The clinical impact of new antiepileptic drugs after a decade of use in epilepsy

Madhuca indica oil-entrapped buoyant galactomannan hydrogel microspheres for controlling epileptic seizures

A stable Madhuca indica oil-in-water nanoemulsion (99-210 nm, zeta potential: > - 30 mV) was produced employing Tween 20 (surfactant) and Transcutol P (co-surfactant) (3:1). The nanoemulsion (oil: Smix = 3:7, 5:5, and 7:3) were subsequently incorporated into oxcarbazepine-loaded carboxymethylxanthan gum (DS = 1.23) dispersion. The hydrogel microspheres were formed using the ionic gelation process. Higher oil concentration had a considerable impact on particle size, drug entrapment efficiency, and buoyancy. The maximum 92 % drug entrapment efficiency was achieved with the microspheres having oil: Smix ratio 5:5. FESEM study revealed that the microspheres were spherical in shape and had an orange peel-like surface roughness. FTIR analysis revealed a hydrogen bonding interaction between drug and polymer. Thermal and x-ray examinations revealed the transformation of crystalline oxcarbazepine into an amorphous form. The microspheres had a buoyancy period of 7.5 h with corresponding release of around 83 % drug in 8 h in simulated stomach fluid, governed by supercase-II transport mechanism. In vivo neurobehavioral studies on PTZ-induced rats demonstrated that the microspheres outperformed drug suspension in terms of rotarod retention, number of crossings, and rearing activity in open field. Thus, Madhuca indica oil-in-water nanoemulsion-entrapped carboxymethyl xanthan gum microspheres appeared to be useful for monitoring oxcarbazepine release and managing epileptic seizures.

Perampanel add-on for drug-resistant focal epilepsy

BACKGROUND

Epilepsy is one of the most common neurological disorders. Approximately 30% of people with epilepsy are considered to be drug-resistant, and usually need treatment with a combination of other antiepileptic drugs. Perampanel is a newer antiepileptic drug that has been investigated as add-on therapy for drug-resistant focal epilepsy.

OBJECTIVES

To evaluate the benefits and harms of perampanel as add-on therapy for people with drug-resistant focal epilepsy.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 20 October 2022.

SELECTION CRITERIA

We included randomised controlled trials comparing add-on perampanel with placebo.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcome was 1. 50% or greater reduction in seizure frequency. Our secondary outcomes were 2. seizure freedom, 3. treatment withdrawal due to any reason, 4. treatment withdrawal due to adverse effects, and 5.

ADVERSE EFFECTS

We used an intention-to-treat population for all primary analyses. We presented the results as risk ratios (RR) with 95% confidence intervals (CIs), except for individual adverse effects, which we reported with 99% CIs to compensate for multiple testing. We used GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We included seven trials involving 2524 participants, all aged over 12 years. The trials were double-blind, randomised, placebo-controlled trials with treatment duration of 12 to 19 weeks. We assessed four trials at overall low risk of bias, and three trials at overall unclear risk of bias, due to risk of detection, reporting, and other biases. Compared with placebo, participants receiving perampanel were more likely to achieve a 50% or greater reduction in seizure frequency (RR 1.67, 95% CI 1.43 to 1.95; 7 trials, 2524 participants; high-certainty evidence). Compared to placebo, perampanel increased seizure freedom (RR 2.50, 95% CI 1.38 to 4.54; 5 trials, 2323 participants; low-certainty evidence) and treatment withdrawal (RR 1.30, 95% CI 1.03 to 1.63; 7 trials, 2524 participants; low-certainty evidence). Participants treated with perampanel were more likely to withdraw from treatment due to adverse effects compared to those receiving placebo (RR 2.36, 95% CI 1.59 to 3.51; 7 trials, 2524 participants; low-certainty evidence). A higher proportion of participants receiving perampanel reported one or more adverse effects when compared to participants who received placebo (RR 1.17, 95% CI 1.10 to 1.24; 7 trials, 2524 participants; high-certainty evidence). Compared with placebo, participants receiving perampanel were more likely to experience ataxia (RR 14.32, 99% CI 1.09 to 188.31; 2 trials, 1098 participants; low-certainty evidence), dizziness (RR 2.87, 99% CI 1.45 to 5.70; 7 trials, 2524 participants; low-certainty evidence), and somnolence (RR 1.76, 99% CI 1.02 to 3.04; 7 trials, 2524 participants). Subgroup analysis indicated that a larger proportion of participants who received perampanel at a dose of 4 mg/day (RR 1.38, 95% CI 1.05 to 1.83; 2 trials, 710 participants), 8 mg/day (RR 1.83, 95% CI 1.51 to 2.22; 4 trials, 1227 participants), or 12 mg/day (RR 2.38, 95% CI 1.86 to 3.04; 3 trials, 869 participants) achieved a 50% or greater reduction in seizure frequency compared to placebo; however, treatment with perampanel 12 mg/day also increased treatment withdrawal (RR 1.77, 95% CI 1.31 to 2.40; 3 trials, 869 participants).

AUTHORS' CONCLUSIONS

Add-on perampanel is effective at reducing seizure frequency and may be effective at maintaining seizure freedom for people with drug-resistant focal epilepsy. Although perampanel was well-tolerated, there was a higher proportion of treatment withdrawals with perampanel compared with placebo. Subgroup analysis suggested that 8 mg/day and 12 mg/day are the most efficacious perampanel doses; however, the use of 12 mg/day would likely increase the number of treatment withdrawals. Future research should focus on investigating the efficacy and tolerability of perampanel with longer-term follow-up, as well as exploring an optimal dose.

Emerging Promise of Phytochemicals in Ameliorating Neurological Disorders

BACKGROUND

The field of medicine and synthetic drug development have advanced rapidly over the past few decades. However, research on alternative medicine such as phytochemicals cannot be ignored. The main reason for prominent curiosity about phytochemicals stems from the belief that usage of natural compounds is safer and has lesser detrimental side effects.

OBJECTIVE

The aim of the present review was to discuss in detail with several phytochemicals that have been studied or are being studied in the context of various neurological disorders including depression, Alzheimer's disease, Huntington's disease and even neuroinflammatory disorders such as encephalitis.

METHODS

The potential role of phytochemicals in the treatment or management of symptoms associated with neurological disorders have been included in this article. All data included in this paper has been pooled from various databases including Google Scholar, PubMed, Science Direct, Springer and Wiley Online Library.

RESULTS

Phytochemicals have been widely studied for their therapeutic properties associated with neurological disorders. Using various experimental techniques for both in vivo and in vitro experiments, studies have shown that phytochemicals do have antioxidant, anti-inflammatory and neuroprotective activities which play major roles in the treatment of neurological diseases.

CONCLUSION

Even though there has been compelling evidence of the therapeutic role of phytochemicals, further research is still required to evaluate the safety and efficacy of these medicines. Using previously published papers as foundation for additional research such as preclinical studies and clinical trials, phytochemicals can become a safer alternative to synthetic drugs for treating a spectrum of neurological diseases.

Carisbamate add-on therapy for drug-resistant focal epilepsy

BACKGROUND

Epilepsy is one of the most common neurological disorders. Many people with epilepsy are drug-resistant and require add-on therapy, meaning that they concomitantly take multiple antiepileptic drugs. Carisbamate is a drug which is taken orally and inhibits voltage-gated sodium channels. Carisbamate may be useful for drug-resistant focal epilepsy.

OBJECTIVES

To evaluate the efficacy and tolerability of carisbamate when used as an add-on therapy for drug-resistant focal epilepsy.

SEARCH METHODS

We searched the following databases on 8 April 2021: Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid) 1946 to April 07, 2021. CRS Web includes randomised or quasi-randomised controlled trials from PubMed, Embase, ClinicalTrials.gov, WHO ICTRP, the Cochrane Central Register of Controlled Trials (CENTRAL), and the specialised registers of Cochrane review groups including Epilepsy. We also searched ongoing trials registers, checked reference lists, and contacted authors of the included trials.

SELECTION CRITERIA

Double-blind randomised controlled trials (RCTs) comparing carisbamate versus placebo or another antiepileptic drug, as add-on therapy for drug-resistant focal epilepsy. Trials could have a parallel-group or cross-over design.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the trials for inclusion, assessed trial quality, and extracted data. The primary outcome was 50% or greater reduction in seizure frequency (responder rate). The secondary outcomes were: seizure freedom, treatment withdrawal (for any reason and due to adverse events); adverse events, and quality of life. We analysed data using the Mantel-Haenszel statistical method and according to the intention-to-treat population. We presented results as risk ratios (RRs) with 95% confidence intervals (CIs).

