Development Of New Antiepileptic Drugs Research Articles

Effects of gap junctions blockers on fast ripples and connexin in rat hippocampi after status epilepticus

ObjectiveTo assess the dynamic changes in the average and peak spectral power of fast ripples (FRs) in the hippocampi after interventions with valproate sodium (VPA), carbenoxolone (CBX) and quinine (QUIN). MethodAdult rats were used to establish a lithium–pilocarpine (pilo) epileptic model, and were assigned to a lithium–pilocarpine (PILO), VPA + PILO, QUIN + PILO or CBX + PILO group. Intracranial electroencephalography was performed before and after status epilepticus (SE). The hippocampal connexin (CX) 43, CX32 and CX36 expressions were analyzed via western blotting. ResultsThe time required for the disappearance of SE after chloral hydrate injection was lower in the intervention groups than in the PILO group (p < 0.05). Seizures induced CX43 expression, but had no significant effects on CX36 or CX32 expressions. Pretreatment with VPA, QUIN and CBX inhibited CX43, CX36 and CX32 expression after SE. The average spectral power of the FRs was significantly lower in the VPA + PILO and QUIN + PILO groups than in the PILO group at 10 min after SE, 10 min before chloral hydrate injection, and 10 min after chloral hydrate injection (p < 0.05). The average spectral power of FRs was lower in the CBX + PILO group than in the PILO group at 10 min after SE (p < 0.05). The average spectral power of FRs in the 3 intervention groups recovered to the baseline level at 10 min after chloral hydrate injection and persisted for 3 days after SE. The dynamic changes in the average and peak spectral power of FRs were similar. SignificanceAfter SE, CX may participate in pathological FR generation by establishing abnormal electrical synaptic transmission. Gap junction blockers can inhibit various CX expressions, and thus decrease FR energy and alleviate the degree of seizure. These findings could contribute to the development of new anti-epileptic drugs with novel mechanistic targets.

Electrical Control in Neurons by the Ketogenic Diet.

The ketogenic diet is used as a diet treatment for drug-resistant epilepsy, but there are no antiepileptic drugs based on the ketogenic diet. The ketogenic diet changes energy metabolites (ketone bodies, glucose and lactate) in the brain, which consequently changes electrical activities in neurons and ultimately suppresses seizures in epileptic patients. In order to elucidate the antiseizure effects of the ketogenic diet, it is important to clarify the mechanism by which these metabolic changes are converted to electrical changes in neurons. In this review, we summarize electrophysiological studies focusing on electrical control in neurons by the ketogenic diet. Recent studies have identified electrical regulators driven by the ketogenic diet: ion channels (ATP-sensitive K+ channels and voltage-dependent Ca2+ channels), synaptic receptors (AMPA-type glutamate receptors and adenosine A1 receptors), neurotransmitter transporters (vesicular glutamate transporters), and others (BCL-2-associated agonist of cell death and lactate dehydrogenase). Thus, the ketogenic diet presumably elicits neuronal inhibition via the combined actions of these molecules. From the viewpoint of drug development, these molecules are valuable as targets for the development of new antiepileptic drugs. Drug therapy to mimic the ketogenic diet may be feasible in the future, through the combination of multiple antiepileptic drugs targeting these molecules.

Forebrain glutamate uptake and behavioral parameters are altered in adult zebrafish after the induction of Status Epilepticus by kainic acid

The development of new antiepileptic drugs is a high-risk/high-cost research field, which is made even riskier if the behavioral epileptic seizure profile is the unique approach on which the development is based. In order to increase the effectiveness of the screening conducted in the zebrafish model of status epilepticus (SE), the evaluation of neurochemical markers of SE would be of great relevance. Epilepsy is associated with changes in the glutamatergic system, and glutamate uptake is one of the critical parameters of this process. Therefore, we evaluated the levels of glutamate uptake in the zebrafish brain and analyzed its correlation with the progression of behavioral changes in zebrafish at different times after the administration of kainic acid (5 mg/kg). The results showed that the zebrafish suffered with lethargy while swimming for up to 72 h after SE, had reduced levels of GFAP cells 12 h after SE, reduced levels of S100B up to 72 h after SE, and reduced levels of glutamate uptake in the forebrain between 3 h and 12 h after SE. The forebrain region of adult zebrafish after SE present similar changes to the neurochemical limbic alterations that are seen in rodent models of SE. This study demonstrated that there is a time window in which to use the KA zebrafish model of SE to explore some of the known neurochemical alterations that have been observed in rodent models of epilepsy and epileptic human patients.

