated with cognitive impairment. The traditional Chinese patent medicine Songling Xuemaikang capsules (SXC) is clinically used for epilepsy therapy and alleviation of cognitive impairment.

OBJECTIVE

This study investigates the neuronal protective effect of SXC combined with carbamazepine (CBZ) on epilepsy and cognitive impairment in kainic acid-kindled SD rats.

MATERIALS AND METHODS

Kainic acid-kindled rats were established by injection of 0.45 μg kainic acid and randomly divided into 5 groups (n = 14): saline (sham-operated), control, CBZ, SXC and CBZ + SXC combined group. Rats in the treatment groups received CBZ (50 mg/kg/d), SXC (600 mg/kg/d) or combined CBZ (50 mg/kg/d) + SXC (600 mg/kg/d) via intragastric injection for 60 days. Epileptic behaviours, cognitive impairment, neuronal apoptosis and expression of p-Akt, Akt and caspase-9 were measured, and the alleviation of cognitive damage and neuronal apoptosis was analyzed.

RESULTS

The combined administration of SXC and CBZ significantly decreased the frequency of seizures (1.2 ± 0.3) and the number of episodes (1.3 ± 0.5) above stage III (p < 0.05). Neuronal apoptosis was improved (p < 0.01), and cognitive damage was ameliorated (p < 0.05).The level of p-Akt was enhanced (p < 0.01) whereas the expression of caspase-9 was evidently inhibited (p < 0.01) in the combined group.

CONCLUSIONS

The present findings confirm that the combined use of SXC with CBZ can effectively control epileptic seizures, alleviate damage to hippocampal neurons and protect against cognitive impairment. The mechanism of action might be related to the upregulation of p-Akt and inhibition of caspase-9 expression.

Systemic thrombin inhibition ameliorates seizures in a mouse model of pilocarpine-induced status epilepticus

Status epilepticus (SE) is a life-threatening condition characterized by ongoing seizure activity which can lead to severe brain damage and death if not treated properly. Recent work suggests that alterations in blood-brain barrier (BBB) function and subsequent cortical exposure to coagulation factors may initiate, promote, and/or sustain SE. This suggestion is based on the observation that the serine protease thrombin, which plays a fundamental role in the blood coagulation cascade, increases neural excitability through the activation of protease-activated receptor 1 (PAR1). However, it remains unclear whether systemic inhibition of thrombin asserts "anti-epileptic" effects in vivo. We here used the pilocarpine model of SE in adult 3-month-old male mice to address the question whether intraperitoneal injection of the thrombin inhibitor α-NAPAP (0.75 mg/kg) counters SE. Indeed, pharmacological inhibition of thrombin ameliorates the behavioral outcome of pilocarpine-induced SE. Similar results are obtained when the thrombin receptor PAR1 is pharmacologically blocked using intraperitoneal injection of SCH79797 (25 μg/kg) prior to SE induction. Consistent with these results, an increase in thrombin immunofluorescence is detected in the hippocampus of pilocarpine-treated animals. Moreover, increased hippocampal serine protease activity is detected 90 min after SE induction, which is not observed in animals treated with α-NAPAP prior to SE induction. Together, these results corroborate and extend recent studies suggesting that novel oral anticoagulants which target thrombin (and PAR1) may assert anti-epileptic effects in vivo. KEY MESSAGES: Systemic thrombin/PAR1-inhibition ameliorates anticoagulants behavioral seizures. Status epilepticus increases thrombin levels in the hippocampus. Increased serine protease activity in the hippocampus after status epileptic. Anti-epileptic potential of clinically used anticoagulants must be evaluated.

5-Fluorouracil exacerbates cefepime-induced convulsions in pentylenetetrazol-kindled mice

OBJECTIVE

The antibiotics cefepime and meropenem are recommended for the treatment of neutropenia. However, cefepime has been found to be associated with both peripheral and central adverse events such as renal impairment and seizures, respectively. Previous studies showed that cefepime exacerbated convulsions in corneal kindled mouse models of epilepsy. However, its involvement in chemotherapy-induced side effects is unknown.