MAIN RESULTS

We included four RCTs involving a total of 2211 participants. All four trials compared carisbamate with placebo for drug-resistant focal epilepsy. Participants in all trials were over 16 years of age and received at least one other antiepileptic drug concomitantly. We detected substantial risk of bias across the included trials. All four trials were at high risk of attrition bias due to the incomplete reporting of attrition and the high treatment withdrawal rates noted, especially with higher doses. All four trials also had unclear risk of detection bias, as they did not specify whether outcome assessors were blinded. Meta-analysis suggested that carisbamate produced a higher responder rate compared to placebo (RR 1.36, 95% CI 1.14 to 1.62; 4 studies; moderate-certainty evidence). More participants in the carsibamate group achieved seizure freedom (RR 2.43, 95% CI 0.84 to 7.03; 1 study); withdrew from treatment for any reason (RR 1.32, 95% CI 0.82 to 2.12; 4 studies); and withdrew from treatment due to adverse events (RR 1.80, 95% CI 0.78 to 4.17; 4 studies) than in the placebo group. However, the evidence for the three outcomes was very low-certainty. There was no difference between treatment groups for the proportion of participants experiencing at least one adverse event (RR 1.10, 95% CI 0.93 to 1.30; 2 studies; low-certainty evidence). More participants in the carisbamate group than in the placebo group developed dizziness (RR 2.06, 95% CI 1.23 to 3.44; 4 studies; very low-certainty evidence) and somnolence (RR 1.82, 95% CI 1.28 to 2.58; 4 studies; low-certainty evidence), but not fatigue (RR 1.11, 95% CI 0.73 to 1.68; 3 studies); headache (RR 1.13, 95% CI 0.92 to 1.38; 4 studies); or nausea (RR 1.19, 95% CI 0.81 to 1.75; 3 studies). None of the included trials reported quality of life.

AUTHORS' CONCLUSIONS

The results suggest that carisbamate may demonstrate efficacy and tolerability as an add-on therapy for drug-resistant focal epilepsy. Importantly, the evidence for all outcomes except responder rate was of low to very low certainty, therefore we are uncertain of the accuracy of the reported effects. The certainty of the evidence is limited by the significant risk of bias associated with the included studies, as well as the statistical heterogeneity detected for some outcomes. Consequently, it is difficult for these findings to inform clinical practice. The studies were all of short duration and only included adult study populations. There is a need for further RCTs with more clear methodology, long-term follow-up, more clinical outcomes, more seizure types, and a broader range of participants.

Treatment with the combination of clavulanic acid and valproic acid led to recovery of neuronal and behavioral deficits in an epilepsy rat model

Epilepsy, which is caused by abnormal neuronal firing in the brain, is a common neurological disease and affects motor and cognitive functions. Excessive levels of glutamate and insufficient levels of inhibitory GABA are involved in its pathophysiology. Valproic acid (Val), a GABAergic agonist, is one of the first-line antiepileptic drugs, but it shows many adverse side effects at the clinical dose. Clavulanic acid (CA), a β-lactamase inhibitor, has been demonstrated to increase glutamate transporter-1 expression. This study evaluated the effects of CA and Val in an epilepsy rat model. Male Wistar rats received intraperitoneal injections of pentylenetetrazol (PTZ, 35 mg/kg, every other day, IP, for 13 days) to induce kindling epilepsy. After four times of PTZ injection, rats received daily treatment with CA (1 or 10 mg/kg, IP), Val (50 or 100 mg/kg, IP), or the combination of CA (1 mg/kg) and Val (50 mg/kg) for 7 consecutive days. Motor, learning, and memory functions were measured. Rats with PTZ-induced kindling exhibited seizures, motor dysfunction, cognitive impairment, and cell loss and reduction of neurogenesis in the hippocampus. Neither 1 mg/kg CA nor 50 mg/kg Val treatment was effective in alleviating behavioral and neuronal deficits. However, treatment with 10 mg/kg CA, 100 mg/kg Val, and the combination of 1 mg/kg CA and 50 mg/kg Val improved these behavioral and neuronal deficits. Particularly, the combination of CA and Val showed synergistic effects on seizure suppression, suggesting the potential for treating epilepsy and related neuronal damage and motor and cognitive deficits.

Baicalin Rescues Cognitive Dysfunction, Mitigates Neurodegeneration, and Exerts Anti-Epileptic Effects Through Activating TLR4/MYD88/Caspase-3 Pathway in Rats

Purpose

This study aims to evaluate the beneficial effects of anti-epileptic mechanisms of baicalin (BA) on cognitive dysfunction and neurodegeneration in pentylenetetrazol (PTZ)-induced epileptic rats.

Methods

First, PTZ-induced epileptic rats were administered intraperitoneally a sub-convulsive dose of PTZ (40 mg/kg) daily, and the seizure susceptibility (the degree of seizures and latency) was evaluated using Racine’s criterion. Then, classical behavioral experiments were performed to test whether BA ameliorated cognitive dysfunction. Neurodegeneration was assessed using Fluoro Jade-B (FJB), and NeuN staining was used to determine whether BA offered a neuroprotective role. After BA had been proven to possess anti-epileptic effects, its possible mechanisms were analyzed through network pharmacology. Finally, the key targets for predictive mechanisms were experimentally verified.

Results

The epileptic model was successfully established, and BA had anti-epileptic effects. Epileptic rats displayed significant cognitive dysfunction, and BA markedly ameliorated cognitive dysfunction. Further, we also discovered that BA treatment mitigated neurodegeneration of the hippocampus CA3 regions, thereby ameliorated cognitive dysfunction of epileptic rats. Subsequent network pharmacology analysis was implemented to reveal a possible mechanism of BA in the anti-epileptic process and the TLR4/MYD88/Caspase-3 pathway was predicted. Finally, experimental studies showed that BA exerted an anti-epileptic effect by activating the TLR4/MYD88/Caspase-3 pathway in PTZ-induced epileptic rats.

Conclusion

In conclusion, BA had a protective effect against PTZ-induced seizures. BA improved cognitive dysfunction and exerted a neuroprotective action. The anti-epileptic effects of BA may be potentially through activation of the TLR4/MYD88/Caspase-3 pathway.

Treatment effects of the combination of ceftriaxone and valproic acid on neuronal and behavioural functions in a rat model of epilepsy

NEW FINDINGS

What is the central question of this study? Imbalance of activities between GABAergic and glutamatergic systems is involved in epilepsy. It is not known whether simultaneously increasing GABAergic and decreasing glutamatergic activity using valproic acid and ceftriaxone, respectively, leads to better seizure control. What is the central question of this study? Ceftriaxone suppressed seizure and cognitive deficits and restored neuronal density and the number of newborn cells in the hippocampus in a rat model of epilepsy. Combined treatment with ceftriaxone and valproic acid showed additive effects in seizure suppression.

ABSTRACT

The pathophysiology of epilepsy is typically considered as an imbalance between inhibitory GABA and excitatory glutamate neurotransmission. Valproic acid (Val), a GABA agonist, is one of the first-line antiepileptic drugs in the treatment of epilepsy, but it exhibits adverse effects. Ceftriaxone (CEF) elevates expression of glutamate transporter-1, enhances the reuptake of synaptic glutamate, increases the number of newborn cells and exhibits neuroprotective effects in animal studies. In this study, we evaluated effects of the combination of CEF and Val on behavioural and neuronal measures in a rat epilepsy model. Male Wistar rats were injected i.p. with pentylenetetrazol (35 mg/kg, every other day for 13 days) to induce the epilepsy model. Ceftriaxone (10 or 50 mg/kg), Val (50 or 100 mg/kg) or the combination of CEF and Val were injected daily after the fourth pentylenetetrazol injection for seven consecutive days. Epileptic rats exhibited seizure and impairments in motor and cognitive functions. Treatment with CEF and Val reduced the seizure and enhanced motor and cognitive functions in a dose-dependent manner. The combination of CEF (10 mg/kg) and Val (50 mg/kg) improved behaviours considerably. Histologically, compared with control animals, epileptic rats exhibited lower neuronal density and a reduction in hippocampal newborn cells but higher apoptosis in the basolateral amygdala, all of which were restored by the treatment with CEF, Val or the combination of CEF and Val. The study findings demonstrated that the combination of low doses of CEF and Val has beneficial effects on seizure suppression, neuroprotection and improvement in motor and cognitive functions in epilepsy.

Combined use of the ketogenic diet and vagus nerve stimulation in pediatric drug-resistant epilepsy

Objective

Patients with drug-resistant epilepsy (DRE) pose considerable management challenges for patients, their families, and providers. Both the vagus nerve stimulator (VNS) and the ketogenic diet (KD) have been shown to be safe and effective in treating DRE. Nevertheless, information is lacking regarding treatment with combination of both modalities. This study reports the efficacy and tolerability of combining VNS and KD in a pediatric cohort with intractable epilepsy.

Methods

This is a retrospective review of 33 patients (0-17 years) with DRE treated with VNS and KD at a single pediatric level IV epilepsy center. We compared seizure reduction rates for each patient at baseline and at every clinic visit for 24 months after adding the second nonpharmacological therapy. The frequency of adverse events on the combined therapy was collected to assess safety and tolerability.

Results

There were a total of 170 visits for all patients while on the combined therapy. At 88% (95% CI: 83%-93%) of the visits, patients reported some reduction in seizure frequency. The proportion of patients reporting a greater than 50% seizure reduction over all visits was 62% (95% CI: 55%-69%). The proportion of a patient's visits with at least a greater than 50% reduction in seizure frequency had a median of 71% (IQR 33%-100%). Continued improvement was seen over time of combined treatment; for every one-unit time unit change (one month), there was a 6% increase in the odds of having a reduction in seizure frequency of >50% (OR = 1.06, 95% CI: 1.01-1.11).

Significance

This study shows that combining the VNS and KD in patients with drug-resistant epilepsy is well tolerated and reduces seizure frequency more than either one modality used alone and that the benefits in terms of seizure reduction continue to increase with the length of treatment.

Ketogenic diets for drug-resistant epilepsy

BACKGROUND

Ketogenic diets (KDs) are high in fat and low in carbohydrates and have been suggested to reduce seizure frequency in people with epilepsy. Such diets may be beneficial for children with drug-resistant epilepsy. This is an update of a review first published in 2003, and last updated in 2018.

