Development Of New Antiepileptic Drugs Research Articles

Neuroprotective effects of chlorogenic acid against oxidative stress in rats subjected to lithium-pilocarpine-induced status epilepticus.

Epilepsy is a condition marked by sudden, self-sustained, and recurring brain events, showcasing unique electro-clinical and neuropathological phenomena that can alter the structure and functioning of the brain, resulting in diverse manifestations. Antiepileptic drugs (AEDs) can be very effective in 30% of patients in controlling seizures. Several factors contribute to this: drug resistance, individual variability, side effects, complexity of epilepsy, incomplete understanding, comorbidities, drug interactions, and no adherence to treatment. Therefore, research into new AEDs is important for several reasons such as improved efficacy, reduced side effects, expanded treatment options, treatment for drug-resistant epilepsy, improved safety profiles, targeted therapies, and innovation and progress. Animal models serve as crucial biological tools for comprehending neuronal damage and aiding in the discovery of more effective new AEDs. The utilization of antioxidant agents that act on the central nervous system may serve as a supplementary approach in the secondary prevention of epilepsy, both in laboratory animals and potentially in humans. Chlorogenic acid (CGA) is a significant compound, widely prevalent in numerous medicinal and food plants, exhibiting an extensive spectrum of biological activities such as neuroprotection, antioxidant, anti-inflammatory, and analgesic effects, among others. In this research, we assessed the neuroprotective effects of commercially available CGA in Wistar rats submitted to lithium-pilocarpine-induced status epilepticus (SE) model. After 72-h induction of SE, rats received thiopental and were treated for three consecutive days (1st, 2nd, and 3rd doses). Next, brains were collected and studied histologically for viable cells in the hippocampus with staining for cresyl-violet (Nissl staining) and for degenerating cells with Fluoro-Jade C (FJC) staining. Moreover, to evaluate oxidative stress, the presence of malondialdehyde (MDA) and superoxide dismutase (SOD) was quantified. Rats administered with CGA (30 mg/kg) demonstrated a significant decrease of 59% in the number of hippocampal cell loss in the CA3, and of 48% in the hilus layers after SE. A significant reduction of 75% in the cell loss in the CA3, shown by FJC+ staining, was also observed with the administration of CGA (30 mg/kg). Furthermore, significant decreases of 49% in MDA production and 72% in the activity of SOD were seen, when compared to animals subjected to SE that received vehicle. This study introduces a novel finding: the administration of CGA at a dosage of 30 mg/kg effectively reduced oxidative stress induced by lithium-pilocarpine, with its effects lasting until the peak of neural damage 72 h following the onset of SE. Overall, the research and development of new AEDs are essential for advancing epilepsy treatment, improving patient outcomes, and ultimately enhancing the quality of life for individuals living with epilepsy.

Efficacy and tolerability of rufinamide in the treatment of Lennox–Gastaut syndrome (experience of the Svt. Luka’s Association of Medical Institutions)

