Altered Hippocampal Activation in Seizure-Prone CACNA2D2 Knock-out Mice.

The voltage-gated calcium channel subunit α2δ-2 controls calcium-dependent signaling in neurons, and loss of this subunit causes epilepsy in both mice and humans. To determine whether mice without α2δ-2 demonstrate hippocampal activation or histopathological changes associated with seizure activity, we measured expression of the activity-dependent gene c-fos and various histopathological correlates of temporal lobe epilepsy (TLE) in hippocampal tissue from wild-type (WT) and α2δ-2 knock-out (CACNA2D2 KO) mice using immunohistochemical staining and confocal microscopy. Both genotypes demonstrated similarly sparse c-fos and ΔFosB expressions within the hippocampal dentate granule cell layer (GCL) at baseline, consistent with no difference in basal activity of granule cells between genotypes. Surprisingly, when mice were assayed 1 h after handling-associated convulsions, KO mice had fewer c-fos-positive cells but dramatically increased ΔFosB expression in the dentate gyrus compared with WT mice. After administration of a subthreshold pentylenetetrazol dose, however, KO mice dentate had significantly more c-fos expression compared with WT mice. Other histopathological markers of TLE in these mice, including markers of neurogenesis, glial activation, and mossy fiber sprouting, were similar between WT and KO mice, apart from a small but statistically significant increase in hilar mossy cell density, opposite to what is typically found in mice with TLE. This suggests that the differences in seizure-associated dentate gyrus function in the absence of α2δ-2 protein are likely due to altered functional properties of the network without associated structural changes in the hippocampus at the typical age of seizure onset.

Novel predictive approaches for drug-induced convulsions in non-human primates using machine learning and heart rate variability analysis.

Drug-induced convulsions are a major challenge to drug development because of the lack of reliable biomarkers. Using machine learning, our previous research indicated the potential use of an index derived from heart rate variability (HRV) analysis in non-human primates as a biomarker for convulsions induced by GABAA receptor antagonists. The present study aimed to explore the application of this methodology to other convulsants and evaluate its specificity by testing non-convulsants that affect the autonomic nervous system. Telemetry-implanted males were administered various convulsants (4-aminopyridine, bupropion, kainic acid, and ranolazine) at different doses. Electrocardiogram data gathered during the pre-dose period were employed as training data, and the convulsive potential was evaluated using HRV and multivariate statistical process control. Our findings show that the Q-statistic-derived convulsive index for 4-aminopyridine increased at doses lower than that of the convulsive dose. Increases were also observed for kainic acid and ranolazine at convulsive doses, whereas bupropion did not change the index up to the highest dose (1/3 of the convulsive dose). When the same analysis was applied to non-convulsants (atropine, atenolol, and clonidine), an increase in the index was noted. Thus, the index elevation appeared to correlate with or even predict alterations in autonomic nerve activity indices, implying that this method might be regarded as a sensitive index to fluctuations within the autonomic nervous system. Despite potential false positives, this methodology offers valuable insights into predicting drug-induced convulsions when the pharmacological profile is used to carefully choose a compound.

Creatine attenuates seizure severity, anxiety and depressive-like behaviors in pentylenetetrazole kindled mice.

Epilepsy has been associated with several behavioral changes such as depression and anxiety while some antiepileptic drugs can precipitate psychiatric conditions in patients. This study evaluated the ameliorative effect of creatine on seizure severity and behavioral changes in pentylenetetrazole (PTZ) kindled mice. Mice were kindled by administering sub-convulsive doses of PTZ (35 mg/kg i.p.) at interval of 48 h. The naïve group (n = 7) constituted group 1, while successfully kindled mice were randomly assigned to five groups (n = 7). Group II served as vehicle treated group; groups III-V were treated with creatine 75, 150, and 300 mg/kg/day, p.o; Group V was given 25 mg/kg/day of phenytoin p.o. The treatment was for 15 consecutive days. The intensity of convulsion was scored according to a seven-point scale ranging from stage 0-7. Tail suspension test (TST) and Elevated plus maze (EPM) were utilized to assess depression and anxiety-like behavior respectively. After behavioral evaluation on day 15th, their brain was isolated and assayed for catalase, superoxide dismutase, reduced glutathione, and malondialdehyde. There was a significant (p < 0.05) reduction in the seizure scores, anxiety and depression-like behaviors in mice from the 5th day of treatment. The antioxidant assays revealed significant (p < 0.05) increase in catalase and reduced glutathione, and significant (p < 0.05) reduction in lipid peroxidation in treated mice. This study provides evidence for the seizure reducing property of creatine and its ameliorating potential on anxiety and depressive-like behaviors that follows seizure episodes.