METHODS

In this study, we examined the convulsive potential of cefepime (500 mg/kg) and meropenem (500 mg/kg) in pentylenetetrazol (PTZ)-kindled mice using an electroconvulsive shock test with low-intensity stimulus currents. Then, the effects of 5-fluorouracil (5-FU, 200 and 400 mg/kg, i.p.) treatment, a model of chemotherapy-induced side effects, were investigated in the PTZ-kindled mouse model.

RESULTS

In fully PTZ-kindled mice, intravenous administration of cefepime (500 mg/kg) or meropenem (500 mg/kg) did not elicit any convulsions in the electroconvulsive shock test with low-intensity stimulus currents. In the PTZ-kindled mice treated with 5-FU (200 mg/kg), intravenous administration of cefepime (500 mg/kg) exacerbated the convulsions that occurred within 1 min in the electroconvulsive shock test, and the mice subsequently developed convulsive status epilepticus. However, intravenous administration of meropenem (500 mg/kg) did not produce such effects.

CONCLUSION

These findings suggest that the combination of 5-FU and cefepime exacerbates early-onset convulsive seizures and elicits delayed-onset convulsive status epilepticus. Additionally, 5-FU treatment increases the risk of induction of neurotoxic side effects by cefepime.

Adult neurogenesis in the mouse dentate gyrus protects the hippocampus from neuronal injury following severe seizures

Previous studies suggest that reducing the numbers of adult-born neurons in the dentate gyrus (DG) of the mouse increases susceptibility to severe continuous seizures (status epilepticus; SE) evoked by systemic injection of the convulsant kainic acid (KA). However, it was not clear if the results would be the same for other ways to induce seizures, or if SE-induced damage would be affected. Therefore, we used pilocarpine, which induces seizures by a different mechanism than KA. Also, we quantified hippocampal damage after SE. In addition, we used both loss-of-function and gain-of-function methods in adult mice. We hypothesized that after loss-of-function, mice would be more susceptible to pilocarpine-induced SE and SE-associated hippocampal damage, and after gain-of-function, mice would be more protected from SE and hippocampal damage after SE. For loss-of-function, adult neurogenesis was suppressed by pharmacogenetic deletion of dividing radial glial precursors. For gain-of-function, adult neurogenesis was increased by conditional deletion of pro-apoptotic gene Bax in Nestin-expressing progenitors. Fluoro-Jade C (FJ-C) was used to quantify neuronal injury and video-electroencephalography (video-EEG) was used to quantify SE. Pilocarpine-induced SE was longer in mice with reduced adult neurogenesis, SE had more power and neuronal damage was greater. Conversely, mice with increased adult-born neurons had shorter SE, SE had less power, and there was less neuronal damage. The results suggest that adult-born neurons exert protective effects against SE and SE-induced neuronal injury.

Synergistic action of CB1 and 5-HT2B receptors in preventing pilocarpine-induced status epilepticus in rats

Endocannabinoids (eCBs) and serotonin (5-HT) play a neuromodulatory role in the central nervous system. Both eCBs and 5-HT regulate neuronal excitability and their pharmacological potentiation has been shown to control seizures in pre-clinical and human studies. Compelling evidence indicates that eCB and 5-HT systems interact to modulate several physiological and pathological brain functions, such as food intake, pain, drug addiction, depression, and anxiety. Nevertheless, there is no evidence of an eCB/5-HT interaction in experimental and human epilepsies, including status epilepticus (SE). Here, we performed video-EEG recording in behaving rats treated with the pro-convulsant agent pilocarpine (PILO), in order to study the effect of the activation of CB₁/5-HT₂ receptors and their interaction on SE. Synthetic cannabinoid agonist WIN55,212-2 (WIN) decreased behavioral seizure severity of PILO-induced SE at 2 mg/kg (but not at 1 and 5 mg/kg, i.p.), while 5-HT_2B/2C receptor agonist RO60-0175 (RO; 1, 3, 10 mg/kg, i.p.) was devoid of any effect. RO 3 mg/kg was instead capable of potentiating the effect of WIN 2 mg/kg on the Racine scale score. Surprisingly, neither WIN 2 mg/kg nor RO 3 mg/kg had any effect on the incidence and the intensity of EEG seizures when administered alone. However, WIN+RO co-administration reduced the incidence and the severity of EEG SE and increased the latency to SE onset after PILO injection. WIN+RO effects were blocked by the selective CB₁R antagonist AM251 and the 5-HT_2BR antagonist RS127445, but not by the 5-HT_2CR antagonist SB242084 or the 5-HT_2AR antagonist MDL11,939. These data revealed a synergistic interaction between CB₁R/5-HT_2BR in the expression of PILO-induced SE.