Background. Lennox–Gastaut syndrome (LGS) is a classic developmental and epileptic encephalopathy with a debut in childhood, characterized by resistance to therapy, a severe course, and an unfavorable prognosis. Due to the existing difficulties in treatment of LGS, hopes are pinned on development of new antiepileptic drugs with fundamentally different mechanisms of action, aimed specifically at the treatment of this severe form of epilepsy.Rufinamide (Inovelon®) is a new antiepileptic drug registered in the Russian Federation for use in the adjunctive therapy of LGS in patients older than 1 year. The main mechanism of action of rufinamide is the restriction of neuronal discharges associated with the blocking effect on sodium channels (regulation of sodium channels activity by increasing duration of their inactive state), and stabilization of neuronal membranes. The drug has a number of advantages concernung pharmacokinetic parameters and efficacy (including a wide spectrum of antiepileptic activity, good oral absorption, absence of active metabolites, urinary excretion, low affinity for plasma proteins, biotransformation without cytochrome P450 isoenzymes, low risk of drug interactions) and fairly good tolerability. The daily dose of rufinamide varies from 600 mg (with simultaneous administration of valproate) to 1000 mg (if the patient does not take valproate) in children over 4 years of age with a body weight of less than 30 kg and up to 2200–3200 mg in children over 4 years of age with a body weight of more than 30 kg and in adults; in children under 4 years of age, the maximum daily dose in combination with valproate is 30 mg/kg, and without valproic acid – 45 mg/kg.Aim. To analyze the efficacy and tolerability of rufinamide in the treatment of epilepsy based on the long-term experience of using the drug in the Svt. Luka’s Association of Medical Institutions.Materials and methods. We observed 64 patients aged from 1.5 to 26 years (44 men, 20 women) treated with rufinamide (Inovelon®). Among them, the structural etiology LGS was diagnosed in 36 patients, the genetic and presumably genetic etiology LGS – in 28. In all cases, rufinamide was used in accordance with approved indications as an additional antiepileptic drug, more often in combination with valproate, topiramate, levetiracetam or lamotrigine. Titration of the drug was carried out according to the recommendations in the instructions for use, up to a therapeutic dose that ranged from 200 to 1600 mg/day (in most cases from 400 to 1200 mg/day), depending on age and concomitant therapy.Results and conclusion. Remission of all types of seizures was registered in 17 (26.6 %) patients, and a decrease in the incidence of seizures by more than 50 % was recorded in 28 (43.8 %) patients. Of them, 13 patients demonstrated reduction in seizures frequency by more than 75–90 % and remission of one of several types of seizures. In general, the therapeutic effect (reduction of seizures frequency by at least 50 %) was achieved in 45 (70.3 %) of 64 patients. A decrease in seizures frequency of by at least 50 % was observed in 8 (12.5 %) patients; in 10 (15.6 %) patients, rufinamide therapy was not effective; in 1 (1.56 %) case an aggravation of bilateral convulsive seizures was noted when rufinamide was administered.In most cases, rufinamide is well tolerated. Our patients had side effects in 10 (15.6 %) cases. Only in 2 (3.1 %) cases, rufinamide was withdrawn directly due to side effects (the reason for withdrawal in these cases was an allergic reaction and psychosis).The retention rate for therapy lasting 1 year or more is 65.6 % (42 of 64 patients).Thus, our data have demonstrated efficacy and good tolerability of rufinamide in treating epileptic seizures associated with LGS, confirming numerous literature data. However, in our analysis, a higher rate of seizure remission was obtained, although we have included patients with mainly resistant forms of epilepsy in the analysis.

Recent Progress in the Development of New Antiepileptic Drugs with Novel Targets.

Epilepsy is a chronic neurological disorder that affects approximately 50-70 million people worldwide. Epilepsy has a significant economic and social burden on patients as well as on the country. The recurrent, spontaneous seizure activity caused by abnormal neuronal firing in the brain is a hallmark of epilepsy. The current antiepileptic drugs provide symptomatic relief by restoring the balance of excitatory and inhibitory neurotransmitters. Besides, about 30% of epileptic patients do not achieve seizure control. The prevalence of adverse drug reactions, including aggression, agitation, irritability, and associated comorbidities, is also prevalent. Therefore, researchers should focus on developing more effective, safe, and disease-modifying agents based on new molecular targets and signaling cascades. This review overviews several clinical trials that help identify promising new targets like lactate dehydrogenase inhibitors, c-jun n-terminal kinases, high mobility group box-1 antibodies, astrocyte reactivity inhibitors, cholesterol 24-hydroxylase inhibitors, glycogen synthase kinase-3 beta inhibitors, and glycolytic inhibitors to develop a new antiepileptic drug. Approximately 30% of epileptic patients do not achieve seizure control. The current anti-seizure drugs are not disease modifying, cure or prevent epilepsy. Lactate dehydrogenase inhibitor, cholesterol 24-hydroxylase inhibitor, glycogen synthase kinase-3 beta inhibitors, and mTOR inhibitors have a promising antiepileptogenic effect.

Development of Antiepileptic Drugs throughout History: From Serendipity to Artificial Intelligence.