Silencing miR-20a-5p inhibits axonal growth and neuronal branching and prevents epileptogenesis through RGMa-RhoA-mediated synaptic plasticity.

Epileptogenesis is a potential process. Mossy fibre sprouting (MFS) and synaptic plasticity promote epileptogenesis. Overexpression of repulsive guidance molecule a (RGMa) prevents epileptogenesis by inhibiting MFS. However, other aspects underlying the RGMa regulatory process of epileptogenesis have not been elucidated. We studied whether RGMa could be modulated by microRNAs and regulated RhoA in epileptogenesis. Using microRNA databases, we selected four miRNAs as potential candidates. We further experimentally confirmed miR-20a-5p as a RGMa upstream regulator. Then, in vitro, by manipulating miR-20a-5p and RGMa, we investigated the regulatory relationship between miR-20a-5p, RGMa and RhoA, and the effects of this pathway on neuronal morphology. Finally, in the epilepsy animal model, we determined whether the miR-20a-5p-RGMa-RhoA pathway influenced MFS and synaptic plasticity and then modified epileptogenesis. Our results showed that miR-20a-5p regulated RGMa and that RGMa regulated RhoA in vitro. Furthermore, in primary hippocampal neurons, the miR-20a-5p-RGMa-RhoA pathway regulated axonal growth and neuronal branching; in the PTZ-induced epilepsy model, silencing miR-20a-5p prevented epileptogenesis through RGMa-RhoA-mediated synaptic plasticity but did not change MFS. Overall, we concluded that silencing miR-20a-5p inhibits axonal growth and neuronal branching and prevents epileptogenesis through RGMa-RhoA-mediated synaptic plasticity in the PTZ-induced epilepsy model, thereby providing a possible strategy to prevent epileptogenesis.

Mice Lacking Connective Tissue Growth Factor in the Forebrain Exhibit Delayed Seizure Response, Reduced C-Fos Expression and Different Microglial Phenotype Following Acute PTZ Injection.

Connective tissue growth factor (CTGF) plays important roles in the development and regeneration of the connective tissue, yet its function in the nervous system is still not clear. CTGF is expressed in some distinct regions of the brain, including the dorsal endopiriform nucleus (DEPN) which has been recognized as an epileptogenic zone. We generated a forebrain-specific Ctgf knockout (FbCtgf KO) mouse line in which the expression of Ctgf in the DEPN is eliminated. In this study, we adopted a pentylenetetrazole (PTZ)-induced seizure model and found similar severity and latencies to death between FbCtgf KO and WT mice. Interestingly, there was a delay in the seizure reactions in the mutant mice. We further observed reduced c-fos expression subsequent to PTZ treatment in the KO mice, especially in the hippocampus. While the densities of astrocytes and microglia in the hippocampus were kept constant after acute PTZ treatment, microglial morphology was different between genotypes. Our present study demonstrated that in the FbCtgf KO mice, PTZ failed to increase neuronal activity and microglial response in the hippocampus. Our results suggested that inhibition of Ctgf function may have a therapeutic potential in preventing the pathophysiology of epilepsy.

Antiepileptic Effects of Protein-Rich Extract from Bombyx batryticatus on Mice and Its Protective Effects against H2O2-Induced Oxidative Damage in PC12 Cells via Regulating PI3K/Akt Signaling Pathways.

