Effects of fluoxetine and TFMPP on spontaneous seizures in rats with pilocarpine-induced epilepsy

PURPOSE: Fluoxetine is a selective serotonin [5-hydroxytryptamine (5-HT)] reuptake inhibitor (SSRI) commonly used to treat depression. Some uncontrolled clinical studies have reported that SSRIs increase seizures, but animal experiments with evoked-seizure models have suggested that SSRIs at therapeutic doses decrease seizure susceptibility. We tested the hypothesis that fluoxetine and trifluoromethylphenylpiperazine (TFMPP, a nonselective 5-HT-receptor agonist) reduce the frequency of spontaneous motor seizures in pilocarpine-treated rats. METHODS: Fluoxetine (20 mg/kg) and TFMPP (5 mg/kg) were administered to rats with pilocarpine-induced epilepsy. Phenobarbital (PB; 10 mg/kg) was a positive control, and saline (i.e., 0.5 ml) controlled for the injection protocol. Each rat received each treatment (intraperitoneally) once per day for 5 consecutive days with 1 week between treatments. Rats were continuously video-monitored for the last 72 h of each treatment. RESULTS: When compared with saline over the entire 72-h observation period, PB and fluoxetine treatment, but not TFMPP, reduced the spontaneous-seizure rate. Plots of magnitude of the drug effect as a function of seizure frequency after saline treatment revealed larger drug effects for fluoxetine and PB in the rats with the highest control seizure rate. When the data from the five rats with the highest seizure frequency in saline were analyzed for the first 6 h after treatment, TFMPP also significantly reduced seizure frequency. CONCLUSIONS: Animal models with spontaneous seizures can be used to screen potential antiepileptic drugs, and fluoxetine and TFMPP reduce spontaneous seizures in the pilocarpine model of temporal lobe epilepsy.     

The antidepressants citalopram and reboxetine reduce seizure frequency in rats with chronic epilepsy

Purpose: For a long time, antidepressants have been thought to possess proconvulsant properties. This assumption, however, remains controversial, since anticonvulsant effects have been attributed to certain antidepressants. To date, it remains unclear which antidepressants can be used for the treatment of depression in patients with epilepsy. In this respect, studies investigating the convulsant liability of antidepressants in a chronic epilepsy model can give valuable information. The present study was designed to determine the seizure liability of citalopram and reboxetine in the kainic acid–induced post–status epilepticus model for temporal lobe epilepsy. Methods: Two months after the induction of status epilepticus, chronic epileptic rats (n = 16) were video‐electroencephalography (EEG) monitored during seven consecutive weeks. Weeks 1, 3, 5, and 7 served as sham weeks during which the rats received intraperitoneal saline injections for four consecutive days, followed by a 3‐day sham washout period during which no injections were given. During weeks 2, 4, and 6, rats received intraperitoneal injections with either citalopram (5, 10, and 15 mg/kg, once daily, n = 8) or reboxetine (10, 20, and 30 mg/kg, twice daily, n = 8) for 4 days, again followed by a washout period of 3 days. Drugs were administered in a randomly assigned fixed‐dose regimen per week. Each rat served as its own control. The drug doses were selected based on the doses reported to have antidepressant effects in rats. Key Findings: Citalopram significantly decreased the spontaneous seizure frequency at the highest dose tested, that is, the mean number of seizures decreased from 12.8 seizures to 8.8 seizures per week (31%) after treatment with 15 mg/kg citalopram. This dose also significantly decreased the cumulative seizure duration. Administration of 5 and 10 mg/kg citalopram did not alter the seizure frequency. The two highest doses of reboxetine significantly decreased the spontaneous seizure frequency, that is, 20 mg/kg reboxetine decreased the seizure frequency from 14.1 to 7.9 (44%) and 30 mg/kg reboxetine decreased the seizure frequency from 11.8 to 7.2 (39%). In addition, both doses significantly decreased the cumulative seizure duration. Administration of 10 mg/kg reboxetine did not alter seizure frequency. Citalopram and reboxetine had no effect on seizure severity and seizure duration in any of the doses tested. Significance: In general we can conclude that antidepressant doses of citalopram and reboxetine have, depending on the dose, an anticonvulsant effect or no effect on spontaneous seizures in the kainic acid–induced post–status epilepticus rat model.     

