五种与癫癎治疗靶点相关蛋白质在颞叶癫癎模型海马组织中的表达

目的寻找颞叶癫大鼠海马组织的差异表达蛋白质,为寻找新的癫治疗靶点和研发新的治疗手段打下基础。方法运用二维电泳和MALD I-TOF-MS技术,对比分析氯化锂-匹罗卡品致大鼠海马组织和正常大鼠海马组织的蛋白质表达谱,对发现的差异表达蛋白质进行分析和鉴定。结果在氯化锂-匹罗卡品致大鼠海马组织中筛选到32个差异表达蛋白质斑点,其中20个在癫组表达下调,12个在癫组表达上调,其中5个蛋白质已被最终鉴定确认,分别为:突触结合蛋白Ⅰ(synaptotagm inⅠ)、神经丝蛋白(neurofilam ents,NF)、热休克蛋白27(heat shock prote in 27,HSP27)、电压依赖性阴离子通道1(voltage-dependent an ion channel prote ins 1,VDAC1)和异柠檬酸脱氢酶(isoc itric dehydrogenase,ICD),其中突触结合蛋白Ⅰ可能为潜在的新治疗靶点。结论颞叶癫大鼠海马组织中存在大量差异表达蛋白质,部分可能为潜在的癫治疗靶点。     

Enhanced expression of the voltage-dependent anion channel 1 (VDAC1) in Alzheimer's disease transgenic mice: an insight into the pathogenic effects of amyloid-β

The mitochondrial voltage-dependent anion channel 1 (VDAC1) is involved in the release of apoptotic proteins with possible relevance in Alzheimer's disease (AD) neuropathology. Through proteomic analysis followed by Western blotting and immunohistochemical techniques, we have found that VDAC1 is overexpressed in the hippocampus from amyloidogenic AD transgenic mice models. VDAC1 was also overexpressed in postmortem brain tissue from AD patients at an advanced stage of the disease. Interestingly, amyloid-β (Aβ) soluble oligomers were able to induce upregulation of VDAC1 in a human neuroblastoma cell line, further supporting a correlation between Aβ levels and VDAC1 expression. In hippocampal extracts from transgenic mice, a significant increase was observed in the levels of VDAC1 phosphorylated at an epitope that is susceptible to phosphorylation by glycogen synthase kinase-3β, whose activity was also increased. The levels of hexokinase I (HXKI), which interacts with VDAC1 and affects its function, were decreased in mitochondrial samples from AD models. Since phospho-VDAC and reduced HXKI levels favors a VDAC1 conformational state more prone to the release proapoptotic factors, regulation of the function of this channel may be a promising therapeutic approach to combat AD.     

Developing novel antiepileptic drugs: Characterization of NAX 5055, a systemically-active galanin analog, in epilepsy models

The endogenous neuropeptide galanin and its associated receptors galanin receptor 1 and galanin receptor 2 are highly localized in brain limbic structures and play an important role in the control of seizures in animal epilepsy models. As such, galanin receptors provide an attractive target for the development of novel anticonvulsant drugs. Our efforts to engineer galanin analogs that can penetrate the blood-brain-barrier and suppress seizures, yielded NAX 5055 (Gal-B2), a systemically-active analog that maintains low nanomolar affinity for galanin receptors and displays a potent anticonvulsant activity. In this report, we show that NAX 5055 is active in three models of epilepsy: 1) the Frings audiogenic seizure-susceptible mouse, 2) the mouse corneal kindling model of partial epilepsy, and 3) the 6 Hz model of pharmacoresistant epilepsy. NAX 5055 was not active in the traditional maximal electroshock and subcutaneous pentylenetetrazol seizure models. Unlike most antiepileptic drugs, NAX 5055 showed high potency in the 6 Hz model of epilepsy across all three different stimulation currents; i.e., 22, 32 and 44 mA, suggesting a potential use in the treatment of pharmacoresistant epilepsy. Furthermore, NAX 5055 was found to be biologically active after intravenous, intraperitoneal, and subcutaneous administration, and efficacy was associated with a linear pharmacokinetic profile. The results of the present investigation suggest that NAX 5055 is a first-in-class neurotherapeutic for the treatment of epilepsy in patients refractory to currently approved antiepileptic drugs.     