Bombyx batryticatus is a known traditional Chinese medicine (TCM) utilized to treat convulsions, epilepsy, cough, asthma, headaches, and purpura in China for thousands of years. This study is aimed at investigating the antiepileptic effects of protein-rich extracts from Bombyx batryticatus (BBPs) on seizure in mice and exploring the protective effects of BBPs against H2O2-induced oxidative stress in PC12 cells and their underlying mechanisms. Maximal electroshock-induced seizure (MES) and pentylenetetrazole- (PTZ-) induced seizure in mice and the histological analysis were carried out to evaluate the antiepileptic effects of BBPs. The cell viability of PC12 cells stimulated by H2O2 was determined by MTT assay. The apoptosis and ROS levels of H2O2-stimulated PC12 cells were determined by flow cytometry analysis. Furthermore, the levels of malondialdehyde (MDA), superoxide dismutase (SOD), lactate dehydrogenase (LDH), and glutathione (GSH) in PC12 cells were assayed by ELISA and expressions of caspase-3, caspase-9, Bax, Bcl-2, PI3K, Akt, and p-Akt were evaluated by Western blotting and quantitative real-time polymerase chain reaction (RT-qPCR) assays. The results revealed that BBPs exerted significant antiepileptic effects on mice. In addition, BBPs increased the cell viability of H2O2-stimulated PC12 cells and reduced apoptotic cells and ROS levels in H2O2-stimulated PC12 cells. By BBPs treatments, the levels of MDA and LDH were reduced and the levels of SOD and GSH-Px were increased in H2O2-stimulated PC12 cells. Moreover, BBPs upregulated the expressions of PI3K, Akt, p-Akt, and Bcl-2, whereas they downregulated the expressions of caspase-9, caspase-3, and Bax in H2O2-stimulated PC12 cells. These findings suggested that BBPs possessed potential antiepileptic effects on MES and PTZ-induced seizure in mice and protective effects on H2O2-induced oxidative stress in PC12 cells by exerting antioxidative and antiapoptotic effects via PI3K/Akt signaling pathways.

The role of UCH-L1, MMP-9, and GFAP as peripheral markers of different susceptibility to seizure development in a preclinical model of epilepsy.

In our study, we assessed the potency of the brain-derived proteins ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), matrix metalloproteinase 9 (MMP-9), glial fibrillary acidic protein (GFAP) and the immune activation indicators interleukin 1ß (IL-1ß) and interleukin 6 (IL-6) as peripheral biomarkers of different susceptibilities to kindling in a preclinical model. We observed increased plasma UCH-L1 levels in kindled vs. control animals. Furthermore, MMP-9 and IL-1ß concentrations were the lowest in rats resistant to kindling. In summary, UCH-L1 is an indicator of neuronal loss and BBB disruption after seizure. MMP-9 and IL-1ß may indicate resistance to kindling. UCH-L1, MMP-9 and IL-1ß may have utility as peripheral biomarkers with translational potency in the clinic.

Blood-brain barrier dysfunction in canine epileptic seizures detected by dynamic contrast-enhanced magnetic resonance imaging.

OBJECTIVE: Dogs with spontaneous or acquired epilepsy exhibit resemblance in etiology and disease course to humans, potentially offering a translational model of the human disease. Blood-brain barrier dysfunction (BBBD) has been shown to partake in epileptogenesis in experimental models of epilepsy. To test the hypothesis that BBBD can be detected in dogs with naturally occurring seizures, we developed a linear dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) analysis algorithm that was validated in clinical cases of seizing dogs and experimental epileptic rats. METHODS: Forty-six dogs with naturally occurring seizures of different etiologies and 12 induced epilepsy rats were imaged using DCE-MRI. Six healthy dogs and 12 naive rats served as control. DCE-MRI was analyzed by linear-dynamic method. BBBD scores were calculated in whole brain and in specific brain regions. Immunofluorescence analysis for transforming growth factor beta (TGF-ß) pathway proteins was performed on the piriform cortex of epileptic dogs. RESULTS: We found BBBD in 37% of dogs with seizures. A significantly higher cerebrospinal fluid to serum albumin ratio was found in dogs with BBBD relative to dogs with intact blood-brain barrier (BBB). A significant difference was found between epileptic and control rats when BBBD scores were calculated for the piriform cortex at 48 hours and 1 month after status epilepticus. Mean BBBD score of the piriform lobe in idiopathic epilepsy (IE) dogs was significantly higher compared to control. Immunohistochemistry results suggested active TGF-ß signaling and neuroinflammation in the piriform cortex of dogs with IE, showing increased levels of serum albumin colocalized with glial acidic fibrillary protein and pSMAD2 in an area where BBBD had been detected by linear DCE-MRI. SIGNIFICANCE: Detection of BBBD in dogs with naturally occurring epilepsy provides the ground for future studies for evaluation of novel treatment targeting the disrupted BBB. The involvement of the piriform lobe seen using our linear DCE-MRI protocol and algorithm emphasizes the possibility of using dogs as a translational model for the human disease.