This article provides a comprehensive narrative review of the history of antiepileptic drugs (AEDs) and their development over time. Firstly, it explores the significant role of serendipity in the discovery of essential AEDs that continue to be used today, such as phenobarbital and valproic acid. Subsequently, it delves into the historical progression of crucial preclinical models employed in the development of novel AEDs, including the maximal electroshock stimulation test, pentylenetetrazol-induced test, kindling models, and other animal models. Moving forward, a concise overview of the clinical advancement of major AEDs is provided, highlighting the initial milestones and the subsequent refinement of this process in recent decades, in line with the emergence of evidence-based medicine and the implementation of increasingly rigorous controlled clinical trials. Lastly, the article explores the contributions of artificial intelligence, while also offering recommendations and discussing future perspectives for the development of new AEDs.

The opposite effect of convulsant drugs on neuronal and endothelial nitric oxide synthase - A possible explanation for the dual proconvulsive/anticonvulsive action of nitric oxide.

Nitric oxide (NO) participates in processes such as endothelium-dependent vasodilation and neurotransmission/neuromodulation. The role of NO in epilepsy is controversial, attributing it to anticonvulsant but also proconvulsant properties. Clarification of this dual effect of NO might lead to the development of new antiepileptic drugs. Previous results in our laboratory indicated that this contradictory role of NO in seizures could depend on the nitric oxide synthase (NOS) isoform involved, which could play opposite roles in epileptogenesis, one of them being proconvulsant but the other anticonvulsant. The effect of convulsant drugs on neuronal NO (nNO) and endothelial NO (eNO) levels was investigated. Considering the distribution of neuronal and endothelial NOS in neurons and astrocytes, resp., primary cultures of neurons and astrocytes were used as a study model. The effects of convulsant drugs pentylenetetrazole, thiosemicarbazide, 4-aminopyridine and bicuculline on NO levels were studied, using a spectrophotometric method. Their effects on NO levels in neurons and astrocytes depend on the concentration and time of treatment. These convulsant drugs caused an increase in nNO, but a decrease in eNO was proportional to the duration of treatment in both cases. Apparently, nNO possesses convulsant properties mediated by its effect on the glutamatergic and GABAergic systems, probably through GABAA receptors. Anticonvulsant properties of eNO may be the consequence of its effect on endothelial vasodilation and its capability to induce angiogenesis. Described effects last as seizures do. Considering the limitations of these kinds of studies and the unexplored influence of inducible NO, further investigations are required.

Valproic Acid-Induced Upregulation of Multidrug Efflux Transporter ABCG2/BCRP via PPARα-Dependent Mechanism in Human Brain Endothelial Cells.

Despite the progress made in the development of new antiepileptic drugs (AEDs), poor response to them is a rising concern in epilepsy treatment. Of several hypotheses explaining AED treatment failure, the most promising theory is the overexpression of multidrug transporters belonging to ATP-binding cassette (ABC) transporter family at blood-brain barrier. Previous data show that AEDs themselves can induce these transporters, in turn affecting their own brain bioavailability. Presently, this induction and the underlying regulatory mechanism involved at human blood-brain barrier is not well elucidated. Herein, we sought to explore the effect of most prescribed first- and second-line AEDs on multidrug transporters in human cerebral microvascular endothelial cells, hCMEC/D3. Our work demonstrated that exposure of these cells to valproic acid (VPA) induced mRNA, protein, and functional activity of breast cancer resistance protein (BCRP/ABCG2). On examining the substrate interaction status of AEDs with BCRP, VPA, phenytoin, and lamotrigine were found to be potential BCRP substrates. Furthermore, we observed that siRNA-mediated knockdown of peroxisome proliferator-activated receptor alpha (PPARα) or use of PPARα antagonist, resulted in attenuation of VPA-induced BCRP expression and transporter activity. VPA was found to increase PPARα expression and trigger its translocation from cytoplasm to nucleus. Findings from chromatin immunoprecipitation and luciferase assays showed that VPA enhances the binding of PPARα to its response element in the ABCG2 promoter, resulting in elevated ABCG2 transcriptional activity. Taken together, these in vitro findings highlight PPARα as the potential molecular target to prevent VPA-mediated BCRP induction, which may have important implications in VPA pharmacoresistance. SIGNIFICANCE STATEMENT: Induction of multidrug transporters at blood-brain barrier can largely affect the bioavailability of the substrate antiepileptic drugs in the brains of patients with epilepsy, thus affecting their therapeutic efficacy. The present study reports a mechanistic pathway of breast cancer resistance protein (BCRP/ABCG2) upregulation by valproic acid in human brain endothelial cells via peroxisome proliferator-activated receptor alpha involvement, thereby providing a potential strategy to prevent valproic acid pharmacoresistance in epilepsy.