OBJECTIVES

To assess the effects of ketogenic diets for people with drug-resistant epilepsy.

SEARCH METHODS

For this update, we searched the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid, 1946 to 26 April 2019) on 29 April 2019. The Cochrane Register of Studies includes the Cochrane Epilepsy Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), and randomised controlled trials (RCTs) from Embase, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We imposed no language restrictions. We checked the reference lists of retrieved studies for additional relevant studies.

SELECTION CRITERIA

RCTs or quasi-RCTs of KDs for people of any age with drug-resistant epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied predefined criteria to extract data and evaluated study quality. We assessed the outcomes: seizure freedom, seizure reduction (50% or greater reduction in seizure frequency), adverse effects, cognition and behaviour, quality of life, and attrition rate. We incorporated a meta-analysis. We utilised an intention-to-treat (ITT) population for all primary analyses. We presented the results as risk ratios (RRs) with 95% confidence intervals (CIs).

MAIN RESULTS

We identified 13 studies with 932 participants; 711 children (4 months to 18 years) and 221 adults (16 years and over). We assessed all 13 studies to be at high risk of performance and detection bias, due to lack of blinding. Assessments varied from low to high risk of bias for all other domains. We rated the evidence for all outcomes as low to very low certainty. Ketogenic diets versus usual care for children Seizure freedom (RR 3.16, 95% CI 1.20 to 8.35; P = 0.02; 4 studies, 385 participants; very low-certainty evidence) and seizure reduction (RR 5.80, 95% CI 3.48 to 9.65; P < 0.001; 4 studies, 385 participants; low-certainty evidence) favoured KDs (including: classic KD, medium-chain triglyceride (MCT) KD combined, MCT KD only, simplified modified Atkins diet (MAD) compared to usual care for children. We are not confident that these estimated effects are accurate. The most commonly reported adverse effects were vomiting, constipation and diarrhoea for both the intervention and usual care group, but the true effect could be substantially different (low-certainty evidence). Ketogenic diet versus usual care for adults In adults, no participants experienced seizure freedom. Seizure reduction favoured KDs (MAD only) over usual care but, again, we are not confident that the effect estimated is accurate (RR 5.03, 95% CI 0.26 to 97.68; P = 0.29; 2 studies, 141 participants; very low-certainty evidence). Adults receiving MAD most commonly reported vomiting, constipation and diarrhoea (very low-certainty evidence). One study reported a reduction in body mass index (BMI) plus increased cholesterol in the MAD group. The other reported weight loss. The true effect could be substantially different to that reported. Ketogenic diet versus ketogenic diet for children Up to 55% of children achieved seizure freedom with a classical 4:1 KD after three months whilst up to 85% of children achieved seizure reduction (very low-certainty evidence). One trial reported a greater incidence of seizure reduction with gradual-onset KD, as opposed to fasting-onset KD. Up to 25% of children were seizure free with MAD and up to 60% achieved seizure reduction. Up to 25% of children became seizure free with MAD and up to 60% experienced seizure reduction. One study used a simplified MAD (sMAD) and reported that 15% of children gained seizure freedom rates and 56% achieved seizure reduction. We judged all the evidence described as very low certainty, thus we are very unsure whether the results are accurate. The most commonly reported adverse effects were vomiting, constipation and diarrhoea (5 studies, very low-certainty evidence). Two studies reported weight loss. One stated that weight loss and gastrointestinal disturbances were more frequent, with 4:1 versus 3:1 KD, whilst one reported no difference in weight loss with 20 mg/d versus 10 mg/d carbohydrates. In one study, there was a higher incidence of hypercalcuria amongst children receiving classic KD compared to MAD. All effects described are unlikely to be accurate. Ketogenic diet versus ketogenic diet for adults One study randomised 80 adults (aged 18 years and over) to either MAD plus KetoCal during the first month with MAD alone for the second month, or MAD alone for the first month followed by MAD plus KetoCal for the second month. No adults achieved seizure freedom. More adults achieved seizure reduction at one month with MAD alone (42.5%) compared to MAD plus KetoCal (32.5%), however, by three months only 10% of adults in both groups maintained seizure reduction. The evidence for both outcomes was of very low certainty; we are very uncertain whether the effects are accurate. Constipation was more frequently reported in the MAD plus KetoCal group (17.5%) compared to the MAD only group (5%) (1 study, very low-certainty evidence). Diarrhoea and increase/change in seizure pattern/semiology were also commonly reported (17.5% to 20% of participants). The true effects of the diets could be substantially different to that reported.

AUTHORS' CONCLUSIONS

The evidence suggests that KDs could demonstrate effectiveness in children with drug-resistant epilepsy, however, the evidence for the use of KDs in adults remains uncertain. We identified a limited number of studies which all had small sample sizes. Due to the associated risk of bias and imprecision caused by small study populations, the evidence for the use of KDs was of low to very low certainty. More palatable but related diets, such as the MAD, may have a similar effect on seizure control as the classical KD, but could be associated with fewer adverse effects. This assumption requires more investigation. For people who have drug-resistant epilepsy or who are unsuitable for surgical intervention, KDs remain a valid option. Further research is required, particularly for adults with drug-resistant epilepsy.

Anticonvulsant and Neuroprotective Effects of Paeonol in Epileptic Rats

Paeonol is the main active compound in the root bark extract of the peony tree, and it has antioxidative and anti-inflammatory effects. Recent studies have reported the neuroprotective effects of paeonol including its capacity in improving impaired memory. However, the effect of paeonol on epilepsy is yet to be demystified. We aimed to investigate the therapeutic effect of paeonol in epilepsy and its relationship with oxidative stress damage and neuronal loss in the rat brain to reveal the underlying mechanisms of epileptic seizures. A rat model for chronic epilepsy was established, and the seizure scores of the rats in different groups were recorded. The seizure duration and the seizure onset latency were used to evaluate the anticonvulsant effects of paeonol. Terminal deoxynucleotidyl transferase dUTP nick end-labeling staining, Nissl staining and H/E staining were used to evaluate the effects of paeonol on neuronal loss and apoptosis in epileptic rats. The colorimetric assessment of malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, catalase activity and total antioxidant capacity of paeonol were used in assessing paeonol's effect on oxidative stress in epileptic rats. Evaluation of Caspase-3 mRNA and protein expression levels were determined using western blot and quantitative real-time (RT-q)PCR. In this study, we found that paeonol reduced the seizure scores of epileptic rats and attenuated the duration and onset latency of seizures. Paeonol can also increase the activities of total antioxidant capacity, SOD and catalase activity and reduce MDA content as well. This suggests that paeonol can improve the level of oxidative stress in rats. More significantly, paeonol can improve neuronal loss and apoptosis in epileptic rats. These results indicate that paeonol has anticonvulsant and neuroprotective effects in epileptic rats. This effect may be caused by reducing oxidative stress.

Clinical opinion: Earlier employment of polytherapy in sequential pharmacotherapy of epilepsy

Modern pharmacotherapy for epilepsy consists of orderly, sequential drug trials, in which antiepileptic drugs (AEDs) are chosen under the concept of individual patient-oriented (or - tailored) pharmacotherapy. Although monotherapy has been established as the preferred mode of AEDs therapy in both newly diagnosed and drug resistant epilepsies, there are still lack of evidence to favor either monotherapy or polytherapy in epilepsy, which has generated continuing controversies on the preferred mode of pharmacotherapy. However, each mode of pharmacotherapy may have both advantages and disadvantages, which are different and variable related to individual case scenario. We conducted a brief comparative overview between monotherapy and polytherapy to provide clues for earlier employment of polytherapy in each steps of sequential drug trials. Previous claims about the advantages of monotherapy over polytherapy are not supported but gradually losing its ground by the introduction of a large number of drugs carrying pharmacological advantages for combination therapy. Current evidence stresses the importance of combining drugs having synergistic interactions for better outcome of polytherapy, which has not been considered in previous clinical investigations comparing monotherapy and polytherapy. It is likely that a significant improvement in the outcome of current AEDs therapy is feasible by earlier employment of polytherapy as well as identification of combination drug regimens carrying synergistic interactions. At present, lamotrigine(LTG) and valproate(VPA) combination regimen is the only well documented synergistic regimen, but there are a long-list of candidate regimens requiring future trials in appropriate designs.

Ketogenic diets for drug-resistant epilepsy

BACKGROUND

Ketogenic diets (KDs), being high in fat and low in carbohydrates, have been suggested to reduce seizure frequency in people with epilepsy. At present, such diets are mainly recommended for children who continue to have seizures despite treatment with antiepileptic drugs (AEDs) (drug-resistant epilepsy). Recently, there has been interest in less restrictive KDs, including the modified Atkins diet (MAD), and the use of these diets has extended into adult practice. This is an update of a review first published in 2003 and last updated in 2016.

OBJECTIVES

To assess the effects of KDs for drug-resistant epilepsy by reviewing the evidence from randomised controlled trials.

SEARCH METHODS

For the latest update we searched the Cochrane Epilepsy Group's Specialized Register (11 April 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO, 11 April 2017), MEDLINE (Ovid, 11 April 2017), ClinicalTrials.gov (11 April 2017) and the WHO International Clinical Trials Registry Platform (ICTRP, 11 April 2017). We imposed no language restrictions. We checked the reference lists of retrieved studies for additional reports of relevant studies.