Effect of acute caffeine administration on PTZ-induced seizure threshold in mice: Involvement of adenosine receptors and NO-cGMP signaling pathway.

PURPOSE: Caffeine is a non-selective antagonist of A1 and A2A adenosine receptors (ARs). In this regard, nitric oxide (NO) is partly involved in the central effects of caffeine. In this study, we examined the effect of acute caffeine administration on pentylenetetrazole (PTZ)-induced seizure threshold by focusing on A1Rs, A2ARs, and NO-cGMP signaling pathway. METHODS: NMRI male mice (25-30 g) received caffeine (5, 50, and 100 mg/kg) alone, whereas 8-CPT (1 and 5 mg/kg, a selective A1Rs antagonist), SCH-442416 (5 and 10 mg/kg, a selective A2ARs antagonist) or sildenafil (5 and 10 mg/kg, a phosphodiesterase 5 inhibitor) were administrated alone or as pre-treatment before caffeine. Seizure threshold was assessed by intravenous infusion of PTZ. Nitric oxide metabolites (NOx) were measured with the Griess method. RESULTS: When administrated alone, caffeine (5 and 50 mg/kg) and 8-CPT (1 and 5 mg/kg) significantly decreased seizure threshold, while 100 mg/kg of caffeine, SCH-442416 or sildenafil did not change it. Only pre-treatment with SCH-442416 (5 and 10 mg/kg) or sildenafil (5 and 10 mg/kg) before 100 mg/kg of caffeine significantly decreased seizure threshold. Moreover, NOx levels significantly decreased following alone administration of caffeine (100 mg/kg) or 8-CPT (5 mg/kg). CONCLUSION: The results of present study showed that 5 and 50 mg/kg of caffeine had a proconvulsant effect but caffeine at a dose of 100 mg/kg had no effect on seizure threshold. In addition, it seems that the effect caffeine on seizure threshold is partly mediated through ARs or modulation of the NO-cGMP signaling pathway.

Pycnogenol Protects against Pentylenetetrazole-Induced Oxidative Stress and Seizures in Mice.

BACKGROUND: Epilepsy is one of the most common and severe brain disorders in the world, characterized by recurrent spontaneous seizures due to an imbalance between cerebral excitability and inhibition. Oxidative stress is a biochemical state in which reactive oxygen species are generated and associated with various diseases including epilepsy. Pycnogenol, a polyphenol obtained from the pine tree and has antioxidant & anti-inflammatory activity. So, the aim of the study was to evaluate the effect of Pycnogenol on pentylenetetrazole (PTZ)-induced seizures in mice. METHODS: The mice of swiss strain each weighing 18-30g were used. Pycnogenol (50&100mg/kg) was suspended in carboxymethyl cellulose in saline and administered orally. Diazepam (1mg/kg, i.p) was used as a standard drug. The anticonvulsant effects of the drugs were measured using PTZ and cognitive behaviour was also assessed. The biochemical estimation was done by measuring Thiobarbituric acid, Superoxide dismutase, Catalase, and reduced glutathione followed by the histopathological study. RESULT: Pycnogenol 50 & 100mg/kg showed a significant increase in latency to PTZ-induced seizures, decrease in duration and frequency of convulsions compared to control animals; however, the effects were dose-dependent and were more significant at a higher dose. No impairment in cognitive functions like memory and muscle relaxant was observed following pycnogenol 50 & 100 mg/kg. The effect of Pycnogenol on biochemical parameter was found to be significant. It significantly (p<0.01) decreases the level of TBARS and increases the levels of SOD, catalase, and GSH in the brain tissue. The histopathological evaluation showed less neuronal degeneration in the brain due to PTZ-induced seizures in comparison to control group. CONCLUSION: Thus pycnogenol has a protective approach towards convulsion and can be included as an adjuvant therapy with antiepileptic drugs.