Transgenic overexpression of furin increases epileptic susceptibility

The proprotein convertase Furin plays crucial roles in the pathology of many diseases. However, the specific role of furin in epilepsy remains unclear. In our study, furin protein was increased in the temporal neocortex of epileptic patients and in the hippocampus and cortex of epileptic mice. The furin transgenic (TG) mice showed increased susceptibility to epilepsy and heightened epileptic activity compared with wild-type (WT) mice. Conversely, lentivirus-mediated knockdown of furin restrained epileptic activity. Using whole-cell patch clamp, furin knockdown and overexpression influenced neuronal inhibitory by regulating postsynaptic gamma-aminobutyric acid A receptor (GABA_AR)-mediated synaptic transmission. Importantly, furin influenced the expression of GABA_AR β2/3 membrane and total protein in epileptic mice by changing transcription level of GABA_AR β2/3, not the protein degradation. These results reveal that furin may regulate GABA_AR-mediated inhibitory synaptic transmission by altering the transcription of GABA_AR β2/3 subunits in epilepsy; this finding could provide new insight into epilepsy prevention and treatment.

Ectopic expression of Miro 1 ameliorates seizures and inhibits hippocampal neurodegeneration in a mouse model of pilocarpine epilepsy

Epilepsy is a common disease of the central nervous system. This study aimed to investigate the role of mitochondrial Rho (Miro) 1 in epilepsy, using a mouse model of pilocarpine-induced status epilepticus (SE). Intraperitoneal injection of pilocarpine induced epileptic seizures in mice and significantly decreased Miro 1 expression in the hippocampus. Moreover, pilocarpine treatment increased the serum levels of heat shock protein 70 (HSP70) and S100 calcium binding protein B (S100B) and led to hippocampal neuronal injury and apoptosis. The intrinsic apoptotic pathway was activated in the hippocampal neurons following pilocarpine-induced SE, as evidenced by increased levels of cleaved caspase-3 and Bax, downregulation of Bcl-2, and the release of cytochrome c from mitochondria to cytoplasm. By contrast, forced expression of Miro 1 by lateral ventricular administration of adenovirus mitigated pilocarpine-induced epileptic seizures, reduced the elevation of HSP70 and S100B, and inhibited hippocampal neuronal apoptosis by suppressing the intrinsic apoptotic pathway. In summary, our data demonstrates that ectopic expression of Miro 1 alleviated pilocarpine-induced SE and protected hippocampal neurons by inhibiting the intrinsic apoptotic pathway. These findings provide new insights into epileptic disorders and suggest a potential neuroprotective value of Miro 1 in the treatment of epilepsy.