Anticonvulsant effects of carbamazepine on spontaneous seizures in rats with kainate-induced epilepsy: comparison of intraperitoneal injections with drug-in-food protocols

PURPOSE: The present study evaluated the effectiveness of intraperitoneal (IP) injections and oral administration of carbamazepine (CBZ) in food on the frequency of spontaneous motor seizures in rats with kainate-induced epilepsy. The purpose was to develop a convenient drug-in-food approach for continuous, long-term administration of potential antiepileptic drugs (AEDs). METHODS: Single IP injections of CBZ (10-100 mg/kg) were compared to vehicle injections via six AED-versus-vehicle tests using a repeated-measures, crossover protocol. Similar protocols were used with CBZ-containing or control food pellets. RESULTS: CBZ significantly reduced motor seizure frequency at 30 and 100 mg/kg after single IP injections, and these doses completely blocked motor seizures during a 6-h postdrug epoch in 25% and 70% of the animals, respectively. Single administrations of 30 mg/kg and 100 mg/kg CBZ in food also significantly reduced motor seizures, and blocked seizures in 33% and 89% of the rats, respectively. CBZ administered in food three times per day (100 mg/kg x3 CBZ in food) continuously blocked nearly all motor seizures over a 5-day period, and completely suppressed motor seizures in 50% of the animals tested. CONCLUSIONS: CBZ strongly suppresses spontaneous motor seizures, and single doses of CBZ in food are as effective as IP injections in rats with kainate-induced epilepsy. CBZ administered regularly in food continuously blocks nearly all motor seizures, and may provide a relatively simple method to test AEDs in chronic models of epilepsy.     

Clinical value and predictors of subclinical seizures in patients with temporal lobe epilepsy undergoing scalp video-EEG monitoring

The aim of this study was to determine the clinical importance and predictors of SCSs in a large population of patients with temporal epilepsy (TLE) undergoing video electroencephalographic (VEEG) monitoring. We reviewed the VEEG data of 327 consecutive patients with TLE admitted to our epilepsy center between August 2012 and January 2017. Demographic, electro-clinical, and neuroimaging data were recorded and re-analyzed. To our knowledge, this is the first study assessing SCSs recorded by long-term VEEG monitoring in patients with TLE. Twenty-seven of 327 (8.3%) patients exhibited SCSs during VEEG monitoring. Of these patients, 24 had both SCSs and clinical seizures. The mean duration of the SCSs was 23.18 s (range: 5–1307 s). Of the 27 patients with SCSs, 24 (88.9%) showed localizing value during the diagnostic process. Seventeen patients exhibited colocalization with clinical seizures, 4 showed useless localization related to clinical seizures, and 3 did not have clinical seizures. Sixteen patients (59.3%) experienced their first SCSs within the first 24 h of monitoring and one had the first SCSs within 20 min. Multivariate logistic regression analysis showed that age <18 years at VEEG monitoring (OR = 3.272, 95% CI = 1.283–8.343, p = 0.013) and bilateral IEDs (OR = 4.558, 95% CI = 1.982–10.477, p < 0.001) were independently associated with the presence of SCSs. Thus, SCSs are not uncommon in patients with TLE, particularly those with age <18 years or bilateral IEDs, and should be considered of significant clinical relevance during the diagnostic process.     

海人酸诱导颞叶癫癎大鼠海马中GAP-43和NCAM的表达变化以及托吡酯的干预作用

目的研究海人酸（KA）对大鼠海马中生长相关蛋白-43（GAP-43）和神经细胞粘附分子（NCAM）表达的影响，以及托吡酯（TPM）对其的干预作用。方法将48只大鼠随机分成生理盐水（NS）组、4mgKA组、10mgKA组和10mgKA＋TPM组（n=12），建立KA诱导颞叶癫癎大鼠模型和TPM干预模型，观察大鼠行为学改变，并通过RT-PCR和WesternBlot的方法测定各组大鼠海马中GAP-43及NCAM的mRNA和蛋白表达水平。结果大鼠建模成功；4mgKA组、10mgKA组大鼠GAP-43及NCAM的mRNA和蛋白表达水平明显高于NS组（P〈0．01），且10mgKA组高于4nagKA组（P〈0．01）；10mgKA＋TPM组大鼠的GAP-43和NCAM表达明显低于10mgKA组（P〈0．01）。结论KA能够诱导致癎大鼠海马GAP-43和NCAM表达上调，且与KA剂量有关，而TPM能够抑制KA诱导的GAP-43和NCAM的表达上调。     