Vitamin D protects against hippocampal apoptosis related with seizures induced by kainic acid and pentylenetetrazol in rats.

OBJECTIVES: The hippocampus is susceptible to damage in patients with epilepsy and in animals with seizures caused by excitotoxic agents. The effect of vitamin D on hippocampal apoptosis related with seizures has not been reported. However, epileptic patients have an increased risk of hypovitaminosis D which is most likely due to the effects of antiepileptic drugs. Therefore, in this study, it was aimed to evaluate the effects of vitamin D on hippocampal apoptosis related with seizures by using pentylenetetrazol (PTZ) and kainic acid (KA) in rats. METHODS: Male Sprague Dawley rats, aged 5.5 weeks, were randomly divided into six groups: control, vitamin D, PTZ, KA, PTZ + vitamin D and KA + vitamin D groups. The groups that received vitamin D were given 500 IU/kg of vitamin D daily for two weeks in addition to a standard diet. At the end of this period, PTZ and KA were applied to trigger seizures in the rats in the seizure groups. 24 h after the administration of PTZ and KA, the rats were decapitated. In the hippocampal region, apoptosis was assessed by TUNEL and brain-derived neurotrophic factor (BDNF), Bax, caspase-3 and c-fos activation were evaluated by immunohistochemical method. RESULTS: BDNF level increased while c-fos, Bax and caspase-3 levels decreased (p < 0.0001, in all) in the hippocampal neurons of the groups that were pre-treated with vitamin D before the administration of PTZ and KA, in comparison with the PTZ and KA groups. Vitamin D significantly decreased the number of apoptotic cells in these rats in comparison with the PTZ and KA groups (p < 0.0001). CONCLUSION: This study indicates that vitamin D has neuroprotective effects on hippocampal apoptosis induced by PTZ and KA in rats. With this study it is suggested that keeping vitamin D levels within normal limits may be beneficial for patients with epilepsy, especially children.

Bioluminescence imaging of Arc expression in mouse brain under acute and chronic exposure to pesticides.

Exposure to pesticides can induce neurobehavioral effects in rodents, as well as in other mammals, including humans. However, the effects of the toxicity of pesticides on the central nervous system (CNS) remain largely unclear. The expression of the activity-regulated cytoskeleton-associated protein gene (Arc) is induced in a neuronal-activity-dependent manner and is implicated in synaptic and experience-dependent plasticity. We previously developed Arc-promoter-driven luciferase transgenic (Tg) mouse strains to monitor the neuronal-activity-dependent gene expression under physiological and pathological conditions in vivo. In this study, we examined the effect of acute administration of four different pesticides (deltamethrin, glufosinate, methylcarbaryl, and imidacloprid) on neuronal activity using Arc-Luc Tg mice. The change in the bioluminescence signal in mouse brain upon treatment with deltamethrin and glufosinate occurred more slowly than that of kainic acid, a potent neuroexcitatory amino acid agonist. These two pesticides also caused convulsive responses in adult Arc-Luc Tg mice. In the case of glufosinate, we detected the long-term upregulation of bioluminescence signal intensity of Arc-Luc over 24 h after the treatment. Furthermore, we observed greater changes of bioluminescence signal in adults than in juveniles, and a lower incidence of convulsions at the juvenile stage. In contrast to the acute treatment, we detected a decrease of bioluminescence signal after low-dose chronic treatment with glufosinate, without neuronal overexcitation. From these results, we suggest that Arc-Luc Tg mice are useful for assessing the acute and chronic effects of pesticides on the CNS.

NLRP3 Inflammasome Activation Leads to Epileptic Neuronal Apoptosis.