Design, Synthesis, and Evaluation of Anticonvulsant Activities of New Triazolopyrimidine Derivatives.

Epilepsy, a severe brain disease affecting a large population, is treated mainly by antiepileptic drugs (AEDs). However, toxicity, intolerance, and low efficiency of the available AEDs have prompted the continual attempts in the discovery of new AEDs. In this study, we discovered a skeleton of triazolopyrimidine for the development of new AEDs. The design, synthesis, in vivo anticonvulsant activity evaluation of triazolopyrimidines (3a–3i and 6a–6e), and pyrazolopyrimidines (4a–4i) are reported. We found that most triazolopyrimidines showed anticonvulsive activity in the maximal electroshock (MES) and pentetrazol (PTZ)-induced seizure models. On the contrary, pyrazolopyrimidines (4a–4i) showed weak or no protective effects. Among the tested derivatives, compound 6d, holding a median effective dose (ED50) of 15.8 and 14.1 mg/kg against MES and PTZ-induced seizures, respectively, was found to be the most potent one. Moreover, the protection index (PI) value of 6d was significantly higher than that of the available AEDs such as valproate, carbamazepine, and diazepam. The antiepileptic efficacy of compound 6d was also observed in the 3-mercaptopropionic acid and bicuculline-induced seizure models. Antagonistic effects of flumazenil and 3-MP for the anticonvulsive activity of 6d and also the radioligand-binding assay confirmed the involvement of GABA receptors, at least benzodiazepine (BZD) receptor, in the anticonvulsant activity of compound 6d. The docking study of compounds 4e and 6d with GABAA receptor confirmed and explained their affinity to the BZD receptors.

Role of Magnesium Supplementation in Children with West Syndrome: A Randomized Controlled Clinical Trial.

Objectives West syndrome is a severe epileptic encephalopathy of young age. It is characterized by a clinico-electrical triad of infantile epileptic spasms, regression or arrest of psychomotor development, and hypsarrhythmia. In the last two decades, the large progress in the development of newer antiepileptic drugs has allowed us to have a vast choice of treatment options to control spasms, although they often fail to do so. Thus, there is a need to explore other treatment options.Materials & Methods Subjects in this open-labelled randomized control trial were included newly diagnosed children of age between 3 months and 5 years of both genders. A total of 52 children were recruited and randomized into two groups: an intervention group (n=30) and a non-intervention group (n=22). Magnesium sulphate was provided for the intervention group but not for the non-intervention one. Both groups received the rest of the treatments, including adrenocorticotropic hormone and antiepileptic drugs. The follow-up period was three months, at the end of which a per-protocol analysis was performed.Results There was no significant difference in seizure control and neurodevelopmental outcome between both groups, but electroencephalogram significantly improved in the intervention group compared to the control. Also, the clinical response was better in patients with normal initial serum magnesium levels in the intervention group (p=0.003) than in other patients.Conclusion Magnesium supplementation may be helpful in children with West syndrome.

West syndrome - epileptic encephalopathy at early infancy

West syndrome (WS), synonymously infantile spasm or epileptic spasm, is a rare type of epileptic encephalopathy occurring at early infancy that exists with variable life expectancy. It is the most common form of epileptic encephalopathy. WS presents with spasms marked by extensor or mixed movements with distinct electroencephalogram (EEG) pattern of hypsarrhythmia, flexor and psychomotor arrest. Children with west syndrome always depict abnormal EEG, but sometimes the abnormality is seen only during sleep. The incidence of infantile spasms is found closer to 1 in 2,000 children, that typically begins between 2-12 months of age and peaks between 4-8 months of age. It is observed in otherwise healthy infants and also among infants with abnormal cognitive development. If this spasm happens in older subjects, they are preferably called "epileptic spasms" rather than infantile spasms. The goal for treatment of infantile spasms is to have complete control of spasms. Hormonal therapy with ACTH or vigabatrin is the mainstay of treatment. In spite of the development of new antiepileptic drugs (AEDs), about 35-40% of cases are drug-resistant. Children affected with the west syndrome can be cured, but a successful therapy often depends on the timely diagnosis. This case report is one evidence highlighting the treatment strategy for the west syndrome, and this could be useful for any further study regarding this topic.