Morin Prevents Granule Cell Dispersion and Neurotoxicity via Suppression of mTORC1 in a Kainic Acid-induced Seizure Model

An abnormal reorganization of the dentate gyrus and neurotoxic events are important phenotypes in the hippocampus of patients with temporal lobe epilepsy (TLE). The effects of morin, a bioflavonoid constituent of many herbs and fruits, on epileptic seizures have not yet been elucidated, though its beneficial effects, such as its anti-inflammatory and neuroprotective properties, are well-described in various neurodegenerative diseases. In the present study, we investigated whether treatment with morin hydrate (MH) can reduce the susceptibility to seizures, granule cell dispersion (GCD), mammalian target of rapamycin complex 1 (mTORC1) activity, and the increases in the levels of apoptotic molecules and inflammatory cytokines in the kainic acid (KA)-induced seizure mouse model. Our results showed that oral administration of MH could reduce susceptibility to seizures and lead to the inhibition of GCD and mTORC1 activity in the KA-treated hippocampus. Moreover, treatment with MH significantly reduced the increased levels of apoptotic signaling molecules and pro-inflammatory mediators in the KA-treated hippocampus compared with control mice, suggesting a neuroprotective role. Therefore, these results suggest that morin has a therapeutic potential against epilepsy through its abilities to inhibit GCD and neurotoxic events in the in vivo hippocampus.

Use of Diffusional Kurtosis Imaging and Dynamic Contrast-Enhanced MR Imaging to Predict Posttraumatic Epilepsy in Rabbits

BACKGROUND AND PURPOSE

Finding a reliable biomarker to thoroughly assess the brain structure changes in posttraumatic epilepsy is of great importance. Our aim was to explore the value of diffusional kurtosis imaging combined with dynamic contrast-enhanced MR imaging in the evaluation of posttraumatic epilepsy.

MATERIALS AND METHODS

A modified weight-drop device was used to induce traumatic brain injury. Rabbits were exposed to traumatic brain injury or sham injury. Diffusional kurtosis imaging and dynamic contrast-enhanced MR imaging were performed 1 day after injury. Posttraumatic epilepsy was investigated 3 months after injury. The traumatic brain injury group was further divided into 2 groups: the posttraumatic epilepsy and the non-posttraumatic epilepsy groups. Mean kurtosis and volume transfer coefficient values in the cortex, hippocampus, and thalamus were analyzed. After follow-up, the experimental animals were sacrificed for Nissl staining.

RESULTS

The posttraumatic epilepsy group comprised 8 rabbits. In the ipsilateral cortex, the volume transfer coefficient in the traumatic brain injury group was higher than that in the sham group; the volume transfer coefficient in the posttraumatic epilepsy group was higher than that in the non-posttraumatic epilepsy group. In the ipsilateral hippocampus, the volume transfer coefficient in the posttraumatic epilepsy group was higher than that in the non-posttraumatic epilepsy and sham groups. No difference was observed between the non-posttraumatic epilepsy and sham groups. In the ipsilateral cortex, mean kurtosis in the traumatic brain injury group was lower than that in the sham group, and mean kurtosis in the posttraumatic epilepsy group was lower than that in the non-posttraumatic epilepsy group. In the ipsilateral thalamus and hippocampus, mean kurtosis in the traumatic brain injury group was lower than that in the sham group, and mean kurtosis in the posttraumatic epilepsy group was lower than that in the non-posttraumatic epilepsy group. In the contralateral thalamus, mean kurtosis in the traumatic brain injury group was lower than that in the sham group; however, no difference was observed between the posttraumatic epilepsy and non-posttraumatic epilepsy groups.

CONCLUSIONS

Diffusional kurtosis imaging and dynamic contrast-enhanced MR imaging could be used to predict the occurrence of posttraumatic epilepsy in rabbits exposed to experimental traumatic brain injury.

Status Epilepticus: Behavioral and Electroencephalography Seizure Correlates in Kainate Experimental Models