BACKGROUND: While the NOD-Like Receptor Protein-3 (NLRP3) inflammasome is involved in a variety of nervous system diseases, its role in epilepsy still needs to be further investigated. METHODS: The expressions of NLRP3 inflammasome and apoptosis related proteins were examined by Western blot. MTT was used to assess cell viability. The role of NLRP3 inflammasome in epileptic neuronal apoptosis was further validated in NLRP3 knockout (KO) mice by Nissl staining. RESULTS: Exposure of SH-SY5Y cells to free-Mg2+ solutions increased the expression of NLRP3 inflammasome with a concomitant increase in neuronal apoptosis. This effect was inhibited in cells treated with MCC950 as a common NLRP3 inhibitor, thereby implicating the role of NLRP3 inflammasome in epileptic neuronal apoptosis. In vivo relevance of this finding was further corroborated in the NLRP3 KO mice. Compared with the wild type mice, neuronal loss induced by pentylenetetrazole was significantly inhibited in the NLRP3 KO mice. CONCLUSION: The study presented herein demonstrates the interaction between NLRP3 inflammasome and epilepsy progression. In addition, MCC950 might represent an important therapeutic drug for the treatment of NLRP3 inflammasome driven epileptogenic activity.

Effect of valproic acid alone or combined with low dose gamma irradiation in modulating PTZ-induced convulsions in rats involving AKT/m-TOR pathway.

AIM: The current study evaluates the anticonvulsant effect of valproic acid (VPA) alone or combined with low dose γ-irradiation (LDR) against pentylenetetrazol-induced convulsions in rats. MATERIAL AND METHODS: Five groups of rats were used, group I served as normal control, group II served as PTZ- control and the other three groups were pretreated with single LDR(o.5 Gy), VPA(150 mg/kg i.p.5 days) and VPA with LDR respectively before PTZ injection. Racine score, latency and duration of convulsions were assessed. Evaluation of brain neurotransmitters (glutamate and GABA) as well as AKT/m-TOR pathway (protein kinase B [AKT], mammalian target of rapamycin [m-TOR], protein S6 and caspase 3). Measurement of oxidative stress (Malondialdehyde, glutathione and nitric oxide) was carried out. Histopathological examinations of hippocampi were done. KEY FINDINGS: PTZ resulted in behavioural changes (high Racine score, long seizure duration and short latency).PTZ enhanced oxidative stress state (high MDA and NO, as well as low GSH) compared to normal control. VPA alone or combined with LDR ameliorated, the convulsions and caused significant improvement in behavioural changes and other tested parameters compared to normal control. Histopathological examination of hippocampi was carried out to adjoin the biochemical changes. Certain changes were observed after PTZ injection. However, normal pictures of the other tested groups. SIGNIFICANCE: The previously mentioned findings support that LDR purveyed novel anticonvulsant activity which could offer a possible contributor in the basic treatment of convulsions. This effect might be due to modulation of AkT/m-TOR pathway, reduction of oxidative stress and modulation of neurotransmitters.

Neurochemical properties of neurospheres infusion in experimental-induced seizures.

Cell replacement through neural stem cells has been a promising alternative therapy for neurodegenerative diseases. It was evaluated the possible protect and/or prevent role of neurospheres in experimental models of epilepsy by the use of biomarkers of oxidative stress and histopathological analysis. After 1 h of the epileptic inductions by pilocarpine, pentylenotetrazole and picrotoxin, rats were infused with a suspension of 2 × 106 cells/0.25 mL, marked with Qtracker® 655, via caudal vein. In the control group epilepsy was not induced, but received the cell infusion under the same conditions of other groups. After 30 days, the rats were euthanized, and the removal of the brain was proceeded to later perform the assays oxidative stress and histopathology analysis. Thiobarbituric acid and nitrite levels were elevated in epileptic groups treated with neurospheres, and the levels of reduced glutathione, superoxide dismutase and catalase were reduced when compared to non-treated groups. The performance of oxidative enzymes from pilocarpine group treated with neurospheres showed slight increase. Histopathological evaluation observed distribution of neurospheres throughout the brain tissue, with viable cells and in process of differentiation in the pilocarpine group, but with differentiation and regeneration compromised in epilepsy by picrotoxin and pentylenetetrazole due to a microenvironment of oxidative stress. Neural stem cell therapy has a promising potential for protection in the pilocarpine epilepsy model, suggesting that the antioxidant system of neurospheres could reduce oxidative damage generated by seizure.