The Metabotropic Purinergic P2Y Receptor Family as Novel Drug Target in Epilepsy.

Epilepsy encompasses a heterogeneous group of neurological syndromes which are characterized by recurrent seizures affecting over 60 million people worldwide. Current anti-epileptic drugs (AEDs) are mainly designed to target ion channels and/or GABA or glutamate receptors. Despite recent advances in drug development, however, pharmacoresistance in epilepsy remains as high as 30%, suggesting the need for the development of new AEDs with a non-classical mechanism of action. Neuroinflammation is increasingly recognized as one of the key players in seizure generation and in the maintenance of the epileptic phenotype. Consequently, targeting signaling molecules involved in inflammatory processes may represent new avenues to improve treatment in epilepsy. Nucleotides such as adenosine-5′-triphosphate (ATP) and uridine-5′-triphosphate (UTP) are released in the brain into the extracellular space during pathological conditions such as increased neuronal firing or cell death. Once released, these nucleotides bind to and activate specific purinergic receptors termed P2 receptors where they mediate the release of gliotransmitters and drive neuronal hyperexcitation and neuroinflammatory processes. This includes the fast acting ionotropic P2X channels and slower-acting G-protein-coupled P2Y receptors. While the expression and function of P2X receptors has been well-established in experimental models of epilepsy, emerging evidence is now also suggesting a prominent role for the P2Y receptor subfamily in seizure generation and the maintenance of epilepsy. In this review we discuss data supporting a role for the P2Y receptor family in epilepsy and the most recent finding demonstrating their involvement during seizure-induced pathology and in epilepsy.

The ATP-Gated P2X7 Receptor As a Target for the Treatment of Drug-Resistant Epilepsy.

Despite the progress made in the development of new antiepileptic drugs (AEDs), the biggest challenges that epilepsy presents to drug development have remained unchanged for the last 80 years: finding a treatment with potential for modifying disease progression and reducing the percentage of patients resistant to all pharmacological interventions. The mechanism of action of the majority of AEDs is based on blocking Na+ and/or Ca2+ channels, promotion of GABA or inhibition of glutamate signaling. In order for further progress to be made, however, a fuller picture of epilepsy will need to be considered, including changes to blood–brain barrier permeability, synaptic plasticity, network reorganization, and gliosis. In particular, brain inflammation has attracted much attention over recent years. Emerging evidence demonstrates a causal role for brain inflammation in lowering seizure thresholds and driving epileptogenesis. Consistent with this, intervening in pro-inflammatory cascades has shown promise in animal models of epilepsy, with clinical trials of anti-inflammatory agents already underway. The ATP-gated purinergic P2X7 receptor (P2X7) has been proposed as a novel drug target for a host of neurological conditions, including epilepsy. Constitutive expression of P2X7 in the CNS is mainly on microglia, but neuronal and astroglial expression has also been suggested. Its function as a gatekeeper of inflammation is most clearly understood, however, it also plays a number of other important roles pertinent to icto- and epileptogenesis: depolarization of the cell membrane, release of macromolecules, induction of apoptosis and synaptic reorganization. Changes in P2X7 expression have been reported following prolonged seizures (status epilepticus) and during chronic epilepsy in both experimental models and patients. While much of the early work focused on the study of P2X7 during status epilepticus, there is now mounting data showing involvement of this receptor during epilepsy. The present short review will discuss the most recent findings concerning P2X7 expression and function during epilepsy and the clinical potential for P2X7 antagonists as novel AEDs.

Perampanel in the treatment of patients with epilepsy

Development of new antiepileptic drugs (AED) does not stop due to the fact that the number of patients with pharmacoresistant epilepsy remains at about 30%. One of the newest AEDs is perampanel (PER), a selective, non-competitive AMPA receptor antagonist to target post-synaptic glutamate transmission. PER is approved in the Russian Federation as adjunctive treatment for focal seizures with or without secondarily generalized seizures and for primary generalized tonic-clonic (PGTC) seizures in idiopathic generalized epilepsy (IGE) in patients with epilepsy aged ≥12 years. The drug is effective and well-tolerated in the dose of 4-8 mg/day, and most side effects are dose-dependent. The high efficacy of PER combined with the good tolerability, absence of life-threatening adverse reactions and convenient intake allow us to recommend PER as the first choice additional drug in treatment of patients with epilepsy.