Adenosine-based cell therapy approaches for pharmacoresistant epilepsies

Despite recent medical advances pharmacoresistant epilepsy continues to be a major health problem. The knowledge of endogenous protective mechanisms of the brain may lead to the development of rational therapies tailored to a patient's needs. Adenosine has been identified as an endogenous neuromodulator with antiepileptic and neuroprotective properties. However, the therapeutic use of adenosine or its receptor agonists is largely precluded by strong peripheral and central side effects. Thus, local delivery of adenosine to a critical site of the brain may provide a solution for the therapeutic use of adenosine. The following rationale for the local augmentation of the adenosine system as a novel therapeutic principle in the treatment of epilepsy has been established: (1) Deficits in the adenosinergic system are associated with epileptogenesis and these deficits promote seizures. Thus, reconstitution of an inhibitory adenosinergic tone is a rational therapeutic approach. (2) The focal paracrine delivery of adenosine from encapsulated cells suppresses seizures in kindled rats without overt side effects. (3) The anticonvulsant activity of locally released adenosine is maintained in models of epilepsy which are resistant to major antiepileptic drugs. This review summarizes the rationale and recent approaches for adenosine-based cell therapies for pharmacoresistant epilepsies.     

Predictors of pharmacoresistant epilepsy: pharmacoresistant rats differ from pharmacoresponsive rats in behavioral and cognitive abnormalities associated with experimentally induced epilepsy

Purpose: Patients with intractable temporal lobe epilepsy (TLE) exhibit an increased risk of psychiatric comorbidity, including depression, anxiety, psychosis, and learning disorders. Furthermore, a history of psychiatric comorbidity has been suggested as a predictor of lack of response to therapy with antiepileptic drugs (AEDs) in patients with epilepsy. However, clinical studies on predictors of pharmacoresistant epilepsy are affected by several confounding variables, which may complicate conclusions. In the present study, we evaluated whether behavioral alterations in epileptic rats are different in AED nonresponders versus responders. Methods: For this purpose, we used an animal model of TLE in which AED responders and nonresponders can be selected by prolonged treatment of epileptic rats with phenobarbital (PB). Behavioral and cognitive abnormalities were compared between responders and nonresponders as well as between epileptic rats and nonepileptic controls in a battery of tests. Results: Fifteen epileptic rats with spontaneous recurrent seizures (SRS) either responding (11 rats) or not responding (4 rats) to PB were used for this study. The nonresponders differed markedly in behavioral and cognitive abnormalities from responders and nonepileptic controls in tests of anxiety (open field, elevated‐plus maze test), behavioral hyperexcitability (approach‐response, touch‐response, pick‐up tests), and learning and memory (Morris water maze). Discussion: Our hypothesis that AED‐resistant rats will show more severe behavioral and cognitive changes than AED‐responsive rats was confirmed by the present experiments. The data substantiate that rodent models of TLE are useful to delineate predictors of pharmacoresistant epilepsy.     