SELECTION CRITERIA

Randomised controlled trials or quasi-randomised controlled trials of ketogenic diets for people with drug-resistant epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied predefined criteria to extract data and assessed study quality.

MAIN RESULTS

We identified 11 randomised controlled trials (RCTs) that generated 15 publications.All trials applied an intention-to-treat analysis with varied randomisation methods. The 11 studies recruited 778 patients; 712 children and adolescents and 66 adults. We assessed all 11 studies to be at low to unclear risk of bias for the following domains: random sequence generation, allocation concealment and selective reporting. For the other domains (blinding, incomplete outcome data, other bias) assessments were varied (low, unclear and high risk of bias). We could not conduct a meta-analysis due to the heterogeneity of the studies and the quality of the evidence was low to very low (GRADE ratings).Reported rates of seizure freedom reached as high as 55% in a classical 4:1 KD group after three months and reported rates of seizure reduction reached as high as 85% in a classical 4:1 KD group after three months (GRADE rating low).One trial found no significant difference between the fasting-onset and gradual-onset KD for rates of seizure freedom, and reported a greater rate of seizure reduction in the gradual-onset KD group.Studies assessing the efficacy of the MAD reported seizure freedom rates of up to 25% and seizure reduction rates of up to 60% in children. One study used a simplified MAD (sMAD) and reported seizure freedom rates of 15% and seizure reduction rates of 56% in children. One study utilised a MAD in adults and reported seizure reduction rates of 35%, but no patients became seizure free (GRADE rating low).Adverse effects of the dietary interventions were experienced in all studies. The most commonly reported adverse effects were gastrointestinal syndromes. It was common that adverse effects were the reason for participants dropping out of trials (GRADE rating low). Other reasons for dropout included lack of efficacy and non-acceptance of the diet (GRADE rating low).Although there was some evidence for greater antiepileptic efficacy for a classical 4:1 KD over lower ratios, the classical 4:1 KD was consistently associated with more adverse effects.One study assessed the effect of dietary interventions on quality of life, cognition and behavioural functioning, reporting participants in the KD group to be more active, more productive and less anxious after four months, compared to the control group. However, no significant difference was found in quality-adjusted life years (QALYs) between the KD group and control group at four or 16 months (GRADE rating very low).

AUTHORS' CONCLUSIONS

The RCTs discussed in this review show promising results for the use of KDs in epilepsy. However, the limited number of studies, small sample sizes and the limited studies in adults, resulted in a low to very low overall quality of evidence.There were adverse effects within all of the studies and for all KD variations, such as short-term gastrointestinal-related disturbances and increased cholesterol. However, study periods were short, therefore the long-term risks associated with these adverse effects is unknown. Attrition rates remained a problem with all KDs and across all studies; reasons for this being lack of observed efficacy and dietary tolerance.Only one study reported the use of KDs in adults with epilepsy; therefore further research would be of benefit.Other more palatable but related diets, such as the MAD, may have a similar effect on seizure control as the classical KD, but this assumption requires more investigation. For people who have medically intractable epilepsy or people who are not suitable for surgical intervention, KDs remain a valid option; however, further research is required.

Vagus nerve stimulation (VNS) therapy update

Epilepsy affects millions of people worldwide. Approximately one-third have pharmacoresistant epilepsy, and of these, the majority are not candidates for epilepsy surgery. Vagus nerve stimulation (VNS) therapy has been an option to treat pharmacoresistant seizures for 30 years. In this update, we will review the clinical data that support the device's efficacy in children, adolescents, and adults. We will also review its side-effect profile, quality of life and cost benefits, and the impact the device has on sudden unexpected death in epilepsy (SUDEP). We will then discuss candidate selection and provide guidance on dosing and future models. Vagus nerve stimulation therapy is an effective treatment for many seizure types and epilepsy syndromes with a predictable and benign side-effect profile that supports its role as the most commonly prescribed device to treat pharmacoresistant epilepsy. "This article is part of the Supplement issue Neurostimulation for Epilepsy."

Studies on Anticonvulsant Effects of Novel Histamine H3R Antagonists in Electrically and Chemically Induced Seizures in Rats

A newly developed series of non-imidazole histamine H3 receptor (H3R) antagonists (1⁻16) was evaluated in vivo for anticonvulsant effects in three different seizure models in Wistar rats. Among the novel H3R antagonists examined, H3R antagonist 4 shortened the duration of tonic hind limb extension (THLE) in a dose-dependent fashion in the maximal electroshock (MES)-induced seizure and offered full protection against pentylenetetrazole (PTZ)-induced generalized tonic-clonic seizure (GTCS), following acute systemic administration (2.5, 5, 10, and 15 mg/kg, i.p.). However, only H3R antagonist 13, without appreciable protective effects in MES- and PTZ-induced seizure, fully protected animals in the strychnine (STR)-induced GTCS following acute systemic pretreatment (10 mg/kg, i.p.). Moreover, the protective effect observed with H3R antagonist 4 in MES-induced seizure was completely abolished when animals were co-administered with the H3R agonist (R)-α-methylhistamine (RAMH, 10 mg/kg, i.p.). However, RAMH failed to abolish the full protection provided by the H3R antagonist 4 in PTZ-induced seizure and H3R antagonist 13 in STR-induced seizure. Furthermore, in vitro antiproliferative effects or possible metabolic interactions could not be observed for compound 4. Additionally, the predictive in silico, as well as in vitro, metabolic stability for the most promising H3R antagonist 4 was assessed. The obtained results show prospective effects of non-imidazole H3R antagonists as innovative antiepileptic drugs (AEDs) for potential single use against epilepsy.

Sinomenine exerts anticonvulsant profile and neuroprotective activity in pentylenetetrazole kindled rats: involvement of inhibition of NLRP1 inflammasome

Background

Epilepsy is a common neurological disorder and is not well controlled by available antiepileptic drugs (AEDs). Inflammation is considered to be a critical factor in the pathophysiology of epilepsy. Sinomenine (SN), a bioactive alkaloid with anti-inflammatory effect, exerts neuroprotective activity in many nervous system diseases. However, little is known about the effect of SN on epilepsy.

Methods

The chronic epilepsy model was established by pentylenetetrazole (PTZ) kindling. Morris water maze (MWM) was used to test spatial learning and memory ability. H.E. staining and Hoechst 33258 staining were used to evaluate hippocampal neuronal damage. The expression of nucleotide oligomerization domain (NOD)-like receptor protein 1 (NLRP1) inflammasome complexes and the level of inflammatory cytokines were determined by western blot, quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA) kits.

Results

SN (20, 40, and 80 mg/kg) dose-dependently disrupts the kindling acquisition process, which decreases the seizure scores and the incidence of fully kindling. SN also increases the latency of seizure and decreases the duration of seizure in fully kindled rats. In addition, different doses of SN block the hippocampal neuronal damage and minimize the impairment of spatial learning and memory in PTZ kindled rats. Finally, PTZ kindling increases the expression of NLRP1 inflammasome complexes and the levels of inflammatory cytokines IL-1β, IL-18, IL-6, and TNF-α, which are all attenuated by SN in a dose- dependent manner.

Conclusions

SN exerts anticonvulsant and neuroprotective activity in PTZ kindling model of epilepsy. Disrupting the kindling acquisition, which inhibits NLRP1 inflammasome-mediated inflammatory process, might be involved in its effects.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1199-0) contains supplementary material, which is available to authorized users.

Anticonvulsant evaluation of novel non-imidazole histamine H3R antagonists in different convulsion models in rats

Novel non-imidazole histamine H3 receptor (H3R) antagonists (2-8) were developed and assessed for in-vitro antagonist binding affinities at the human histamine H1-H4R. These novel H3R antagonists (2-8) were examined in-vivo for anticonvulsant effects in three different convulsion models in male adult rats. Compound 6 significantly and dose-dependently exhibited decreased duration of tonic hind limb extension (THLE) in the maximal electroshock (MES)- and fully protected animals against pentylenetetrazole (PTZ)-induced convulsion, following acute systemic administration (5, 10, and 20 mg/kg, i.p.). Contrary, all compounds 2-8 showed moderate protection in the strychnine (STR)-induced convulsion model following acute pretreatment (10 mg/kg, i.p.). Moreover, the acute systemic administration of H3R antagonist 6 (10 mg/kg, i.p.) significantly prolonged latency time for MES convulsions. Furthermore, the anticonvulsant effect observed with compound 6 in MES-model was entirely abrogated when rats were co-injected with the brain penetrant H1R antagonist pyrilamine (PYR) but not the brain penetrant H2R antagonist zolantidine (ZOL). However, PYR and ZOL failed to abolish the full protection provided by the H3R antagonist 6 in PTZ- and STR-models. No mutagenic or antiproliferative effects or potential metabolic interactions were shown for compound 6 when assessing its antiproliferative activities and metabolic profiling applying in-vitro methods. These findings demonstrate the potential of non-imidazole H3R antagonists as novel antiepileptic drugs (AEDs) either for single use or in addition to currently available epilepsy medications.

Assessment of luteolin isolated from Eclipta alba leaves in animal models of epilepsy

CONTEXT

Eclipta alba (Linn) Hassk. (Asteraceae) has been reported to be a nerve tonic and has been used to treat epilepsy in folk medicine.

OBJECTIVE

The present study isolates and characterizes luteolin from E. alba and evaluates its antiepileptic potential in chemically induced acute and chronic models in mice.