Recent Developments of Hydrazide/Hydrazone Derivatives and Their Analogs as Anticonvulsant Agents in Animal Models.

Preclinical Research Epilepsy is a chronic devastating neurological disorder characterized by synchronous interictal discharges. Treatment with antiepileptic drugs (AEDs) can alleviate spontaneous seizure activity without preventing the progression and development of epileptogenesis. Current design and development of new AEDs and strategies for the prevention of epilepsy is focused mainly on attenuating uncontrolled seizures, severe side effects and toxicity in chronic drug therapy. It has thus become necessary to discover new chemical pharmacophores with a broad spectrum of activity and less neurotoxicity. Hydrazide/hydrazone derivatives that possess a -CO-NHN=CH- group constitute an important class of compounds for drug development. This review highlights the specific characteristics of various hydrazide/hydrazone derivatives and structurally related semicarbazones, semicarbazides and Schiff base compounds and their anticonvulsant activities. It is focused on the influence of differently substituted pharmacophores developed through SAR studies and testing their activity against different pharmcological targets. Drug Dev Res 77 : 379-392, 2016. © 2016 Wiley Periodicals, Inc.

Disease Course, Outcome Measures, and Prognostic Predictors in Epilepsy: Opportunities for Improving Outcome of Drug Trials.

A major concern over the development of new antiepileptic drugs (AEDs) is that the new AEDs have not added substantial clinical benefit over available antiseizure treatment. Additionally, current AEDs have neither improved the health of epilepsy patients nor been shown to prevent epilepsy or to improve the disease. This chapter reviews new data on patterns of epilepsy with remission and relapse, prognostic factors for seizure outcome, and innovative patient-related outcome measures. Applying this knowledge presents opportunities to improve the drug treatment of epilepsy. Patient-relevant outcome measures and trial designs may be optimized to provide both evidence for efficacy and safety of AEDs and, in addition, for added clinical benefit over existing treatment. Added benefit of a new AED may be shown by evidence of higher antiseizure efficacy, better health, shorter disease duration, fewer side effects, and improved quality of life compared to available standard treatment. Moving from largely patient-irrelevant outcome measures such as 50% seizure reduction or use of placebo controls to innovative comparison of new AEDs versus standard treatment will revitalize the clinical development of new antiseizure treatments. Hopefully this will usher in a new era of much-needed antiepileptogenic agents that prevent or improve the patterns of epilepsy.

Modulation of brain glutamate dehydrogenase as a tool for controlling seizures.

Glutamate (Glu) is a major excitatory neurotransmitter involved in epilepsy. Glu is synthesized by glutamate dehydrogenase (GDH, E.C. 1.4.1.3) and dysfunction of the enzymatic activity of GDH is associated with brain pathologies. The main goal of this work is to establish the role of GDH in the effects of antiepileptic drugs (AEDs) such as valproate (VALP), diazepam (DIAZ) and diphenylhydantoin (DPH) and its repercussions on oxygen consumption. Oxidative deamination of Glu and reductive amination of αketoglutarate (αK) in mice brain were investigated. Our results show that AEDs decrease GDH activity and oxygen consumption in vitro. In ex vivo experiments, AEDs increased GDH activity but decreased oxygen consumption during Glu oxidative deamination. VALP and DPH reversed the increase in reductive amination of αK caused by the chemoconvulsant pentylenetetrazol. These results suggest that AEDs act by modulating brain GDH activity, which in turn decreased oxygen consumption. GDH represents an important regulation point of neuronal excitability, and modulation of its activity represents a potential target for metabolic treatment of epilepsy and for the development of new AEDs.

Reduced estradiol synthesis by letrozole, an aromatase inhibitor, is protective against development of pentylenetetrazole-induced kindling in mice