An epilepsy mutation in the beta1 subunit of the voltage-gated sodium channel results in reduced channel sensitivity to phenytoin

The antiepileptic drug phenytoin inhibits voltage-gated sodium channels. Phenytoin block is enhanced at depolarized membrane potentials and during high frequency channel activation. These properties, which are important for the clinical efficacy of the drug, depend on voltage-dependent channel gating. In this study, we examined the action of phenytoin on sodium channels, comprising a mutant auxiliary beta1 subunit (mutation C121Wbeta1), which causes the inherited epilepsy syndrome, generalized epilepsy with febrile seizures plus (GEFS+). Whole cell sodium currents in Chinese hamster ovary (CHO) cells coexpressing human Na(v)1.3 sodium channels and C121Wbeta1 exhibited altered gating properties, compared to currents in cells coexpressing Na(v)1.3 and wild type beta1. In addition mutant channels were less sensitive to inhibition by phenytoin, showing reduced tonic block at -70mV (EC(50)=26microM for C121Wbeta1 versus 11microM for wild type beta1) and less frequency-dependent inhibition in response to a 20Hz pulse train ( approximately 40% inhibition for C121Wbeta1 versus approximately 70% inhibition for wild type beta1, with 50microM phenytoin). Mutant and wild type channels did not differ in inactivated state affinity for phenytoin, suggesting that their pharmacological differences were secondary to their differences in voltage-dependent gating, rather than being caused by direct effects of the mutation on the drug receptor. Together, these data show that a sodium channel mutation responsible for epilepsy can also alter channel response to antiepileptic drugs.     

Expression of the multidrug transporter P-glycoprotein in brain capillary endothelial cells and brain parenchyma of amygdala-kindled rats

Summary: Purpose: Based on data from brain biopsy samples of patients with pharmacoresistant partial epilepsy, overexpression of the multidrug transporter P‐glycoprotein (PGP) in brain capillary endothelium has recently been proposed as a potential mechanism of resistance to antiepileptic drugs (AEDs). We examined whether PGP is overexpressed in brain regions of amygdala‐kindled rats, a widely used model of temporal lobe epilepsy (TLE), which is often resistant to AEDs. Methods: Rats were kindled by stimulation of the basolateral amygdala (BLA); electrode‐implanted but nonkindled rats and naive (not implanted) rats served as controls. PGP was determined by immunohistochemistry either 1 or 2 weeks after the last kindled seizure, by using a monoclonal anti‐PGP antibody. Six brain regions were examined ipsi‐ and contralateral to the BLA electrode: the BLA, the hippocampal formation, the piriform cortex, the substantia nigra, the frontal and parietal cortex, and the cerebellum. Results: In both kindled rats and controls, PGP staining was observed mainly in microvessel endothelial cells and, to a much lesser extent, in parenchymal cells. The distribution of PGP expression across brain regions was not homogeneous, but significant differences were found in both the endothelial and parenchymal expression of this protein. In kindled rats, ipsilateral PGP expression tended to be higher than contralateral expression in several brain regions, which was statistically significant in the piriform cortex and parietal cortex. However, compared with controls, no significant overexpression of PGP in capillary endothelial cells or brain parenchyma of kindled rats was seen in any ipsilateral brain region, including the BLA. For comparison with kindled rats, kainate‐treated rats were used as positive controls. As reported previously, kainate‐induced seizures significantly increased PGP expression in the hippocampus and other limbic brain regions. Conclusions: Amygdala‐kindling does not induce any lasting overexpression of PGP in several brain regions previously involved in the kindling process. In view of the many pathophysiologic and pharmacologic similarities between the kindling model and TLE, these data may indicate that PGP overexpression in pharmacoresistant patients with TLE is a result of uncontrolled seizures but not of the processes underlying epilepsy. It remains to be determined whether transient PGP overexpression is present in kindled rats shortly after a seizure, and whether pharmacoresistant subgroups of kindled rats exhibit an increased expression of PGP. Furthermore, other multidrug transporters, such as multidrug resistance–associated protein, might be involved in the resistance of kindled rats to AEDs.     