大鼠颞叶癫痫模型的建立及评价

目的 探讨海马局部给药建立颞叶癫痫模型方法及其行为、形态学、脑电和影像学改变。方法 通过立体定向术向大鼠海马局部注射海人酸fKA）建立颞叶癫痫模型。观察其行为学、形态学、脑电和影像学改变情况。结果 KA注入海马后模型大鼠麻醉清醒后有典型癫痫发作表现：凝视、湿狗样抖动、口的咀嚼运动、点头、肢体阵挛等，随后表现为阵发性旋转，并身体立起、向上窜跳、跌倒、四肢抽搐，约8h后发作停止，逐渐恢复到正常大鼠状态。以后每周发作1-2次，主要为Ⅳ～Ⅴ级。同时有额叶皮层和海马的癫痫放电脑电图及病理、影像学表现。结论 大鼠脑内局部注入KA后癫痫发作明显，其行为表现、海马病理改变、脑电及影像改变类似人类颞叶癫痫．可作为较好的研究颞叶癫痫的工具。     

Kainic acid-induced dorsal and ventral hippocampal seizures in rats

Despite reports of differing regional seizure susceptibility in the hippocampus, hippocampal initiation of limbic seizures has not been precisely localized. We compared seizures induced by kainic acid microinjection into the left dorsal and ventral hippocampus of rats. Discharges following ventral injections rapidly propagated to the left amygdala and sensorimotor cortex unlike seizures following dorsal injections. The ventral group showed various ictal behaviors including motor manifestations, while dorsally injected rats showed only immobilization.     

Intrahippocampal infusion of botulinum neurotoxin E (BoNT/E) reduces spontaneous recurrent seizures in a mouse model of mesial temporal lobe epilepsy

Mesial temporal lobe epilepsy (MTLE) is one of the most common forms of human epilepsy, and it is often resistant to conventional antiepileptic drug (AED) therapy. Here we tested whether a single intrahippocampal administration of the synaptic blocker botulinum neurotoxin E (BoNT/E) is effective in reducing spontaneous recurrent seizures (SRS) in a mouse model of MTLE. Unilateral intrahippocampal injection of kainic acid (KA) in mice was used as a model of MTLE. Electroencephalography (EEG) recordings of SRS were performed during the chronic phase of epilepsy, before and after administration of either BoNT/E or vehicle. Frequency of SRS was significantly decreased for at least 5 days following BoNT/E, but not vehicle, infusion. Our findings demonstrate that BoNT/E can effectively reduce seizure incidence in a mouse model of MTLE.     

Temporal lobe epilepsy in children: etiology in a cohort with new-onset seizures

PURPOSE: The aim of this study was to characterize the incidence and etiology of temporal lobe epilepsy (TLE) in a community-based cohort of children with new-onset disease. METHODS: A community-based cohort of 30 children with TLE was studied. The patients had new-onset disease before age 14 years between 1995 and 1999. They underwent clinical, EEG, and magnetic resonance imaging investigations. RESULTS: The patients could be divided in three main groups according to likely etiology, as suggested by Harvey et al. (Neurology 1997;49:960-8). Group 1 consisted of eight (26.7%) children with malformations or long-standing, nonprogressive tumors (developmental TLE). Arachnoid cysts were found in three, dual pathology [cortical dysplasia and hippocampal sclerosis (HS)] in one, and focal cortical dysplasia with glioproliferative changes in one patient. Dysembryoplastic neuroepithelial tumor was responsible for the epilepsy in one, and ganglioglioma, in two children. Group 2 consisted of seven (23.3%) children with a significant antecedent and/or HS. Five children had a significant illness or event before the onset of TLE, including perinatal hypoxic-ischemic encephalopathy in one, encephalitis in one, traumatic brain injury in two, and complex febrile seizures in one. HS was found in the patients with traumatic brain injury and complex febrile seizures in the history in addition to two children without known antecedents. Group 3 comprised 15 (50%) children with no abnormality on neuroimaging and no significant antecedents (cryptogenic TLE). CONCLUSIONS: Etiologic differences between children with new-onset TLE may have prognostic implications: children with TLE and significant antecedents/HS are expected to have the greatest risk of continued seizures and psychological problems.     

Bumetanide reduces seizure frequency in patients with temporal lobe epilepsy

Alterations in the balance of K‐Na‐2Cl cotransporter (NKCC1) and Na‐Cl cotransporter (KCC2) activity may cause depolarizing effect of γ‐aminobutyric Acid (GABA), and contribute to epileptogenesis in human temporal lobe epilepsy. NKCC1 facilitates accumulation of chloride inside neurons and favors depolarizing responses to GABA. In the current pilot study we provide the first documented look at efficacy of bumetanide, a specific NKCC1 antagonist, on reduction of seizure frequency in adult patients with temporal lobe epilepsy. According to our results, seizure frequency was reduced considerably in these patients. Furthermore, epileptiform discharges decreased in two of our patients. If the efficacy of bumetanide is proven in large scale studies, it can be used as a supplemental therapy in temporal lobe epilepsy.     