Neurosteroids, such as testosterone and their metabolites, are known to modulate neuronal excitability. The enzymes regulating the metabolism of these neurosteroids, thus, may be targeted as a noval strategy for the development of new antiepileptic drugs. The present work targeted two such enzymes i,e aromatase and 5α-reductase in order to explore the potential of letrozole (an aromatase inhibitor) on pentylenetetrazole (PTZ)-induced kindling in mice and the ability of finasteride (a 5α-reductase inhibitor) to modulate any such effects. PTZ (30 mg/kg, i.p.), when administered once every two days (for a total of 24 doses) induced kindling in Swiss albino mice. Letrozole (1 mg/kg, p.o.), administered prior to PTZ, significantly reduced the % incidence of kindling, delayed mean onset time of seizures and reduced seizure severity score. Letrozole reduced the levels of plasma 17β-estradiol after induction of kindling. The concurrent administration of finasteride and letrozole produced effects similar to letrozole on PTZ-kindling and on estradiol levels. This implies that the ability of letrozole to redirect the synthesis of dihydrotestosterone (DHT) and 5α-androstanediol from testosterone doesn't appear to play a significant role in the protective effects of letrozole against PTZ kindling. Letrozole, however, increased the levels of 5α-DHT in mice plasma. The aromatase inhibitors, thus, may be exploited for inhibiting the synthesis of proconvulsant (17β-estradiol) and/or redirecting the synthesis of anticonvulsant (DHT and 5α-androstanediol) neurosteroids.

Pro- and Anticonvulsant Effects of the Ant Dinoponera quadriceps (Kempf) Venom in Mice.

Epilepsy affects at least 50 million people worldwide, and the available treatment is associated with various side effects. Approximately 20-30% of the patients develop seizures that persist despite careful monitored treatment with antiepileptic drugs. Thus, there is a clear need for the development of new antiepileptic drugs, and the venoms can be an excellent source of probes. In this context, while there are studies on venoms from snakes, scorpions, and spiders, little is known regarding venom from ants. The aim of this study was to investigate the potential pro- and anticonvulsant effects of the venom from the ant Dinoponera quadriceps (Kempf) in Swiss mice. After the injection of the crude venom (DqTx-5, 50, and 500mg/mL) in the lateral ventricle of mice, we observed a reduction of exploration and grooming behaviors, as well as an increase in immobility duration. In addition, the crude venom induced procursive behavior and tonic-clonic seizures at the highest concentration. Conversely, the preadministration of the denatured venom (AbDq) at the concentration of 2mg/mL protected the animals against tonic-clonic seizures (66.7%) and death (100%) induced by administration of bicuculline. Taken together, the findings demonstrate that D. quadriceps venom might be potential source of new pro- and anticonvulsants molecules.

Pentylenetetrazol Kindling Epilepsy Model

Epilepsy is one of the most common neurologic disorders affecting approximately 1% of the general population, and no alleviation was achieved in one third of the patients medicated with antiepileptic drugs. Current treatments of epilepsy are symptomatic and have more anti-seizure effects than antiepileptic effects. These therapies do not cure epilepsy. Basic mechanisms of epilepsy have not entirely been clarified yet. Using seizure and epilepsy animal models, our comprehension about basic mechanisms underlying epileptogenesis has improved. In addition, animal models of epilepsy and seizures are very useful in the discovery and development of new antiepileptic drugs. Pentylenetetrazole (PTZ) is widely used in antiepileptic drug discovery studies, and PTZ kindling model is very important to understand the pathophysiology of epilepsy. In this review, current information about PTZ kindling model was given in this aspect.

Low threshold T‐type calcium channels as targets for novel epilepsy treatments

Low voltage-activated T-type calcium channels were originally cloned in the 1990s and much research has since focused on identifying the physiological roles of these channels in health and disease states. T-type calcium channels are expressed widely throughout the brain and peripheral tissues, and thus have been proposed as therapeutic targets for a variety of diseases such as epilepsy, insomnia, pain, cancer and hypertension. This review discusses the literature concerning the role of T-type calcium channels in physiological and pathological processes related to epilepsy. T-type calcium channels have been implicated in pathology of both the genetic and acquired epilepsies and several anti-epileptic drugs (AEDs) in clinical use are known to suppress seizures via inhibition of T-type calcium channels. Despite the fact that more than 15 new AEDs have become clinically available over the past 20 years at least 30% of epilepsy patients still fail to achieve seizure control, and many patients experience unwanted side effects. Furthermore there are no treatments that prevent the development of epilepsy or mitigate the epileptic state once established. Therefore there is an urgent need for the development of new AEDs that are effective in patients with drug resistant epilepsy, are anti-epileptogenic and are better tolerated. We also review the mechanisms of action of the current AEDs with known effects on T-type calcium channels and discuss novel compounds that are being investigated as new treatments for epilepsy.

Calcium signaling and epilepsy.