Anticonvulsant effects after grafting of rat, porcine, and human mesencephalic neural progenitor cells into the rat subthalamic nucleus.

Cell transplantation based therapy is a promising strategy for treating intractable epilepsies. Inhibition of the subthalamic nucleus (STN) or substantia nigra pars reticulata (SNr) is a powerful experimental approach for remote control of different partial seizure types, when targeting the seizure focus is not amenable. Here, we tested the hypothesis that grafting of embryonic/fetal neural precursor cells (NPCs) from various species (rat, human, pig) into STN or SNr of adult rats induces anticonvulsant effects. To rationally refine this approach, we included NPCs derived from the medial ganglionic eminence (MGE) and ventral mesencephalon (VM), both of which are able to develop a GABAergic phenotype. All VM- and MGE-derived cells showed intense migration behavior after grafting into adult rats, developed characteristics of inhibitory interneurons, and survived at least up to 4 months after transplantation. By using the intravenous pentylenetetrazole (PTZ) seizure threshold test in adult rats, transient anticonvulsant effects were observed after bilateral grafting of NPCs derived from human and porcine VM into STN, but not after SNr injection (site-specificity). In contrast, MGE-derived NPCs did not cause anticonvulsant effects after grafting into STN or SNr (cell-specificity). Neither induction of status epilepticus by lithium-pilocarpine to induce neuronal damage prior to the PTZ test nor pretreatment of MGE cells with retinoic acid and potassium chloride to increase differentiation into GABAergic neurons could enhance anticonvulsant effectiveness of MGE cells. This is the first proof-of-principle study showing anticonvulsant effects by bilateral xenotransplantation of NPCs into the STN. Our study highlights the value of VM-derived NPCs for interneuron-based cell grafting targeting the STN.

Ketogenic diet regulates the antioxidant catalase via the transcription factor PPARγ2.

We have previously found that the transcription factor PPARγ2 contributes to the mechanism of action of the ketogenic diet (KD), an established treatment for pediatric refractory epilepsy. Among the wide-array of genes regulated by PPARγ, previous studies have suggested that antioxidants such as catalase may have prominent roles in KD neuroprotective and antiseizure effects. Here, we tested the hypothesis that the KD increases catalase through activation of PPARγ2, and that this action is part of the mechanism of antiseizure efficacy of the KD. We determined catalase mRNA and protein expression in hippocampal tissue from epileptic Kcna1-/- mice, Pparγ2+/+ mice and Pparγ2-/- mice. We found that a KD increases hippocampal catalase expression in Kcna1-/- and Pparγ2+/+ mice, but not Pparγ2-/- mice. Next, we determined whether catalase contributes to KD seizure protection. We found that the KD reduces pentylenetetrazole (PTZ)-induced seizures; however, pretreatment with a catalase inhibitor occluded KD effects on PTZ seizures. These results suggest that the KD regulates catalase expression through PPARγ2 activation, and that catalase may contribute to the KD antiseizure efficacy.

Neuroanatomical Localization of Galanin in Zebrafish Telencephalon and Anticonvulsant Effect of Galanin Overexpression.