Upregulation of lactate dehydrogenase A in a chronic model of temporal lobe epilepsy

The ketogenic diet treatment is effective for drug-resistant epilepsy. Because its antiepileptic effect is associated with lactate dehydrogenase (LDH), drug development is possible by targeting LDH enzymes. Seizures in rodent models are suppressed by inhibiting LDH; however, it remains unclear whether LDH in the brain is changed by seizures. In the present study, we examined the expression of LDH subunits (LDHA and LDHB) in a chronic model of temporal lobe epilepsy, in which seizures were induced by the microinjection of kainate into the mouse hippocampus. Using Western blot analyses, we found that LDHA expression was increased in the hippocampus of the chronic seizure model, whereas LDHB expression was not. Lactate levels in the hippocampus were also increased in this seizure model, suggesting elevated LDH enzymatic activities. Furthermore, the inhibition of LDHA suppressed spontaneous paroxysmal discharges in vivo in the chronic seizure model. In conclusion, our results show that chronic seizures increase LDHA, and conversely, the inhibition of LDHA suppresses seizures, which supports LDHA as a molecular target for the development of new antiepileptic drugs.

Cannabidiol (CBD) Inhibited Rhodamine-123 Efflux in Cultured Vascular Endothelial Cells and Astrocytes Under Hypoxic Conditions.

Despite the constant development of new antiepileptic drugs (AEDs), more than 30% of patients develop refractory epilepsy (RE) characterized by a multidrug-resistant (MDR) phenotype. The “transporters hypothesis” indicates that the mechanism of this MDR phenotype is the overexpression of ABC transporters such as P-glycoprotein (P-gp) in the neurovascular unit cells, limiting access of the AEDs to the brain. Recent clinical trials and basic studies have shown encouraging results for the use of cannabinoids in RE, although its mechanisms of action are still not fully understood. Here, we have employed astrocytes and vascular endothelial cell cultures subjected to hypoxia, to test the effect of cannabidiol (CBD) on the P-gp-dependent Rhodamine-123 (Rho-123) efflux. Results show that during hypoxia, intracellular Rho-123 accumulation after CBD treatment is similar to that induced by the P-gp inhibitor Tariquidar (Tq). Noteworthy, this inhibition is like that registered in non-hypoxia conditions. Additionally, docking studies predicted that CBD could behave as a P-gp substrate by the interaction with several residues in the α-helix of the P-gp transmembrane domain. Overall, these findings suggest a direct effect of CBD on the Rho-123 P-gp-dependent efflux activity, which might explain why the CBD add-on treatment regimen in RE patients results in a significant reduction in seizure frequency.

GABAA receptor β3 subunit mutation D120N causes Lennox–Gastaut syndrome in knock-in mice

The Lennox–Gastaut syndrome is a devastating early-onset epileptic encephalopathy, associated with severe behavioural abnormalities. Its pathophysiology, however, is largely unknown. A de novo mutation (c.G358A, p.D120N) in the human GABA type-A receptor β3 subunit gene (GABRB3) has been identified in a patient with Lennox–Gastaut syndrome. To determine whether the mutation causes Lennox–Gastaut syndrome in vivo in mice and to elucidate its mechanistic effects, we generated the heterozygous Gabrb3+/D120N knock-in mouse and found that it had frequent spontaneous atypical absence seizures, as well as less frequent tonic, myoclonic, atonic and generalized tonic–clonic seizures. Each of these seizure types had a unique and characteristic ictal EEG. In addition, knock-in mice displayed abnormal behaviours seen in patients with Lennox–Gastaut syndrome including impaired learning and memory, hyperactivity, impaired social interactions and increased anxiety. This Gabrb3 mutation did not alter GABA type-A receptor trafficking or expression in knock-in mice. However, cortical neurons in thalamocortical slices from knock-in mice had reduced miniature inhibitory post-synaptic current amplitude and prolonged spontaneous thalamocortical oscillations. Thus, the Gabrb3+/D120N knock-in mouse recapitulated human Lennox–Gastaut syndrome seizure types and behavioural abnormalities and was caused by impaired inhibitory GABAergic signalling in the thalamocortical loop. In addition, treatment with antiepileptic drugs and cannabinoids ameliorated atypical absence seizures in knock-in mice. This congenic knock-in mouse demonstrates that a single-point mutation in a single gene can cause development of multiple types of seizures and multiple behavioural abnormalities. The knock-in mouse will be useful for further investigation of the mechanisms of Lennox–Gastaut syndrome development and for the development of new antiepileptic drugs and treatments.