MATERIALS AND METHODS

The methanol extract (16.85% w/w) of E. alba leaves was subjected to fractionation for isolation of luteolin. In acute pentylenetetrazole (PTZ) model, luteolin (5, 10, 20 mg/kg, i.p.) was administered 30 min prior to PTZ injection (100 mg/kg) in Swiss albino mice. Kindling was induced by chronic administration of PTZ (35 mg/kg) on every alternate day (48 days). Luteolin was investigated on the course of kindling development and oxidative stress markers [reduced glutathione (GSH) and malondialdehyde (MDA)] in kindled mice.

RESULTS

Single-dose pretreatment with luteolin (10 and 20 mg/kg, i.p.) was found to be effective in an acute PTZ model (100% protection from mortality) and it did not exhibit any effect on motor coordination at the same doses. PTZ-induced kindling was significantly (p < 0.001) prevented by luteolin (5, 10, 20 mg/kg, i.p.) in a dose-dependent manner. Luteolin restored levels of reduced GSH (p < 0.001) and decreased the level of MDA (p < 0.001), a marker of lipid peroxidation.

DISCUSSION AND CONCLUSION

The results of the present study demonstrated that luteolin had an anticonvulsant effect in an acute PTZ model. Luteolin exhibited and inhibitory effect on the course of kindling and associated oxidative stress and hence could be a potential molecule in the treatment of epilepsy.

Anticonvulsant effects of isomeric nonimidazole histamine H3 receptor antagonists

Phenytoin (PHT), valproic acid, and modern antiepileptic drugs (AEDs), eg, remacemide, loreclezole, and safinamide, are only effective within a maximum of 70%–80% of epileptic patients, and in many cases the clinical use of AEDs is restricted by their side effects. Therefore, a continuous need remains to discover innovative chemical entities for the development of active and safer AEDs. Ligands targeting central histamine H₃ receptors (H₃Rs) for epilepsy might be a promising therapeutic approach. To determine the potential of H₃Rs ligands as new AEDs, we recently reported that no anticonvulsant effects were observed for the (S)-2-(4-(3-(piperidin-1-yl)propoxy)benzylamino)propanamide (1). In continuation of our research, we asked whether anticonvulsant differences in activities will be observed for its R-enantiomer, namely, (R)-2-(4-(3-(piperidin-1-yl)propoxy)benzylamino)propaneamide (2) and analogs thereof, in maximum electroshock (MES)-, pentylenetetrazole (PTZ)-, and strychnine (STR)-induced convulsion models in rats having PHT and valproic acid (VPA) as reference AEDs. Unlike the S-enantiomer (1), the results show that animals pretreated intraperitoneally (ip) with the R-enantiomer 2 (10 mg/kg) were moderately protected in MES and STR induced models, whereas proconvulsant effect was observed for the same ligand in PTZ-induced convulsion models. However, animals pretreated with intraperitoneal doses of 5, 10, or 15 mg/kg of structurally bulkier (R)-enantiomer (3), in which 3-piperidinopropan-1-ol in ligand 2 was replaced by (4-(3-(piperidin-1-yl)propoxy)phenyl)methanol, and its (S)-enantiomer (4) significantly and in a dose-dependent manner reduced convulsions or exhibited full protection in MES and PTZ convulsions model, respectively. Interestingly, the protective effects observed for the (R)-enantiomer (3) in MES model were significantly greater than those of the standard H₃R inverse agonist/antagonist pitolisant, comparable with those observed for PHT, and reversed when rats were pretreated with the selective H₃R agonist R-(α)-methyl-histamine. Comparisons of the observed antagonistic in vitro affinities among the ligands 1–6 revealed profound stereoselectivity at human H₃Rs with varying preferences for this receptor subtype. Moreover, the in vivo anticonvulsant effects observed in this study for ligands 1–6 showed stereoselectivity in different convulsion models in male adult rats.

Protective Effects of Otophylloside N on Pentylenetetrazol-Induced Neuronal Injury In vitro and In vivo

Approximately 30% of epileptic patients worldwide are medically unable to control their seizures. In addition, repeated epileptic seizures generally lead to neural damage. Pentylenetetrazol (PTZ) is a clinical circulatory and respiratory stimulant that is experimentally used to mimic epileptic convulsion in epilepsy research. Here, we systematically explore the neuroprotective effects of a pure compound isolated from Cynanchum otophyllum Schneid (Qingyangshen), Otophylloside N (OtoN), against PTZ-induced neuronal injury. We used three models: in vitro primary cortical neurons, in vivo mice, and in vivo zebrafish. Our results revealed that OtoN treatment may attenuate PTZ-induced morphology changes, cell death, LDH efflux in embryonic neuronal cells of C57BL/6J mice, and convulsive behavior in zebrafish. Additionally, our Western blot and RT-PCR results demonstrated that OtoN may attenuate PTZ-induced apoptosis and neuronal activation in neuronal cells, mice, and zebrafish. OtoN may reduce PTZ-induced cleavage of poly ADP-ribose polymerase and upregulation of the Bax/Bcl-2 ratio and decrease the expression level of c-Fos. This study is the first investigation of the neuroprotective effects of OtoN, which might be developed as a novel antiepileptic drug.

Histamine H3 receptor as a potential target for cognitive symptoms in neuropsychiatric diseases

The potential contributions of the brain histaminergic system in neurodegenerative diseases, and the possiblity of histamine-targeting treatments is attracting considerable interests. The histamine H3 receptor (H3R) is expressed mainly in the central nervous system, and is, consequently, an attractive pharmacological target. Although recently described clinical trials have been disappointing in attention deficit hyperactivity disorder (ADHD) and schizophrenia (SCH), numerous H3R antagonists, including pitolisant, demonstrate potential in the treatment of narcolepsy, excessive daytime sleepiness associated with cognitive impairment, epilepsy, and Alzheimer's disease (AD). This review focuses on the recent preclinical as well as clinical results that support the relevance of H3R antagonists for the treatment of cognitive symptoms in neuropsychiatric diseases, namely AD, epilepsy and SCH. The review summarizes the role of histaminergic neurotransmission with focus on these brain disorders, as well as the effects of numerous H3R antagonists on animal models and humans.

Ketogenic diet and other dietary treatments for epilepsy

BACKGROUND

The ketogenic diet (KD), being high in fat and low in carbohydrates, has been suggested to reduce seizure frequency. It is currently used mainly for children who continue to have seizures despite treatment with antiepileptic drugs. Recently, there has been interest in less restrictive KDs including the modified Atkins diet (MAD) and the use of these diets has extended into adult practice.

OBJECTIVES

To review the evidence for efficacy and tolerability from randomised controlled trials regarding the effects of KD and similar diets.

SEARCH METHODS

We searched the Cochrane Epilepsy Group's Specialized Register (30 March 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO, 30 March 2015), MEDLINE (Ovid, 30 March 2015), ClinicalTrials.gov (30 March 2015) and the WHO International Clinical Trials Registry Platform (ICTRP, 30 March 2015). We imposed no language restrictions. We checked the reference lists of retrieved studies for additional reports of relevant studies.

SELECTION CRITERIA

Studies of KDs and similar diets for people with epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied pre-defined criteria to extract data and assessed study quality.

MAIN RESULTS

We identified seven randomised controlled trials that generated eight publications.All trials applied an intention-to-treat analysis with varied randomisation methods. The seven studies recruited 427 children and adolescents and no adults. We could not conduct a meta-analysis due to the heterogeneity of the studies.Reported rates of seizure freedom reached as high as 55% in a 4 : 1 KD group after three months and reported rates of seizure reduction reached as high as 85% in a 4 : 1 KD group after three months.One trial found no significant difference between the fasting-onset and gradual-onset KD for rates of seizure freedom and reported a greater rate of seizure reduction in the gradual-onset KD group.Studies assessing the efficacy of the MAD reported seizure freedom rates of up to 10% and seizure reduction rates of up to 60%. One study compared the MAD to a 4 : 1 KD, but did not report rates of seizure freedom or seizure reduction.Adverse effects were fairly consistent across different dietary interventions. The most commonly reported adverse effects were gastrointestinal syndromes. It was common that adverse effects were the reason for participants dropping out of trials. Other reasons for drop-out included lack of efficacy and non-acceptance of the diet.Although there was some evidence for greater antiepileptic efficacy for a 4 : 1 KD over lower ratios, the 4 : 1 KD was consistently associated with more adverse effects.No studies assessed the effect of dietary interventions on quality of life, or cognitive or behavioural functioning.

AUTHORS' CONCLUSIONS

The randomised controlled trials discussed in this review show promising results for the use of KDs in epilepsy. However, the limited number of studies, small sample sizes and a sole paediatric population resulted in a poor overall quality of evidence.There were adverse effects within all of the studies and for all KD variations, such as short-term gastrointestinal-related disturbances, to longer-term cardiovascular complications. Attrition rates remained a problem with all KDs and across all studies, reasons for this being lack of observed efficacy and dietary tolerance.There was a lack of evidence to support the clinical use of KD in adults with epilepsy, therefore, further research would be of benefit.Other more palatable but related diets, such as the MAD ketogenic diet, may have a similar effect on seizure control as classical KD but this assumption requires more investigation. For people who have medically intractable epilepsy or people who are not suitable for surgical intervention, a KD remains a valid option; however, further research is required.