Presence of a voltage-dependent anion channel 1 in the rat postsynaptic density fraction

Little is known about the molecular organization and functions of the postsynaptic density (PSD), a cytoskeletal specialization on the postsynaptic membrane. In an attempt to elucidate the protein composition of PSD, we have sequenced a 35 kDa protein of the rat forebrain PSD fraction. Amino acid sequence information of the tryptic peptides and immunoblot analyses revealed that the protein is a voltage-dependent anion channel 1 (VDAC1). VDAC1 was enriched in the PSD fraction and was partially soluble in 1% n-octyl glucoside (NOG) or Triton X-100. Our data indicate that VDAC1, which is originally found in the outer mitochondrial membrane, is also present in the central nervous system (CNS) synapses in association with the PSD 'core'.     

A comparison of extracellular levels of phenytoin in amygdala and hippocampus of kindled and non-kindled rats

Temporal lobe epilepsy is often refractory to antiepileptic drugs (AEDs). Accordingly, amygdala-kindled rats, a widely used model of temporal lobe epilepsy, have previously been found to be less responsive to AED treatment than non-kindled rats. In view of recent findings of over-expression of multidrug transporters in the blood-brain barrier of patients with pharmacoresistant epilepsy, one explanation for the finding of difficult-to-treat seizures in kindled rats would be a reduced penetration of AEDs into epileptogenic brain tissue. For evaluation of this possibility, we used brain microdialysis in order to compare extracellular levels of the AED phenytoin in amygdala and hippocampus of conscious, unrestrained amygdala-kindled and non-kindled rats. Consistent with the lower anticonvulsant efficacy of phenytoin in kindled rats, average phenytoin levels in dialysates of kindled rats were lower (up to 30%) than in non-kindled controls, but the differences were not statistically significant.This indicates that either the relatively large interindividual variation in dialysate levels of phenytoin masks functionally significant differences in individual kindled rats or that alterations in brain drug penetration are not involved in the lowered response of kindled rats to AEDs.     

Decreased expression of synaptic vesicle protein 2A, the binding site for levetiracetam, during epileptogenesis and chronic epilepsy

Purpose:   We previously showed that gene expression of synaptic vesicle protein 2A (SV2A), the binding site for the antiepileptic drug levetiracetam, is reduced during epileptogenesis in the rat. Since absence of SV2A has been associated with increased epileptogenicity, changes in expression of SV2A could have consequences for the progression of epilepsy. Therefore we investigated hippocampal SV2A protein expression of temporal lobe epilepsy (TLE) patients and in rats during epileptogenesis and in the chronic epileptic phase.
Methods:   SV2A immunocytochemistry and Western blot analysis were performed on the hippocampus of autopsy controls, patients that died from status epilepticus (SE), and pharmacoresistant TLE patients. In addition, in epileptic rats, SV2A expression was determined after SE during the acute, latent, and chronic epileptic phase.
Results:   In control tissue, presynaptic SV2A was expressed in all hippocampal subfields, with strongest expression in mossy fiber terminals. SV2A positive puncta were distributed in a patchy pattern over the somata and dendrites of neurons. SV2A decreased throughout the hippocampus of TLE patients with hippocampal sclerosis (HS), compared to autopsy control, SE, and non-HS tissue. In most rats, SV2A was already decreased in the latent period especially in the inner molecular layer and stratum lucidum. Similarly as in humans, SV2A was also decreased throughout the hippocampus of chronic epileptic rats, specifically in rats with a progressive form of epilepsy.
Discussion:   These data support previous findings that reduced expression of SV2A could contribute to the increased epileptogenicity. Whether this affects the effectiveness of levetiracetam needs to be further investigated.     

Central therapeutic effects of peripheral vagus nerve stimulation

Despite the recent addition of more than ten new antiepileptic drugs on the market, epilepsy remains poorly controlled in almost 30% of patients. For this subgroup of patients with pharmacoresistant epilepsy, vagus nerve stimulation (VNS) has become a viable option. More recently, it has also shown promise in treatment-resistant depression. This article discusses VNS's history, current applications, and potential to treat chronic neurologic and psychiatric disorders.     