Catalpol and Mannitol, Two Components of Rehmannia glutinosa, Exhibit Anticonvulsant Effects Probably via GABAA Receptor Regulation.

Epilepsy is a brain disorder that affects millions of people worldwide and is usually managed using currently available antiepileptic drugs, which result in adverse effects and are ineffective in approximately 20–25% of patients. Thus, there is growing interest in the development of new antiepileptic drugs with fewer side effects. In a previous study, we showed that a Rehmannia glutinosa (RG) water extract has protective effects against electroshock- and pentylenetetrazol (PTZ)-induced seizures, with fewer side effects. In this study, the objective was to identify the RG components that are responsible for its anticonvulsant effects. Initially, a number of RG components (aucubin, acteoside, catalpol, and mannitol) were screened, and the anticonvulsant effects of different doses of catalpol, mannitol, and their combination on electroshock- and chemically (PTZ or strychnine)-induced seizures in mice, were further assessed. Gamma-aminobutyric acid (GABA) receptor binding assay and electroencephalography (EEG) analysis were conducted to identify the potential underlying drug mechanism. Additionally, treated mice were tested using open-field and rotarod tests. Catalpol, mannitol, and their combination increased threshold against electroshock-induced seizures, and decreased the percentage of seizure responses induced by PTZ, a GABA antagonist. GABA receptor binding assay results revealed that catalpol and mannitol are associated with GABA receptor activity, and EEG analysis provided evidence that catalpol and mannitol have anticonvulsant effects against PTZ-induced seizures. In summary, our results indicate that catalpol and mannitol have anticonvulsant properties, and may mediate the protective effects of RG against seizures.

Preclinical evaluation of 1,2,4-triazole-based compounds targeting voltage-gated sodium channels (VGSCs) as promising anticonvulsant drug candidates.

Epilepsy is a chronic neurological disorder affecting nearly 65-70 million people worldwide. Despite the observed advances in the development of new antiepileptic drugs (AEDs), still about 30-40% of patients cannot achieve a satisfactory seizure control. In our current research, we aimed at using the combined results of radioligand binding experiments, PAMPA-BBB assay and animal experimentations in order to design a group of compounds that exhibit broad spectrum of anticonvulsant activity. The synthesized 4-alkyl-5-substituted-1,2,4-triazole-3-thione derivatives were primarily screened in the maximal electroshock-induced seizure (MES) test in mice. Next, the most promising compounds (17, 22) were investigated in 6 Hz (32 mA) psychomotor seizure model. Protective effect of compound 22 was almost similar to that of levetiracetam. Moreover, these compounds did not induce genotoxic and hemolytic changes in human cells as well as they were characterized by low cellular toxicity. Taking into account the structural requirements for good anticonvulsant activity of 4-alkyl-5-aryl-1,2,4-triazole-3-thiones, it is visible that small electron-withdrawing substituents attached to phenyl ring have beneficial effects both on affinity towards VGSCs and protective activity in the animal models of epilepsy.

Chirality as an Important Factor for the Development of New Antiepileptic Drugs.