Anticonvulsant and procognitive properties of the non-imidazole histamine H3 receptor antagonist DL77 in male adult rats

It has become clear that histamine H3 receptors (H3Rs) are implicated in modulating epilepsy and memory in laboratory animals. The new non-imidazole H3R antagonist DL77 has excellent selectivity profile and shows high in-vivo potency as well as in-vitro antagonist affinity with ED50 values of 2.1 ± 0.2 mg/kg and 8.4 ± 1.3 [nM], respectively. In the present study, the anticonvulsant effects of DL77 on maximal electroshock (MES)-, pentylenetetrazole (PTZ)-, and strychnine (STR)-induced seizure models were investigated. Moreover, the procognitive properties of DL77 were tested on acquisition, consolidation and retrieval processes in a one-trial inhibitory avoidance task in male Wistar rats. The results indicate that DL77 (5, 10, and 15 mg/kg, i.p.) significantly and dose-dependently reduced MES-induced seizure duration, whereas no protection was observed in PTZ- or STR-induced seizures. Importantly, the protective action observed for DL77 in MES-induced seizure was comparable to that of the reference antiepileptic drug (AED) phenytoin (PHT), and was also reversed when rats were pretreated with the CNS penetrant pyrilamine (PYR) (10 mg/kg, i.p.), or with the selective H3R agonist R-(α)-methyl-histamine (RAMH) (10 mg/kg, i.p.). Furthermore, the procognitive studies indicate that acute pre-training systemic administration of DL77 (2.5 mg/kg, i.p.) facilitated acquisition, whereas pre-testing acute administration of DL77 (5 and 10 mg/kg, i.p.) improved retrieval. Interestingly, the procognitive effect of DL77 on retrieval was completely abrogated when rats were pretreated with the centrally-acting H2R antagonist zolantidine (ZOL) but not the centrally acting H1R antagonist PYR, indicating that histaminergic pathways through activation of H2Rs appear to be participating in neuronal circuits involved in retrieval processes. Taken together, our results show that DL77 demonstrates anticonvulsant properties in the MES-induced seizure model and improves cognitive performance through actions on different memory stages. Therefore, H3Rs may have implications for the treatment of degenerative disorders associated with impaired memory function and may represent a novel therapeutic pharmacological target to tackle cognitive problems associated with the chronic use of antiepileptic drugs. This article is part of the Special Issue entitled 'Histamine Receptors'.

Perampanel: expanding therapeutic options for patients with medically refractory secondary generalized convulsive seizures

To evaluate the efficacy of adjunctive, once-daily perampanel against secondarily generalized (SG) seizures in three Phase III trials (studies 304, 305, and 306) and their extension (study 307). The Phase III studies enrolled patients (≥ 12 years) with uncontrolled partial-onset seizures despite treatment with 1-3 concomitant antiepileptic drugs. Patients completing the core Phase III studies were eligible for the extension study. Endpoints included median percent change in SG seizure frequency, 50% responder (proportion of patients achieving a ≥ 50% reduction in SG seizure frequency), 75% response, and seizure-freedom rates. In total, 1480 patients were randomized and treated in the three perampanel Phase III trials. At baseline, 71.9% of placebo-treated and 68.4% of perampanel-treated patients had a history of SG seizures. In the individual core Phase III studies, perampanel (4-12 mg) reduced seizure frequency and improved responder rates. Consistent with this, in pooled analyses of the Phase III data, the median percent change in SG seizure frequency was -48.6%, -62.9%, and -53.3% with perampanel 4, 8, and 12 mg, respectively, vs -19.4% with placebo; 50% responder rates were 49.3%, 60.5%, and 53.7% vs 37.0% with placebo. More perampanel-treated patients had ≥ 75% reductions in SG seizure frequency, and seizure-freedom rates improved, compared with placebo. Improvements in seizure frequency and responder rate were maintained during the extension study. Perampanel consistently demonstrated efficacy against SG seizures when assessed using various endpoints. Furthermore, reductions in seizure frequency and improvements in responder rate were sustained with long-term perampanel treatment.

Root extract of Anacyclus pyrethrum ameliorates seizures, seizure-induced oxidative stress and cognitive impairment in experimental animals

In Ayurveda, Anacyclus pyrethrum has been used as a brain tonic. The present study evaluates the effect of hydroalcoholic extract of A. pyrethrum (HEAP) root against seizures, seizure-induced oxidative stress and cognitive impairment in experimental models of seizures. Male Wistar rats were used in the study. HEAP was administered in doses of 50, 100, 250, 500 in pentylenetetrazole (PTZ) model and 250, 500 and 1000 mg/kg in maximal electroshock (MES) model. Myoclonic jerk latency and generalized tonic clonic seizures (GTCS) were noted in PTZ whereas occurrence of tonic hind limb extension (THLE) was observed in MES seizures. Cognitive deficit was assessed using elevated plus maze and passive avoidance tests. Whole brain reduced glutathione, malondialdehyde levels and cholinesterase activity were measured. HEAP showed 50, 66.7, 83.3 and 100% protection at 50,100, 250 and 500 mg/kg, respectively against GTCS in PTZ induced seizures. In MES induced seizures, HEAP produced 16.7, 33.3 and 50% protection against THLE at 250, 500 and 1000 mg/kg, respectively. HEAP administration significantly prevented seizure induced oxidative stress and cognitive impairment in a dose-dependent manner. HEAP also normalized the decrease in cholinesterase activity caused by seizures. Thus, HEAP showed protective effect against seizures, seizure-induced oxidative stress and cognitive impairment in rats.

Increased persistent Na+ current contributes to seizure in the slamdance bang-sensitive Drosophila mutant

There is clinical need to extend the understanding of epilepsy and to find novel approaches to treat this condition. Bang-sensitive (bs) Drosophila mutants, which exhibit reduced thresholds for seizure, offer an attractive possibility to combine tractable genetics, electrophysiology, and high-throughput screening. However, despite these advantages, the precise electrophysiological aberrations that contribute to seizure have not been identified in any bs mutant. Because of this, the applicability of Drosophila as a preclinical model has not yet been established. In this study, we show that electroshock of bs slamdance (sda) larvae was sufficient to induce extended seizure-like episodes. Whole cell voltage-clamp recordings from identified motoneurons (termed aCC and RP2) showed synaptic currents that were greatly increased in both amplitude and duration. Current-clamp recordings indicated that these inputs produced longer-lived plateau depolarizations and increased action potential firing in these cells. An analysis of voltage-gated currents in these motoneurons, in both first and third instar larvae, revealed a consistently increased persistent Na(+) current (I(Nap)) and a reduced Ca(2+) current in first instar larvae, which appeared normal in older third instar larvae. That increased I(Nap) may contribute to seizure-like activity is indicated by the observation that feeding sda larvae the antiepileptic drug phenytoin, which was sufficient to reduce I(Nap), rescued both seizure-like episode duration and synaptic excitation of motoneurons. In contrast, feeding of either anemone toxin, a drug that preferentially increases I(Nap), or phenytoin to wild-type larvae was sufficient to induce a bs behavioral phenotype. Finally, we show that feeding of phenytoin to gravid sda females was sufficient to both reduce I(Nap) and synaptic currents and rescue the bs phenotype in their larval progeny, indicating that a heightened predisposition to seizure may arise as a consequence of abnormal embryonic neural development.

Outlook: the postictal state--future directions for research

Future directions for research need to include studies of the various experimental and clinical aspects of the postictal state. More specifically, we need reliable and validated instruments that are able to measure the beginning and the end of the postictal period. Although a number of questionnaires are available, we currently have no evidence that these tests are able to assess drug effects on the postictal state, if they exist. In addition to the need for sensitive, reproducible and objective measures of the postictal state, we need instruments to differentiate the specific effects of AEDs or non-pharmacological therapy on the postictal state from indirect effects because of overall reduction in seizure severity. Although it would be naïve to think that the mechanisms of seizure termination are necessarily less complex than those involved in ictal onset, it is certainly worthwhile to explore strategies for the development of a new class of drugs for seizure control that work primarily through mechanisms involved in seizure termination and postictal refractoriness.

Comparative study of five antiepileptic drugs on a translational cognitive measure in the rat: relationship to antiepileptic property

RATIONALE

Antiepileptic drugs (AEDs) have been available for many years; yet, new members of this class continue to be identified and developed due to the limitations of existing drugs, which include a propensity for cognitive impairment. However, there is little preclinical information about the cognitive effects they produce, which clinically include deficits in attention and slowing of reaction time.

OBJECTIVES

The purpose of this study was to profile two first-generation AEDs, phenytoin and valproate, and three second-generation AEDs, levetiracetam, pregabalin and lacosamide. Initially, each drug was examined across a range of well characterised preclinical seizure tests, and then each drug was evaluated in the five-choice serial reaction time test (5-CSRTT) based on efficacious doses from the seizure tests.

MATERIALS AND METHODS

Each AED was tested for anti-seizure efficacy in either (1) the maximal electroshock seizure test, (2) s.c. PTZ seizure test, (3) amygdala-kindled seizures and (4) the genetic absence epilepsy rat of Strasbourg model of absence seizures. On completion of these studies, each drug was tested in rats trained to asymptotic performance in the 5-CSRTT (0.5 s SD, 5 s ITI, 100 trials). Male rats were used in all studies.