Calcium signaling is involved in a multitude of physiological and pathophysiological mechanisms. Over the last decade, it has been increasingly recognized as an important factor in epileptogenesis, and it is becoming obvious that the excess synchronization of neurons that is characteristic for seizures can be linked to various calcium signaling pathways. These include immediate effects on membrane excitability by calcium influx through ion channels as well as delayed mechanisms that act through G-protein coupled pathways. Calcium signaling is able to cause hyperexcitability either by direct modulation of neuronal activity or indirectly through calcium-dependent gliotransmission. Furthermore, feedback mechanisms between mitochondrial calcium signaling and reactive oxygen species are able to cause neuronal cell death and seizures. Unravelling the complexity of calcium signaling in epileptogenesis is a daunting task, but it includes the promise to uncover formerly unknown targets for the development of new antiepileptic drugs.

Neuropeptides as Targets for the Development of Anticonvulsant Drugs

Epilepsy is a common neurological disorder characterized by recurrent seizures. These seizures are due to abnormal excessive and synchronous neuronal activity in the brain caused by a disruption of the delicate balance between excitation and inhibition. Neuropeptides can contribute to such misbalance by modulating the effect of classical excitatory and inhibitory neurotransmitters. In this review, we discuss 21 different neuropeptides that have been linked to seizure disorders. These neuropeptides show an aberrant expression and/or release in animal seizure models and/or epilepsy patients. Many of these endogenous peptides, like adrenocorticotropic hormone, angiotensin, cholecystokinin, cortistatin, dynorphin, galanin, ghrelin, neuropeptide Y, neurotensin, somatostatin, and thyrotropin-releasing hormone, are able to suppress seizures in the brain. Other neuropeptides, such as arginine-vasopressine peptide, corticotropin-releasing hormone, enkephalin, β-endorphin, pituitary adenylate cyclase-activating polypeptide, and tachykinins have proconvulsive properties. For oxytocin and melanin-concentrating hormone both pro- and anticonvulsive effects have been reported, and this seems to be dose or time dependent. All these neuropeptides and their receptors are interesting targets for the development of new antiepileptic drugs. Other neuropeptides such as nesfatin-1 and vasoactive intestinal peptide have been less studied in this field; however, as nesfatin-1 levels change over the course of epilepsy, this can be considered as an interesting marker to diagnose patients who have suffered a recent epileptic seizure.

Childhood Epilepsy: An Update on Diagnosis and Management

Within the past few years there is a rapid expansion in our understanding of epilepsy. The development of new anti-epileptic drugs and refinements to epilepsy surgery are widening the therapeutic options for epilepsy. In addition, the classification of the epilepsies continues to evolve based on an increased understanding of the molecular genetics of the condition and this includes the recognition of possible novel epilepsy syndromes. This review considers some of these exciting developments, as well as addressing the essential features of the diagnosis, investigations, management and impact of epilepsy in childhood.

Structure Activity Relationships of Novel Antiepileptic Drugs

Despite notable success over years in the discovery and development of new antiepileptic drugs (AEDs), about 30-40% of the patients are resistant to drug treatment. There is a still significant need to develop novel AEDs that demonstrate superior efficacy, broad spectrum of activities and good safety profile. The synaptic vesicle glycoprotein 2A (SV2A), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-R) and voltage-gated potassium channels (KCNQ2/Q3) are clinically validated as new molecular targets for epilepsy. The discovery of SV2A as a target for levetiracetam, 2,3-benzodiazepine GYKI 52466 as a non-competitive AMPA-R antagonist and retigabine as a KCNQ2/Q3 channels activator provided a rational basis to develop novel AEDs. The optimization of SV2A binding affinity of levetiracetam led to the discovery of novel high affinity SV2A ligands that displayed superior efficacy and protective index in animal models of epilepsy. The high-throughput screening (HTS) and medicinal chemistry efforts yielded many non-competitive AMPA-R antagonists of which perampanel was recently approved as a first-in-a new class. The efficacy and lack of sub-type selectivity of retigabine prompted many research efforts to discover several potent and selective KCNQ2/Q3 channel activators of distinct chemical scaffolds that are at various stages of clinical development. Despite the known role of galanin and galanin receptor (Gal-R) in epilepsy over a decade, development of potent and brainpenetrant Gal-R agonists is very challenging. The discovery of selective Gal-R2 positive allosteric modulator, CYM 2503, offers a valuable and an alternative approach. The review focuses on the available structure-activity relationships and preclinical efficacy of novel antiepileptic compounds that are distinct from most of the approved AEDs, specifically SV2A ligands, non-competitive AMPA-R antagonists, KCNQ2/Q3 channels activators and Gal-R modulators.