In recent years, chiral molecules (especially enantiomers) have occupied a significant place in pharmaceutical industry and have played a prominent role in the development of new drugs. Individual stereoisomers exhibit marked differences in pharmacodynamic, pharmacokinetic, and toxicological properties. Therefore, there is currently considerable interest in fully characterizing and examining both enantiomers in the early stages of new drug development. Despite the fact that epilepsy is a complex disease and that a given drug's mechanism of action may be multidirectional and not always fully understood, significant differences have been observed in the anticonvulsant activity of individual stereoisomers. Therefore, between 1996 and 2018, among 14 new antiepileptic drugs (AEDs) approved for the treatment of epilepsy, as many as seven are chiral and introduced to the market in the single-enantiomer (or diastereomer) form. This review provides an overview of the impact of chirality on the development and discovery of new AEDs that have entered into clinical trials or preclinical studies. These new AEDs were developed by applying the single-enantiomer approval strategy. Herein we focus our attention on the main synthetic pathways of stereoisomers, as well as on the influence of chirality on pharmacodynamic, pharmacokinetic, and/or toxicological properties.

Design, Synthesis, Anticonvulsant Activity, Preclinical Study and Pharmacokinetic Performance of N-{[3-(4-chlorophenyl)-4-oxo-3, 4-dihydroquinazolin- 2-yl] methyl}, 2-[(2-isopropyl-5-methyl) 1-cyclo Hexylidene] Hydrazinecarboxamide.

N-{[3-(4-chlorophenyl)-4-oxo-3, 4-dihydroquinazolin-2-yl] methyl}, 2-[(2- isopropyl-5-methyl) 1-cyclohexylidene] hydrazinecarboxamide QS11 was designed by computational study. It possessed essential pharmacophoric features for anticonvulsant activity and showed good docking with iGluRs (Kainate) glutamate receptor. QSAR and ADMET screening results suggested that QS11 would possess good potency for anticonvulsant activity. QS11 was synthesised and evaluated for its anticonvulsant activity and neurotoxicity. QS11 showed protection in strychnine, thiosemicarbazide, 4-aminopyridine and scPTZ induced seizure models and MES seizure model. QS11 showed higher ED50, TD50 and PI values as compared to the standard drugs in both MES and scPTZ screen. A high safety profile (HD50/ED50 values) was noted and hypnosis, analgesia, and anaesthesia were only observed at higher doses. No considerable increase or decrease in the concentration of liver enzymes was observed. Optimized QS11 was subjected to preclinical (in-vivo) studies and the pharmacokinetic performance of the sample was investigated. The result revealed that the pharmacokinetic performance of QS11 achieved maximum plasma concentrations (Cmax) of 0.315 ± 0.011 µg/mL at Tmax of 2.0 ± 0.13 h, area under the curve (AUC0-∞) value 4.591 ± 0.163 µg/ml x h, elimination half-life (T1/2) 6.28 ± 0.71 h and elimination rate constant was found 0.110 ± 0.013 h-1 . Above evidences indicate that QS11 could serve as a lead for development of new antiepileptic drugs.

Gamma-aminobutyric acidergic transmission underlies interictal epileptogenicity in pediatric focal cortical dysplasia.

Dysregulation of γ-aminobutyric acidergic (GABAergic) transmission has been reported in lesional acquired epilepsies (gliomas, hippocampal sclerosis). We investigated its involvement in a developmental disorder, human focal cortical dysplasia (FCD), focusing on chloride regulation driving GABAergic signals. In vitro recordings of 47 human cortical acute slices from 11 pediatric patients who received operations for FCD were performed on multielectrode arrays. GABAergic receptors and chloride regulators were pharmacologically modulated. Immunostaining for chloride cotransporter KCC2 and interneurons were performed on recorded slices to correlate electrophysiology and expression patterns. FCD slices retain intrinsic epileptogenicity. Thirty-six of 47 slices displayed spontaneous interictal discharges, along with a pattern specific to the histological subtypes. Ictal discharges were induced in proepileptic conditions in 6 of 8 slices in the areas generating spontaneous interictal discharges, with a transition to seizure involving the emergence of preictal discharges. Interictal discharges were sustained by GABAergic signaling, as a GABAA receptor blocker stopped them in 2 of 3 slices. Blockade of NKCC1 Cl- cotransporters further controlled interictal discharges in 9 of 12 cases, revealing a Cl- dysregulation affecting actions of GABA. Immunohistochemistry highlighted decreased expression and changes in KCC2 subcellular localization and a decrease in the number of GAD67-positive interneurons in regions generating interictal discharges. Altered chloride cotransporter expression and changes in interneuron density in FCD may lead to paradoxical depolarization of pyramidal cells. Spontaneous interictal discharges are consequently mediated by GABAergic signals, and targeting chloride regulation in neurons may be considered for the development of new antiepileptic drugs. Ann Neurol 2019; 1-14 ANN NEUROL 2019;85:204-217.