RESULTS

Each AED was active in at least one of the seizure tests, although only valproate was active in each test. In the 5-CSRT test, all drugs with the exception of levetiracetam, significantly slowed reaction time and increased omissions. Variable effects were seen on accuracy. The effect on omissions was reversed by increasing stimulus duration from 0.5 to 5 s, supporting a drug-induced attention deficit. Levetiracetam had no negative effect on performance; indeed, reaction time was slightly increased (i.e. faster).

CONCLUSIONS

These results highlight somewhat similar effects of phenytoin, valproate, pregabalin and lacosamide on attention and reaction time, and comparison to efficacious doses from the seizure tests support the view that there may be a better separation with the newer AEDs. Levetiracetam had no detrimental effect in the 5-CSRTT, which may be consistent with clinical experience where the drug is considered to be well tolerated amongst the AED class.

Differential effect of carbamazepine and oxcarbazepine on excitatory synaptic transmission in rat hippocampus

In this study, we have compared the effects of two structurally related compounds carbamazepine (CBZ) and oxcarbazepine (OXC), both in current use for the treatment of epilepsy and bipolar disorder, on fast excitatory transmission in rat hippocampal slices. Using electrophysiological recordings, we have investigated the effects of CBZ and OXC on repetitive action potential discharge of CA1 pyramidal neurons demonstrating that both compounds produced firing inhibition with similar IC(50) values. Moreover, we show that bath applied CBZ (0.01-1 mM) exerted a concentration-dependent decrease in the amplitude of the field excitatory postsynaptic potentials with an IC(50) of approximately 194.3 microM. When OXC was used at the same concentrations, the concentration-response curve was shifted to the right (IC(50) of approximately 711.07 microM). In addition, we demonstrated that CBZ and OXC reduced, to a different extent, both evoked excitatory postsynaptic currents and NMDA-, AMPA-, and KA-mediated inward currents, CBZ being more potent than OXC. These data highlight distinct presynaptic and postsynaptic sites of action for both compounds and suggest that CBZ, by markedly depressing postsynaptic ionotropic glutamate receptors-mediated responses, may produce more severe cognitive and memory impairment. Thus, we assume that relatively high doses of OXC could be better tolerated than therapeutically equivalent doses of CBZ, justifying the preferential use of OXC as first-line treatment in the therapy of neurological and psychiatric disorders, particularly when compared with CBZ.

Comparison of acute, chronic and post-treatment effects of carbamazepine and vinpocetine on hearing loss and seizures induced by 4-aminopyridine

OBJECTIVE

To compare the acute, chronic and post-treatment effects of the classic antiepileptic drug carbamazepine (CBZ) and the potential antiepileptic vinpocetine (VPC), successfully used in the treatment of brain vascular origin disorders, on 4-aminopyridine (4-AP)-induced increase in auditory threshold, brain-auditory-evoked-potentials (BAEPs) later waves alterations and epileptiform activity.

METHODS

BAEP and EEG recordings before and following 4-AP (3mg/kg, i.p.) were obtained in guinea pigs. One week after, the animals received a daily injection (i.p.) of vehicle, 3mg/kg VPC or 17 mg/kg CBZ for 13 days. The acute and chronic effects before and following 4-AP were tested at the 1st and last days, respectively, and the post-treatment effect 1 month after the end of treatment.

RESULTS

CBZ and 4-AP increased BAEPs threshold and BAEPs P4 wave latency. Chronic CBZ inhibited 4-AP-induced increase in P3 amplitude. In the VPC-treated group, all the 4-AP-induced BAEPs changes were prevented. Seizures were prevented in 50% and 75% of the animals by chronic CBZ and VPC, respectively. After acute VPC and after the end of VPC-treatment 4-AP failed to induce seizures in 50% of the animals.

CONCLUSION

VPC inhibits 4-AP-induced seizures and hearing loss, even after post-treatment, at a concentration about 10 times lower than CBZ.

SIGNIFICANCE

The complications in hearing that can accompany epilepsy can be prevented by VPC, indicating its advantage as an alternative antiepileptic.

Stabilizing dendritic structure as a novel therapeutic approach for epilepsy

People with epilepsy often experience long-term cognitive dysfunction and other neurological deficits, including memory loss, learning disabilities and neurobehavioral disorders, which may exhibit a progressive course correlating with worsening seizure control. Furthermore, a third of epilepsy patients have seizures that are intractable to all available treatments. Thus, novel therapies for seizures and the neurological comorbidities of epilepsy are desperately needed. As most current treatments are merely symptomatic therapies that suppress seizures, epilepsy researchers have recently realized the critical need for novel therapeutic strategies targeting the underlying mechanisms of epileptogenesis and seizure-related brain injury. Yet, to date, few such antiepileptogenic therapies have emerged or are even in developmental stages. Although many seizure medications modulate the functional or physiological activity of neurons, the methods for stabilizing the structure of neurons are relatively unexplored therapeutic strategies for epilepsy. Human pathological studies and animal models of epilepsy demonstrate obvious structural abnormalities in dendrites of neurons, which could contribute to neuronal dysfunction, epileptogenesis and cognitive/neurological deficits in epilepsy patients. This dendritic injury may be caused by activity-dependent breakdown of cytoskeletal elements, such as actin. Mechanistically targeted approaches to limit seizure-related structural changes in dendrites may represent a novel therapeutic strategy for treating epilepsy and its complications.

Drug assessment based on detection of L-glutamate released from C6 glioma cells using an enzyme-luminescence method

Monitoring of excitation activity of nerve cells is very useful for not only brain research but also assessment of the effects of various chemicals, including drugs and toxins. We previously reported a novel enzyme-luminescence method for real-time monitoring of l-glutamate release from C6 glioma cells with high levels of sensitivity ( approximately 10 nM) and temporal resolution (<1 s) using a luminescence plate reader. In the present study, we tested the applicability of this novel system for assessment of effects of drugs in vitro. Several drugs (e.g., veratridine and 4-aminopyridine) were administered to C6 glioma cells for inducing glutamate release. Moreover, antagonists of voltage-dependent Ca (2+) channels (e.g., nifedipine, flunarizine, and NiCl 2) and Na (+) channels (e.g., carbamazepine and lidocaine) were applied separately for evaluating the effects of these chemicals on glutamate release from the cells. The combined effect of carbamazepine and lidocaine was also investigated by using our method, and the combined effect was found to be more potent than that of single drug administration. These results indicated that the glutamate release from C6 cells was modulated by these drugs in a way similar to that found by using several conventional analytical techniques. We therefore conclude that the developed monitoring system for real-time detection of dynamic l-glutamate release from cells could be very useful for application to assessment of drugs acting on the nervous system.

Effects of carbamazepine, phenytoin, valproic acid, oxcarbazepine, lamotrigine, topiramate and vinpocetine on the presynaptic Ca2+ channel-mediated release of [3H]glutamate: Comparison with the Na+ channel-mediated release

The effect of carbamazepine, phenytoin, valproate, oxcarbazepine, lamotrigine and topiramate, that are among the most widely used antiepileptic drugs (AEDs), and of the new putative AED vinpocetine on the Ca(2+) channel-mediated release of [(3)H]Glu evoked by high K(+) in hippocampal isolated nerve endings was investigated. Results show that carbamazepine, oxcarbazepine and phenytoin reduced [(3)H]Glu release to high K(+) to about 30% and 55% at concentrations of 500 microM and 1500 microM, respectively; lamotrigine and topiramate to about 27% at 1500 microM; while valproate failed to modify it. Vinpocetine was the most potent and effective; 50 microM vinpocetine practically abolished the high K(+) evoked release of [(3)H]Glu. Comparison of the inhibition exerted by the AEDs on [(3)H]Glu release evoked by high K(+) with the inhibition exerted by the AEDs on [(3)H]Glu release evoked by the Na(+) channel opener, veratridine, shows that all the AEDs are in general more effective blockers of the presynaptic Na(+) than of the presynaptic Ca(2+) channel-mediated response. The high doses of AEDs required to control seizures are frequently accompanied by adverse secondary effects. Therefore, the higher potency and efficacy of vinpocetine to reduce the permeability of presynaptic ionic channels controlling the release of the most important excitatory neurotransmitter in the brain must be advantageous in the treatment of epilepsy.

Clinical development of antiepileptic drugs in adults

Over the last two decades, ten so-called newer antiepileptic drugs (AEDs) have been approved around the world, the majority of which have found and maintained a place in the seizure-fighting armamentarium for the whole spectrum of epilepsies and epileptic syndromes; some of these drugs have features that are improved compared with the older drugs. Within that same time period, the process of clinical development of AEDs has also undergone changes and has become much more complex and costly. Efforts are underway to shift decision-making about the clinical viability of AED candidates to earlier development stages, using the concept of translational medicine. However, thus far all of the newer AEDs have undergone a standard development as an adjunct in the control of adult partial seizures; in some cases, development has been expanded to other seizure types and pediatric syndromes. Currently, the path to global approval for use in monotherapy is under review and is often debated with regulatory authorities. Clinical treatment guidelines consider randomized, blinded, well controlled studies as the premier level of evidence-based medicine; these studies originate mostly in confirmatory phases of the development program. However, with the rigid designs and criteria in regulatory driven trials, effectiveness in the clinical practice setting may not be sufficiently predicted by these studies, leading to frustrations from individual practitioners. Finally, additional safety issues regularly occur only after the postlaunch exposure to a broader population making necessary a continuing, and thorough, pharmacovigilance after the AED has come to market.