Role of inflammatory mediators in the pathogenesis of epilepsy.

Epilepsy is one of the most common chronic brain disorders worldwide, affecting 1% of people across different ages and backgrounds. Epilepsy is defined as the sporadic occurrence of spontaneous recurrent seizures. Accumulating preclinical and clinical evidence suggest that there is a positive feedback cycle between epileptogenesis and brain inflammation. Epileptic seizures increase key inflammatory mediators, which in turn cause secondary damage to the brain and increase the likelihood of recurrent seizures. Cytokines and prostaglandins are well-known inflammatory mediators in the brain, and their biosynthesis is enhanced following seizures. Such inflammatory mediators could be therapeutic targets for the development of new antiepileptic drugs. In this review, we discuss the roles of inflammatory mediators in epileptogenesis.

Pilocarpine-induced epilepsy in mice alters seizure thresholds and the efficacy of antiepileptic drugs in the 6-Hertz psychomotor seizure model

The 6-Hz psychomotor seizure model in mice is increasingly been used as a model for differentiation of anticonvulsant activity during development of new antiepileptic drugs (AEDs). It was previously proposed as a useful model of AED-resistant seizures, but more recent data have cast doubt on this proposal. The aim of the present study was to determine whether performing the 6-Hz test not in normal but epileptic mice renders the 6-Hz test more resistant to AEDs. Furthermore, thresholds for induction of 6-Hz seizures, maximal electroshock seizures (MES) and pentylenetetrazole (PTZ) seizures were compared in normal and epileptic mice, using the pilocarpine model. Epileptic mice had a significantly lower threshold for induction of 6-Hz seizures and were more susceptible to PTZ, whereas the MES threshold was not altered. Unexpectedly, 6-Hz seizures were not more resistant to AEDs in epileptic vs. nonepileptic mice, but instead showed an increased sensitivity to the anticonvulsant effects of some AEDs, particularly levetiracetam. The anticonvulsant ED50 of levetiracetam in the 6-Hz test (using a 32mA stimulus) was 17.6mg/kg in nonepileptic mice, but only 1.5mg/kg in epileptic mice. The data indicate that the complex pathophysiological and functional alterations associated with epilepsy in mice may strikingly alter the sensitivity of acutely induced seizures to an AED.

A novel kindling model of temporal lobe epilepsy in rhesus monkeys induced by Coriaria lactone

One of the major challenges in developing novel therapeutics for human epileptic disorders derives from the limitation of knowledge of the processes by which epilepsy is generated (epileptogenesis). Furthermore, the inability to obtain human samples at the early stage of epilepsy hinders studies designed to further understand epileptogenesis. Thus, an effective animal model is critical for studies investigating this process. The purpose of this study was to establish a new primate kindling model of temporal lobe epilepsy (TLE) as an animal model of epileptogenesis. Here, repeated injections of Coriaria lactone (CL) at a subthreshold dose elicited partial seizures that culminated in secondarily generalized tonic–clonic seizures. The sequence of events and features of the behaviors observed in this model simulated those observed in human TLE. Electroencephalogram monitoring revealed the temporal lobe origins of the epileptiform potentials, which were consistent with the behavioral changes observed. A total of 7 rhesus monkeys (78%) were kindled with a median of 48 (41 to 60) CL injections. Both the seizure-induction and mortality rates were dose-dependent. A CL injection at 1.50mg/kg showed the lowest animal mortality rate (0%) and the highest seizure-induction rate (100%). Extensive kindling by CL injections with a median of 97 injections (overkindling) subsequently resulted in the recurrence of spontaneous seizures in rhesus monkeys with frequency patterns that were similar to those observed in human TLE. In addition, rhesus monkeys subjected to large numbers of kindling stimuli displayed mitochondrial damage and astrocyte activation in a pattern that was similar to the neuropathological changes characteristic of human TLE. Thus, a kindling TLE model in rhesus monkeys representing a primate animal model of epileptogenesis was established for the first time using repeated intramuscular injections of Coriaria lactone. This model was easily and efficiently performed and resulted in behavioral, electrographical, and anatomical characteristics of human TLE. Thus, this model might be used in future investigations of the mechanisms involved in the epileptogenesis of TLE and in the development of new antiepileptic drugs.