Epidemiology of drug resistant epilepsy in adults

This review examines the epidemiology of drug resistant epilepsy in adults in Russia and abroad. References were taken from Russian and foreign databases for the period from 2010–2017. Only full-text publications (66) were included in this review. We concluded that the despite the achievements of clinical pharmacology and the development of new antiepileptic drugs, the problem of drug resistant epilepsy remains not fully resolved today. The worldwide high prevalence rate of patients with drug resistant epilepsy substantiates the problem. Thus, the average incidence of this disease varies from 30% to 70%, depending on the type of epilepsy and background pathology, which is the cause of symptomatic epilepsy. However, we have faced the problem of the absence both in Russia and abroad of large multicenter studies on the epidemiology of drug resistant epilepsy in the analyzed period of time. We have also revealed the lack of a unified definition of the disease, which is probably one of the reasons for the insufficient number of epidemiological studies of drug resistant epilepsy in different countries of the world.

Voltage-Dependent Calcium Channels, Calcium Binding Proteins, and Their Interaction in the Pathological Process of Epilepsy.

As an important second messenger, the calcium ion (Ca2+) plays a vital role in normal brain function and in the pathophysiological process of different neurodegenerative diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), and epilepsy. Ca2+ takes part in the regulation of neuronal excitability, and the imbalance of intracellular Ca2+ is a trigger factor for the occurrence of epilepsy. Several anti-epileptic drugs target voltage-dependent calcium channels (VDCCs). Intracellular Ca2+ levels are mainly controlled by VDCCs located in the plasma membrane, the calcium-binding proteins (CBPs) inside the cytoplasm, calcium channels located on the intracellular calcium store (particular the endoplasmic reticulum/sarcoplasmic reticulum), and the Ca2+-pumps located in the plasma membrane and intracellular calcium store. So far, while many studies have established the relationship between calcium control factors and epilepsy, the mechanism of various Ca2+ regulatory factors in epileptogenesis is still unknown. In this paper, we reviewed the function, distribution, and alteration of VDCCs and CBPs in the central nervous system in the pathological process of epilepsy. The interaction of VDCCs with CBPs in the pathological process of epilepsy was also summarized. We hope this review can provide some clues for better understanding the mechanism of epileptogenesis, and for the development of new anti-epileptic drugs targeting on VDCCs and CBPs.

Anticonvulsant-like effect of thromboxane receptor agonist U-46619 against pentylenetetrazol-induced seizures

Increasing evidence suggests that prostanoid receptors and their ligands may constitute valuable tools for development of new antiepileptic drugs. Thromboxane A2 (TXA2) is a major eicosanoid in cardiovascular homeostasis. TXA2 exerts its action through the specific G protein-coupled TXA2 receptor (TP). In addition to its crucial role in the cardiovascular system, TXA2 and TPs play a role in the brain. Nevertheless, previously identified roles have been limited to cell protection of neurotoxicity, and the role of TPs on seizure activity was not investigated. Here we evaluated the effect of potent and selective TP agonist U-46619 on seizures induced by pentylenetetrazol (PTZ). Adult C57BL/6 mice received increasing doses of U-46619 (0, 30, 100 or 300 μg/kg). After 30 min we measured the latencies to myoclonic and generalized seizures induced by PTZ (60 mg/kg). We found that U-46619 increased the latency to PTZ-induced myoclonic jerks and tonic-clonic seizures. Moreover, U-46619 increased the immunocontent of phosphorylated Ser657 at protein kinase C (PKC) alpha subunit, indicating PKC activation in the hippocampus and cerebral cortex. Levels of TPs were not altered by the agonist. Administration of a TP antagonist, SQ 29,548, did not alter seizures and did not blunt the anticonvulsant-like effect of the agonist. In summary, we showed that a potent and selective TP agonist, U-46619, increased seizure latency in mice. Activation of PKC signaling pathways may underlie the anticonvulsant-like effect. Further investigation is needed to understand the potential of TPs in seizure treatment.