恒河猴颞叶癫痫模型的建立

目的 应用立体定向方法单侧海马内注射海人酸,建立恒河猴颞叶癫痫模型,并评价其生物学特性.方法 通过立体定向手术,恒河猴右侧海马注射海人酸,观察恒河猴行为学、神经电生理、影像学、组织病理及超微结构改变.结果 海人酸注射后恒河猴出现典型的颞叶癫痫发作表现,脑电图表现为棘波、慢波、棘慢波、尖波发放.MRI、MRS可见海马硬化的表现,组织学标本显示颞角扩大、海马硬化,HE染色可见神经元缺失、胶质细胞增生、瘢痕萎缩,电镜显示神经元固缩、血脑屏障破坏、星形细胞肿胀、细胞器受损.结论 立体定向单侧注入海人酸后恒河猴癫痫发作明显,其行为学、神经电生理、影像学、神经病理改变符合颞叶内侧型癫痫表现,可作为癫痫模型.     

Hippocampal and Entorhinal Cortex High-Frequency Oscillations (100–500 Hz) in Human Epileptic Brain and in Kainic Acid-Treated Rats with Chronic Seizures

Summary: Purpose: Properties of oscillations with frequencies >100 Hz were studied in kainic acid (KA)-treated rats and compared with those recorded in normal and kindled rats as well as in patients with epilepsy to determine differences associated with epilepsy. Methods: Prolonged in vivo wideband recordings of electrical activity were made in hippocampus and entorhinal cortex (EC) of (a) normal rats, (b) kindled rats, (c) rats having chronic recurrent spontaneous seizures after intrahippocampal KA injections, and (d) patients with epilepsy undergoing depth electrode evaluation in preparation for surgical treatment. Results: Intermittent oscillatory activity ranging from 100 to 200 Hz in frequency and 50–150 ms in duration was recorded in CA1 and EC of all three animal groups, and in epileptic human hippocampus and EC. This activity had the same characteristics in all groups, resembled previously observed “ripples” described by Buzsáki et al., and appeared to represent field potentials of inhibitory postsynaptic potentials (IPSPs) on principal cells. Unexpectedly, higher frequency intermittent oscillatory activity ranging from 200 to 500 Hz and 10–100 ms in duration was encountered only in KA-treated rats and patients with epilepsy. These oscillations, termed fast ripples (FRs), were found only adjacent to the epileptogenic lesion in hippocampus, EC, and dentate gyrus, and appeared to represent field potential population spikes. Their local origin was indicated by correspondence with the negative phase of burst discharges of putative pyramidal cells. Conclusions: The persistence of normal-appearing ripples in epileptic brain support the view that inhibitory processes are preserved. FRs appear to be field potentials reflecting hypersynchronous bursting of excitatory neurons and provide an opportunity to study the role of this pathophysiologic phenomenon in epilepsy and seizure initiation. Furthermore, if FR activity is unique to brain areas capable of generating spontaneous seizures, its identification could be a powerful functional indicator of the epileptic region in patients evaluated for surgical treatment.     

Somatosensory auras in refractory temporal lobe epilepsy

PURPOSE: To determine the prevalence, manifestations, lateralizing value, and surgical prognostic value of somatosensory auras (SSAs) in patients with refractory temporal lobe epilepsy (TLE). METHODS: Eighty-one consecutive patients undergoing temporal lobectomy for refractory complex-partial seizures were screened for SSAs. The characteristics of the somatosensory phenomena, occurrence of other aura types, seizure semiology, findings of EEG and imaging studies, temporal lobe neuropathology, and postoperative seizure outcome were determined in each patient with SSAs. RESULTS: Nine (11%) of 81 patients with refractory temporal lobe seizures reported distinct SSAs as part of their habitual seizures. The most common manifestation of SSAs was tingling (eight of nine, 89%), but sensory loss (one of nine, 11%) and pain (one of nine, 11%) also were reported. Five patients had unilateral somatosensory symptoms, and four patients had bilateral somatosensory symptoms. Seizure origin was in the contralateral temporal lobe in four (80%) of five patients with unilateral SSAs, including all patients with unilateral SSAs affecting a limb. Partial temporal lobe resection produced complete seizure remission in all nine (100%) patients 1 year after surgery and in seven (78%) of nine patients 2 years after surgery. CONCLUSIONS: SSAs occur more frequently than previously appreciated in patients with refractory temporal lobe seizures and usually manifest as either unilateral or bilateral tingling. In patients with temporal lobe seizures, unilateral SSAs involving a limb suggest a seizure origin in the contralateral temporal lobe. The surgical outcome of TLE patients with SSAs is favorable. Thus the presence of SSAs should not serve as a deterrent to temporal lobe resection in patients with clearly defined TLE.     