The interface of preclinical evaluation with clinical testing of antiepileptic drugs: role of pharmacogenomics and pharmacogenetics

Despite the release of eight antiepileptic drugs (AEDs) during the last decade, the incidence of pharmacoresistant epilepsy has changed relatively little. Predicting efficacy and safety of AEDs in people with epilepsy from acute seizure models in rodents is difficult and risky. It is becoming increasingly clear that genetic polymorphisms play an integral role in variability in both antiepileptic drug pharmacokinetics and pharmacodynamics. The publication of the human genome and increasing sophisticated and powerful genetic tools offers new methods for screening drugs and predicting deadly idiosyncratic side effects. In this review the use of pharmacogenomic and pharmacokinetic techniques in the development and monitoring of antiepileptic drug therapy is reviewed. Genetic techniques have the potential of identifying novel drug targets, predicting drug response, and identifying individuals at risk for serious idosyncratic reactions.     

Predictors of outcome after temporal lobectomy for the treatment of intractable epilepsy

To assess short- and long-term seizure freedom, the authors reviewed 371 patients who underwent anterior temporal lobectomy to treat pharmacoresistant epilepsy. The mean follow-up duration was 5.5 years (range 1 to 14.1 years). Fifty-three percent of patients were seizure free at 10 years. The authors identified multiple predictors of recurrence. Results of EEG performed 6 months postoperatively correlated with occurrence and severity of seizure recurrence, in addition to breakthrough seizures with discontinuation of antiepileptic drugs.     

Pregabalin effect on steady-state pharmacokinetics of carbamazepine, lamotrigine, phenobarbital, phenytoin, topiramate, valproate, and tiagabine

By reducing neuronal excitability through selective binding to the α(2)δ subunit of voltage-dependent calcium channels, pregabalin effectively treats epilepsy, chronic pain, and anxiety disorders. To evaluate if pregabalin coadministration affects pharmacokinetics of other antiepileptic drugs, population pharmacokinetic analyses using NONMEM software were performed on data from three epilepsy trials involving seven antiepileptic drugs with pregabalin as add-on therapy. Results demonstrated that pregabalin did not alter the steady-state plasma concentrations of carbamazepine, lamotrigine, phenobarbital, phenytoin, tiagabine, topiramate, and valproate. Furthermore, the small percent change in the population estimate of antiepileptic drug plasma clearance values (-2% to +7%) suggests that pregabalin coadministration exerted no significant effect on the pharmacokinetics of these antiepileptic drugs, with the possible exception of tiagabine (+34.9%). These findings are in agreement with those of previously published reports. A further clarification study is necessary for tiagabine. In conclusion, it appears that pregabalin can be coadministered with other antiepileptic drugs without concern for significantly altering their pharmacokinetic profiles.     

The pharmacokinetics of antiepileptic drugs in rats: consequences for maintaining effective drug levels during prolonged drug administration in rat models of epilepsy

Rodent models of chronic epilepsy with spontaneous recurrent seizures likely represent the closest parallel to the human condition. Such models may be best suited for therapy discovery for pharmacoresistant epilepsy and for antiepileptogenic or disease-modifying therapeutics. However, the use of such rodent models for therapy discovery creates problems with regard to maintaining effective drug levels throughout a prolonged testing period. This is particularly due to the fact that rodents such as rats and mice eliminate most drugs much more rapidly than humans. Thus, knowledge about elimination rate of a test drug in a laboratory species is essential for development of a treatment paradigm that allows maintaining adequate drug levels in the system over the period of treatment. Currently, the most popular models of epilepsy with spontaneous seizures are poststatus epilepticus models of temporal lobe epilepsy in rats. Such models are both used for studies on antiepileptogenesis and drug resistance. For validation of these models, current antiepileptic drugs (AEDs) have to be used. In this article, the elimination rates of these AEDs and their effective plasma levels in rats are reviewed as a guide for developing treatment protocols for chronic drug testing. The advantages and disadvantages of several technologies for drug delivery are discussed, and some examples for calculation of adequate treatment protocols are given. As shown in this review, because of the rapid elimination of most AEDs in rats, it is no trivial task to maintain effective steady-state AED levels in the plasma throughout the day over multiple days to ensure that there will be adequate levels in the system for the purpose of the experiment. However, the use of an adequate dosing regimen that is based on elimination rate is an absolute prerequisite when using rat models for discovery of new antiepileptogenic therapies or therapies for pharmacoresistant epilepsy, because otherwise such models may lead to erroneous conclusions about drug efficacy.     