Various etiological factors, such as head injury, chemical intoxication, tumors, and gene mutation, can induce epileptogenesis. In animal models, status epilepticus (SE) triggers epileptogenesis. In humans, convulsive SE for >30 min can be a life-threatening medical emergency. The duration and severity of convulsive SE are highly variable in chemoconvulsant animal models. A continuous video-electroencephalography (EEG) recording, and/or diligent direct observation, facilitates quantification of exact duration of different stages of convulsive seizures (Racine stages 3–5) to determine the severity of SE. A continuous convulsive SE for >30 min usually causes high mortality in some rodents and results in widespread brain damage in the surviving animals, in spite of treating with antiepileptic drugs (AEDs). AEDs control behavioral seizures but not EEG seizures. The severity of initial SE impacts epileptogenesis and cognitive function; therefore, quantitative assessment of behavioral SE and EEG in animal models will help to understand the impact of SE severity on epileptogenesis. There are several excellent reviews on experimental models of seizure/SE/epilepsy. This review focusses on the comparison of induction and characterization of behavioral SE and EEG correlates in mice and rats induced by kainate. We also discuss the advantages of repeated low dose of kainate (i.p. route), which minimizes variability in the initial SE severity between animals and reduces mortality rate. A refined approach to induce SE with kainate also addresses the two of the 3Rs (i.e., refinement and reduction), the guiding principles for ethical and scientific standpoint of animal research.

Anterior thalamic nuclei deep brain stimulation reduces disruption of the blood-brain barrier, albumin extravasation, inflammation and apoptosis in kainic acid-induced epileptic rats

Objective The therapeutic efficacy of anterior thalamic nuclei deep brain stimulation (ATN-DBS) against seizures has been largely accepted; however, the effects of ATN-DBS on disruption of the blood-brain barrier (BBB), albumin extravasation, inflammation and apoptosis still remain unclear. Methods Rats were distributed into four treatment groups: physiological saline (PS, N = 12), kainic acid (KA, N = 12), KA-sham-DBS (N = 12) and KA-DBS (N = 12). Seizures were monitored using video-electroencephalogram (EEG). One day after surgery, all rats were sacrificed. Then, samples were prepared for quantitative real-time PCR (qPCR), western blot, immunofluorescence (IF) staining, and transmission electron microscopy to evaluate the disruption of the BBB, albumin extravasation, inflammation, and apoptosis. Result Because of the KA injection, the disruption of the BBB, albumin extravasation, inflammation and apoptosis were more severe in the KA and the KA-sham-DBS groups compared to the PS group (all Ps < 0.05 or < 0.01). The ideal outcomes were observed in the KA-DBS group. ATN-DBS produced a 46.3% reduction in seizure frequency and alleviated the disruption of the BBB, albumin extravasation, inflammatory reaction and apoptosis in comparison to the KA-sham-DBS group (all Ps < 0.05 or < 0.01). Conclusion (1) Seizures can be reduced using ATN-DBS in the epileptogenic stage. (2) ATN-DBS can reduce the disruption of the BBB and albumin extravasation. (3) ATN-DBS has an anti-inflammatory effect in epileptic models.

Targeted Interneuron Ablation in the Mouse Hippocampus Can Cause Spontaneous Recurrent Seizures

The death of GABAergic interneurons has long been hypothesized to contribute to acquired epilepsy. These experiments tested the hypothesis that focal interneuron lesions cause acute seizures [i.e., status epilepticus (SE)] and/or chronic epilepsy [i.e., persistent spontaneous recurrent seizures (SRSs)]. To selectively ablate interneurons, Gad2-ires-Cre mice were injected unilaterally in the CA1 area of the dorsal hippocampus with an adeno-associated virus containing the diphtheria toxin receptor (DTR). Simultaneously, an electrode, connected to a miniature telemetry device, was positioned at the injection site for chronic recordings of local field potentials (LFPs). Two weeks after virus transfection, intraperitoneal injection of DT consistently caused focal, specific, and extensive ablation of interneurons. Long-term, continuous monitoring revealed that all mice with DT-induced interneuron lesions had SRSs. Seizures lasted tens of seconds and interseizure intervals were several hours (or days); therefore, these interneuron lesions did not induce SE. The SRSs occurred 3-5 d after DT treatment, which is the estimated time required for DT-induced cell death; therefore, induction of SRSs occurred without the latent period typical of acquired epilepsy. In five of six DT-treated mice, SRSs stopped within days, suggesting that the DT-induced interneuron lesions did not usually cause epilepsy. In one mouse, however, SRSs occurred for ≥34 d after interneuron ablation, similar to epilepsy after experimental SE. Sham control mice had no detectable seizures, confirming that the SRSs were due to ablation of interneurons. These data show that selective interneuron ablation consistently caused SRSs but not SE; and, at least under the conditions used here, interneuron lesions rarely led to persistent SRSs (i.e., epilepsy).