Galanin is a neuropeptide widely expressed in the nervous system, but it is also present in non-neuronal locations. In the brain, galanin may function as an inhibitory neurotransmitter. Several studies have shown that galanin is involved in seizure regulation and can modulate epileptic activity in the brain. The overall goal of the study was to establish zebrafish as a model to study the antiepileptic effect of galanin. The goal of this study was achieved by (1) determining neuroanatomical localization of galanin in zebrafish lateral pallium, which is considered to be the zebrafish homologue of the mammalian hippocampus, the brain region essential for initiation of seizures, and (2) testing the anticonvulsant effect of galanin overexpression. Whole mount immunofluorescence staining and pentylenotetrazole (PTZ)-seizure model in larval zebrafish using automated analysis of motor function and qPCR were used in the study. Immunohistochemical staining of zebrafish larvae revealed numerous galanin-IR fibers innervating the subpallium, but only scarce fibers reaching the dorsal parts of telencephalon, including lateral pallium. In three-month old zebrafish, galanin-IR innervation of the telencephalon was similar; however, many more galanin-IR fibers reached the dorsal telencephalon, but in the lateral pallium only scarce galanin-IR fibers were visible. qRT-PCR revealed, as expected, a strong increase in the expression of galanin in the Tg(hsp70l:galn) line after heat shock; however, also without heat shock, the galanin expression was several-fold higher than in the control animals. Galanin overexpression resulted in downregulation of c-fos after PTZ treatment. Behavioral analysis showed that galanin overexpression inhibited locomotor activity in PTZ-treated and control larvae. The obtained results show that galanin overexpression reduced the incidence of seizure-like behavior episodes and their intensity but had no significant effect on their duration. The findings indicate that in addition to antiepileptic action, galanin modulates arousal behavior and demonstrates a sedative effect. The current study showed that galanin overexpression correlated with a potent anticonvulsant effect in the zebrafish PTZ-seizure model.

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

BACKGROUND: Epilepsy is a common neurological disorder and is not well controlled by available antiepileptic drugs (AEDs). Inflammation is considered to be a critical factor in the pathophysiology of epilepsy. Sinomenine (SN), a bioactive alkaloid with anti-inflammatory effect, exerts neuroprotective activity in many nervous system diseases. However, little is known about the effect of SN on epilepsy. METHODS: The chronic epilepsy model was established by pentylenetetrazole (PTZ) kindling. Morris water maze (MWM) was used to test spatial learning and memory ability. H.E. staining and Hoechst 33258 staining were used to evaluate hippocampal neuronal damage. The expression of nucleotide oligomerization domain (NOD)-like receptor protein 1 (NLRP1) inflammasome complexes and the level of inflammatory cytokines were determined by western blot, quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA) kits. RESULTS: SN (20, 40, and 80 mg/kg) dose-dependently disrupts the kindling acquisition process, which decreases the seizure scores and the incidence of fully kindling. SN also increases the latency of seizure and decreases the duration of seizure in fully kindled rats. In addition, different doses of SN block the hippocampal neuronal damage and minimize the impairment of spatial learning and memory in PTZ kindled rats. Finally, PTZ kindling increases the expression of NLRP1 inflammasome complexes and the levels of inflammatory cytokines IL-1ß, IL-18, IL-6, and TNF-α, which are all attenuated by SN in a dose- dependent manner. CONCLUSIONS: SN exerts anticonvulsant and neuroprotective activity in PTZ kindling model of epilepsy. Disrupting the kindling acquisition, which inhibits NLRP1 inflammasome-mediated inflammatory process, might be involved in its effects.

Neuronal adenosine A2A receptor overexpression is neuroprotective towards 3-nitropropionic acid-induced striatal toxicity: a rat model of Huntington's disease.

The A2A adenosine receptor (A2AR) is widely distributed on different cellular types in the brain, where it exerts a broad spectrum of pathophysiological functions, and for which a role in different neurodegenerative diseases has been hypothesized or demonstrated. To investigate the role of neuronal A2ARs in neurodegeneration, we evaluated in vitro and in vivo the effect of the neurotoxin 3-nitropropionic acid (3-NP) in a transgenic rat strain overexpressing A2ARs under the control of the neural-specific enolase promoter (NSEA2A rats). We recorded extracellular field potentials (FP) in corticostriatal slice and found that the synaptotoxic effect of 3-NP was significantly reduced in NSEA2A rats compared with wild-type animals (WT). In addition, after exposing corticostriatal slices to 3-NP 10 mM for 2 h, we found that striatal cell viability was significantly higher in NSEA2A rats compared to control rats. These in vitro results were confirmed by in vivo experiments: daily treatment of female rats with 3-NP 10 mg/kg for 8 days induced a selective bilateral lesion in the striatum, which was significantly reduced in NSEA2A compared to WT rats. These results demonstrate that the overexpression of the A2AR selectively at the neuronal level reduced 3-NP-induced neurodegeneration, and suggest an important function of the neuronal A2AR in the modulation of neurodegeneration.