Hypersalivation in temporal lobe epilepsy

PURPOSE: We sought to determine whether hypersalivation helps lateralize seizure onset during complex partial seizures of temporal lobe origin. Several clinical signs, which help lateralize seizure onset, have been reported in temporal lobe epilepsy (TLE). Increased salivation only occasionally has been reported as a manifestation of partial epilepsy. METHODS: Of 590 consecutive patients admitted for video-EEG monitoring, either as a part of a presurgical evaluation of medically intractable epilepsy or for diagnosis and clarification of their paroxysmal symptoms, we identified 10 patients with ictal hypersalivation as a prominent manifestation of complex partial seizures. We reviewed the clinical features, scalp-sphenoidal video-EEG monitoring, intracarotid amytal (Wada) testing, hippocampal volumetric magnetic resonance imaging (MRI), and fluorodeoxyglucose-positron emission tomography (FDG-PET) scans of these patients. RESULTS: Of the 10 patients with ictal hypersalivation, seven patients had nondominant/right TLE, and three patients had dominant/left TLE. All patients had hippocampal atrophy on volumetric MRI. Eight of the 10 patients underwent standard temporal lobectomy with amygdalohippocampectomy (six right, two left). All of the operated-on patients had a seizure-free (Engel class I) outcome, and their increased salivation resolved. Two patients, who did not undergo surgical treatment, continue to have complex partial seizures with increased salivation. CONCLUSIONS: We conclude that increased salivation as a prominent ictal finding in complex partial seizures of temporal lobe origin is more likely to be of nondominant temporal lobe origin. Further studies with larger numbers of patients are needed to replicate this finding.     

Continuous local intrahippocampal delivery of adenosine reduces seizure frequency in rats with spontaneous seizures

Purpose: Despite different treatment options for patients with refractory epilepsy such as epilepsy surgery and neurostimulation, many patients still have seizures and/or drug‐related cerebral and systemic side effects. Local intracerebral delivery of antiepileptic compounds may represent a novel strategy with specific advantages such as the option of higher local doses and reduced side effects. In this study we evaluate the antiepileptic effect of local delivery of adenosine in the kainic acid rat model, a validated model for temporal lobe epilepsy. Methods: Fifteen rats, in which intraperitoneal kainic acid injection had induced spontaneous seizures, were implanted with a combination of depth electrodes and a cannula in both hippocampi. Cannulas were connected to osmotic minipumps to allow continuous hippocampal delivery. Rats were freely moving and permanently monitored by video‐EEG (electroencephalography). Seizures were scored during 2 weeks of local hippocampal delivery of saline (baseline), followed by 2 weeks of local adenosine (6 mg/ml) (n = 10) or saline (n = 5) delivery (0.23 μl/h) (treatment). In 7 of 10 adenosine‐treated rats, saline was also delivered during a washout period. Results: During the treatment period a mean daily seizure frequency reduction of 33% compared to the baseline rate was found in adenosine‐treated rats (p < 0.01). Four rats had a seizure frequency reduction of at least 50%. Both nonconvulsive and convulsive seizures significantly decreased during the treatment period. In the saline‐control group, mean daily seizure frequency increased with 35% during the treatment period. Conclusions: This study demonstrates the antiseizure effect of continuous adenosine delivery in the hippocampi in rats with spontaneous seizures.     

难治性颞叶癫痫术后急性发作对远期预后的预测价值

目的探讨药物难治性颞叶癫痫术后急性发作对远期预后的影响。方法回顾性分析我院自2009年6月-2010年6月收治的52例药物难治性颞叶癫痫患者的临床资料,所有患者均接受外科治疗,术后定期门诊或电话随访。根据术后7天患者有无急性发作,分为2组,分为实验组(复发),对照组(未复发)。将2组患者随访资料、远期预后(5年)等进行对比分析。结果实验组癫痫控制满意率为35.0%,对照组控制满意率为68.8%,实验组明显低于对照组,差异有统计学意义(χ2=5.683,P=0.017)。在多元Logistic回归分析结果中,复发次数、术前使用抗癫痫药物数量、术后脑电图,术后急性发作与术前习惯性发作相似是影响远期预后的独立影响因子。结论难治性颞叶癫痫术后急性发作对患者远期预后存在影响,已明确的影响因子包括:复发次数、术前抗癫痫药≥3种,术后脑电图及术后急性发作与术前习惯性发作相似。