The Wistar Audiogenic Rat (WAR) strain and its contributions to epileptology and related comorbidities: History and perspectives

In the context of modeling epilepsy and neuropsychiatric comorbidities, we review the Wistar Audiogenic Rat (WAR), first introduced to the neuroscience international community more than 25years ago. The WAR strain is a genetically selected reflex model susceptible to audiogenic seizures (AS), acutely mimicking brainstem-dependent tonic-clonic seizures and chronically (by audiogenic kindling), temporal lobe epilepsy (TLE). Seminal neuroethological, electrophysiological, cellular, and molecular protocols support the WAR strain as a suitable and reliable animal model to study the complexity and emergent functions typical of epileptogenic networks. Furthermore, since epilepsy comorbidities have emerged as a hot topic in epilepsy research, we discuss the use of WARs in fields such as neuropsychiatry, memory and learning, neuroplasticity, neuroendocrinology, and cardio-respiratory autonomic regulation. Last, but not least, we propose that this strain be used in "omics" studies, as well as with the most advanced molecular and computational modeling techniques. Collectively, pioneering and recent findings reinforce the complexity associated with WAR alterations, consequent to the combination of their genetically-dependent background and seizure profile. To add to previous studies, we are currently developing more powerful behavioral, EEG, and molecular methods, combined with computational neuroscience/network modeling tools, to further increase the WAR strain's contributions to contemporary neuroscience in addition to increasing knowledge in a wide array of neuropsychiatric and other comorbidities, given shared neural networks. During the many years that the WAR strain has been studied, a constantly expanding network of multidisciplinary collaborators has generated a growing research and knowledge network. Our current and major wish is to make the WARs available internationally to share our knowledge and to facilitate the planning and execution of multi-institutional projects, eagerly needed to contribute to paradigm shifts in epileptology. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic".

Everolimus is better than rapamycin in attenuating neuroinflammation in kainic acid-induced seizures

Background

Microglia is responsible for neuroinflammation, which may aggravate brain injury in diseases like epilepsy. Mammalian target of rapamycin (mTOR) kinase is related to microglial activation with subsequent neuroinflammation. In the present study, rapamycin and everolimus, both as mTOR inhibitors, were investigated in models of kainic acid (KA)-induced seizure and lipopolysaccharide (LPS)-induced neuroinflammation.

Methods

In vitro, we treated BV2 cells with KA and LPS. In vivo, KA was used to induce seizures on postnatal day 25 in B6.129P-Cx3cr1^tm1Litt/J mice. Rapamycin and everolimus were evaluated in their modulation of neuroinflammation detected by real-time PCR, Western blotting, and immunostaining.

Results

Everolimus was significantly more effective than rapamycin in inhibiting iNOS and mTOR signaling pathways in both models of neuroinflammation (LPS) and seizure (KA). Everolimus significantly attenuated the mRNA expression of iNOS by LPS and nitrite production by KA and LPS than that by rapamycin. Only everolimus attenuated the mRNA expression of mTOR by LPS and KA treatment. In the present study, we also found that the modulation of mTOR under LPS and KA treatment was not mediated by Akt pathway but was primarily mediated by ERK phosphorylation, which was more significantly attenuated by everolimus. This inhibition of ERK phosphorylation and microglial activation in the hippocampus by everolimus was also confirmed in KA-treated mice.

Conclusions

Rapamycin and everolimus can block the activation of inflammation-related molecules and attenuated the microglial activation. Everolimus had better efficacy than rapamycin, possibly mediated by the inhibition of ERK phosphorylation. Taken together, mTOR inhibitor can be a potential pharmacological target of anti-inflammation and seizure treatment.