局灶性皮质发育障碍致痫的蛋白质组学研究

目的 寻找皮质发育障碍致痫的疾病相关差异蛋白,以期寻找抗癫痫治疗的新靶点,同时寻找早期十预脑皮质发育障碍新的手段.方法 利用液氮损伤诱导皮质发育障碍,应用比较蛋白质组学方法研究致痫组和对照组皮质蛋白表达图谱差异,并对发现的差异蛋白质进行分析和鉴定.结果皮质发育障碍致痫组筛选到103个差异表达蛋白质斑点,其中64个在致痫组表达上调,39个在致痈组表达下调.有12个蛋白质最终鉴定确认,分别是lissencephaly-lprotein (LIS-1)、synaptotagmin Ⅳ、胶质纤维酸性蛋白(GFAP)、热休克蛋白70(HSP70)、生长相关蛋白-43(GAP-43)、neuronal enolase、tubulin beta chain、谷氨酰胺合成酶、神经元胞浆蛋白、电压依赖性阴离子通道1(VDAC1)、丙酮酸激酶(PK)、neurofilament light polypeptide.结论 12个差异蛋白鉴定有利于进一步研究皮质发育障碍与癫痫关系,该结果也为运用蛋白质组学方法寻找皮质发育障碍致痫治疗新靶点提供了实验数据.     

Effects of antiepileptic drug therapy on heart rate variability in children with epilepsy

Impaired cardiac autonomic function may contribute to the risk of sudden unexpected death in epilepsy. Heart rate variability (HRV) is a useful tool for the detection of sympathetic-parasympathetic balance of autonomic nervous system. In the present study, epilepsy patients who had never received antiepileptic medication and those whose seizures have been successfully controlled with antiepileptic drugs were compared with each other and a control group in order to investigate the effects of epilepsy and various antiepileptic drugs on HRV. HRV were tested via 5 min ECG monitoring in 92 patients and 83 controls. Time domain parameters including SDNN, RMSSD and the frequency domain parameters including HF (reflects parasympathetic activity) and LF (reflects sympathetic activity) were assessed. In this group, 78 patients were using antiepileptic drugs including valproic acid (n=33), oxcarbazepine (n=19), phenobarbital (n=11), combined regimens (n=10) and other drugs (n=5), while 14 patients had never received antiepileptic medication. For both of the epilepsy patients groups with or without treatment, time domain parameters were found to be significantly suppressed. In addition, parasympathetic activity was found to be decreased (HF was decreased, LF/HF ratio was increased) in epilepsy patients without antiepileptic drug therapy. Our results indicate that seizure control with antiepileptic drugs may help to improve the cardiac autonomic function impairment in epilepsy patients.     

Inhibition of multidrug transporters by verapamil or probenecid does not alter blood-brain barrier penetration of levetiracetam in rats