Effects of carbamazepine, phenytoin, lamotrigine, oxcarbazepine, topiramate and vinpocetine on Na+ channel-mediated release of [3H]glutamate in hippocampal nerve endings

Several of the most effective antiepileptic drugs are believed to stop the paroxysmal neuronal activity acting as Na(+) channel blockers. However, no single study comparing in parallel the potency and efficacy of the most commonly used antiepileptic drugs on brain Na(+) channel-mediated responses is available. In the present study the effects of increasing concentrations of carbamazepine, phenytoin, lamotrigine, oxcarbazepine and topiramate, which are among the most frequently used antiepileptic drugs, and of the new putative antiepileptic drug, vinpocetine, on the release of glutamate (Glu) elicited by the Na(+) channel opener, veratridine were investigated in hippocampal isolated nerve endings preloaded with the labeled excitatory amino acid neurotransmitter. The present results show that carbamazepine, phenytoin, lamotrigine and oxcarbazepine, in the range from 150 to 1500 microM, progressively inhibit [(3)H]Glu release induced by veratridine. Also vinpocetine progressively inhibits the veratridine-induced response, but in a much lower range of concentrations (from 1.5 to 15 microM), whereas topiramate only exerts a modest inhibition (20%) of Glu release to veratridine at the highest dose tested (1500 microM). These results indicate that the mechanism of action of several of the most widely used antiepileptic drugs involves reduction in cerebral presynaptic voltage sensitive Na(+) channels permeability. Considering that the high doses of antiepileptic drugs required to control seizures are frequently accompanied by adverse secondary effects, the higher potency of vinpocetine to reduce Na(+) channels permeability might be advantageous.

Additive effects of antiepileptic drugs and pentylenetetrazole on hearing

The long-term effect of three of the most widely used antiepileptic drugs at relevant doses on the hearing decline that accompanies pentylenetetrazole (PTZ)-induced experimental epilepsy was investigated here, and compared with the effect of vinpocetine (VPC), which is a drug with antiepileptic potential. For this purpose, cortical activity (monitored by the EEG) and auditory sensitivity, as indicated by brainstem auditory evoked potential (BAEP) threshold at 4 and 8 kHz tone frequencies, were determined in guinea pigs daily injected for 28 days with vehicle (control), 20 mg/kg carbamazepine (CBZ), 6 mg/kg phenytoin (PHT), 30 mg/kg valproate (VPA) or 2 mg/kg vinpocetine (VPC) before and after the administration of PTZ at a convulsing dose (100 mg/kg). Results show that all the antiepileptic drugs tested were more or less effective in preventing PTZ-induced seizures. The long-term treatment with VPC decreased the auditory threshold, whereas the long-term treatment with CBZ, PHT or VPA increased the auditory threshold to a similar extent as the convulsing agent, PTZ. The combined effects of the antiepileptic drugs and PTZ on auditory threshold were additive. Therefore, only VPC prevented the increase in the auditory threshold induced by PTZ. It is concluded that the hearing loss produced by the long-term treatment with the most commonly used antiepileptic drugs could be aggravated by the illness. The prevention exerted by VPC on the hearing decline that accompanies experimental epilepsy, along with its capacity to control seizures at low doses in this and other animal models of epilepsy, would make VPC a valid candidate for the treatment of epilepsy.

Single and combined effects of carbamazepine and vinpocetine on depolarization-induced changes in Na+, Ca2+ and glutamate release in hippocampal isolated nerve endings

The single and combined effects of carbamazepine and vinpocetine on the release of the excitatory amino acid neurotransmitter glutamate, on the rise in internal Na+ (Na(i), as determined with SBFI), and on the rise in internal Ca2+ (Ca(i), as determined with fura-2) induced by an increased permeability of presynaptic Na+ channels, with veratridine, or by an increased permeability of presynaptic Ca2+ channels with high K+, were investigated in isolated hippocampal nerve endings. The present study shows that carbamazepine and vinpocetine, both inhibit dose dependently the release of preloaded [3H]Glu induced by veratridine. However, carbamazepine is two orders of magnitude less potent than vinpocetine. The calculated IC(50)'s for carbamazepine and vinpocetine to inhibit veratridine-induced [3H]Glu release are 200 and 2 microM, respectively. Consistently 150 microM carbamazepine and 1.5 microM vinpocetine reduce the veratridine-induced rise in Na(i) in a similar extent. The single effects of carbamazepine and of vinpocetine on the presynaptic Na+ channel mediated responses, namely the rise in Na(i) and the release of Glu induced by veratridine, are additive. Responses that depend on the entrance of external Ca2+ via presynaptic Ca2+ channels, such as the release of [3H]Glu and the rise in Ca(i) induced by high K+, are insensitive to 300 microM carbamazepine and slightly reduced by 5 microM vinpocetine. It is concluded that the additive effects of carbamazepine, which is one of the most common antiepileptic drugs, and vinpocetine that besides its known neuroprotective action and antiepileptic potential is a memory enhancer, may perhaps be advantageous in the treatment of epileptic patients.

Epileptogenesis and rational therapeutic strategies

The understanding of neurobiological mechanisms of epileptogenesis is essential for rational approaches for a possible disease modification as well as treatment of underlying causes of the epilepsies. More effort is necessary to translate results from basic investigations into new approaches for clinical research and to better understand a relationship with findings from clinical studies. The following report is a condensed synapsis in which molecular mechanisms of epileptogenesis, pharmacological modulation of epileptogenesis, evidence based therapy, refractoriness and prediction of outcome is provided in order to stimulate further collaborative international research.

Natural history of treated childhood-onset epilepsy: prospective, long-term population-based study

It is not well known how often drug resistance, a major clinical problem, occurs early or late in the course of epilepsy and how often epilepsy follows a continuous, remitting or relapsing-remitting pattern. To provide evidence if, in fact, different patterns of evolution of drug resistance and remission exist, a prospective, long-term population-based study of 144 patients followed on the average for 37.0 years (SD 7.1, median 40.0, range 11-42) since their first seizure before the age of 16 years was performed. At the end of follow-up, 67% of 144 patients were in terminal remission, on or off antiepileptic drugs. Early remission, starting within the first year of treatment, was seen in 45 patients (31%). In 23 (16%) of them, first remission continued, uninterrupted by relapse, to terminal remission. Late remission with a mean delay of 9 years was achieved by a further 72 patients (50%), including 46 (32%) patients who achieved terminal remission without any relapse and suggested, together with 23 patients, a remitting course. Following a relapse after early or late remission, 28 (19%) patients achieved terminal remission, suggesting a remitting-relapsing pattern. Altogether 20 patients (14%) did not re-enter remission, indicating a worsening course of epilepsy. Twenty-seven (19%) patients were drug-resistant from the start to the end of follow-up. In conclusion, half the patients with childhood-onset epilepsy will eventually enter terminal remission without relapse and a fifth after relapse. One-third will have a poor long-term outcome in terms of persistent seizures after remission or without any remission ever.

Drug Resistance in Epilepsy: Putative Neurobiologic and Clinical Mechanisms

Drug-resistant epilepsy with uncontrolled severe seizures despite state-of-the-art medical treatment continues to be a major clinical problem for up to one in three patients with epilepsy. Although drug resistance may emerge or remit in the course of epilepsy or its treatment, in most patients, drug resistance seems to be continuous and to occur de novo. Unfortunately, current antiepileptic drugs (AEDs) do not seem to prevent or to reverse drug resistance in most patients, but add-on therapy with novel AEDs is able to exert a modest seizure reduction in as many as 50% of patients in short-term clinical trials, and a few become seizure free during the trial. It is not known why and how epilepsy becomes drug resistant, while other patients with seemingly identical seizure types can achieve seizure control with medication. Several putative mechanisms underlying drug resistance in epilepsy have been identified in recent years. Based on experimental and clinical studies, two major neurobiologic theories have been put forward: (a) removal of AEDs from the epileptogenic tissue through excessive expression of multidrug transporters, and (b) reduced drug-target sensitivity in epileptogenic brain tissue. On the clinical side, genetic and clinical features and structural brain lesions have been associated with drug resistance in epilepsy. In this article, we review the laboratory and clinical evidence to date supporting the drug-transport and the drug-target hypotheses and provide directions for future research, to define more clearly the role of these hypotheses in the clinical spectrum of drug-resistant epilepsy.

Seizure suppression by gain-of-function escargot mutations

Suppressor mutations provide potentially powerful tools for examining mechanisms underlying neurological disorders and identifying novel targets for pharmacological intervention. Here we describe mutations that suppress seizures in a Drosophila model of human epilepsy. A screen utilizing the Drosophila easily shocked (eas) "epilepsy" mutant identified dominant suppressors of seizure sensitivity. Among several mutations identified, neuronal escargot (esg) reduced eas seizures almost 90%. The esg gene encodes a member of the snail family of transcription factors. Whereas esg is normally expressed in a limited number of neurons during a defined period of nervous system development, here normal esg was expressed in all neurons and throughout development. This greatly ameliorated both the electrophysiological and the behavioral epilepsy phenotypes of eas. Neuronal esg appears to act as a general seizure suppressor in the Drosophila epilepsy model as it reduces the susceptibility of several seizure-prone mutants. We observed that esg must be ectopically expressed during nervous system development to reduce seizure susceptibility in adults. Furthermore, induction of esg in a small subset of neurons (interneurons) will reduce seizure susceptibility. A combination of microarray and computational analyses revealed 100 genes that represent possible targets of neuronal esg. We anticipate that some of these genes may ultimately serve as targets for novel antiepileptic drugs.