Overexpression of multidrug efflux transporters such as P-glycoprotein (Pgp; ABCB1) or multidrug resistance proteins (MRPs; ABCC) in the blood-brain barrier has recently been suggested to explain, at least in part, pharmacoresistance in epilepsy, which affects about 30% of all patients with this common brain disorder. The novel antiepileptic drug (AED) levetiracetam (LEV) is an effective and well tolerated drug in many patients with otherwise AED-refractory epilepsy. One explanation for the favorable efficacy of LEV in pharmacoresistant patients would be that LEV is not a substrate for Pgp or MRPs in the BBB. In the present study, we used in vivo microdialysis in rats to study whether the concentration of LEV in the extracellular fluid of the cerebral cortex can be modulated by inhibition of Pgp or MRPs, using the Pgp inhibitor verapamil and the MRP1/2 inhibitor probenecid. Local perfusion with verapamil or probenecid via the microdialysis probe did not increase the extracellular brain concentration of LEV, which is in contrast to various other AEDs which have been studied previously by the same experimental protocol in this model. The data indicate that brain uptake of LEV is not affected by Pgp or MRP1/2 which may be an important reason for its antiepileptic efficacy in patients whose seizures are poorly controlled by other AEDs.     

Stiripentol

Stiripentol (STP) is a new antiepileptic compound made by Biocodex. It recently proved to increase the GABAergic transmissionin vitro in an experimental model of immature rat. Clinical studies were based on the fact that STP also acts as an inhibitor of CYP3A4, CYP1A2, and CYP2C19in vivo in epileptic patients. Whereas the studies in adult patients were disappointing, the trials conducted in pediatric populations demonstrated a specific efficacy of STP in severe myoclonic epilepsy in infancy, Dravet syndrome, when combined with valproate and clobazam. Based on these results, STP was granted orphan drug status in the European Union for the treatment of Dravet syndrome. The French experience in compassionate use suggests that STP might also be of benefit when combined with carbamazepine in pediatric patients with pharmacoresistant partial epilepsy. The interactions of STP with a large number of drugs need to be carefully taken into account, with doses of the combined antiepileptic drugs adjusted to improve the tolerability of the therapeutic association.     

A kindling model of pharmacoresistant temporal lobe epilepsy in Sprague-Dawley rats induced by Coriaria lactone and its possible mechanism

PURPOSE: The aim of this study was to develop a new animal model of pharmacoresistant temporal lobe epilepsy (TLE) by repeated intramuscular injection of Coriaria lactone (CL) at subthreshold dosages and to explore the mechanisms that might be involved. METHODS: Healthy male Sprague-Dawley rats (n = 160) were randomized into four groups during the kindling process: three groups (n = 50 for each group) received CL injection at subthreshold dosages (1.25, 1.5, and 1.75 mg/kg, respectively), and ten received normal saline (NS) injection as a control group. The maximal human adult dosage of carbamazepine (CBZ), valproate (VPA), and phenytoin (PHT) was administered as monotherapy to different groups of kindled rats for 1 month (n = 20 for each group). Changes in EEG recording, seizure number, intensity (expressed as grade 1-5 according to Racine stage), and duration, including spontaneous seizures during different interventions, were compared. The expression of P-170, a multiple drug resistance gene (MDR1) encoding P-glycoprotein, was measured in brain samples from different groups of experimental rats by using an image analysis and measurement system (ImagePro-Plus 4.0). RESULTS: A total of 70 (46.7%) rats were fully kindled with a median of 15 (seven to 20) CL injections. Electrocorticogram (ECoG) including hippocampal (EHG) monitoring revealed the temporal lobe origins of epileptiform potentials, which were consistent with the behavioral changes observed. Spontaneous seizures occurred with frequency and diurnal patterns similar to those of human TLE. The antiepileptic drugs (AEDs) tested lacked a satisfactory seizure control. The maximal P-170 expression was in the kindled rats with AED treatment; the next highest was in the kindled rats without AED intervention. Nonkindled SD rats with CL injection also had increased P-170 expression compared with control SD rats. CONCLUSIONS: The study provided a simple and stable animal TLE kindling model with pharmacoresistant properties. The pharmacoresistance observed in the kindled rats to CBZ, VPA, and PHT at maximal human adult dosages together with the increased P-170 expression was a distinct feature of this model. This model might be used in further investigations of the mechanisms involved in pharmacoresistant TLE and for developing new AEDs.