Glycogen synthase kinase-3 (GSK-3) is ubiquitously expressed throughout the brain and involved in vital molecular pathways such as cell survival and synaptic reorganization and has emerged as a potential drug target for brain diseases. A causal role for GSK-3, in particular the brain-enriched GSK-3β isoform, has been demonstrated in neurodegenerative diseases such as Alzheimer’s and Huntington’s, and in psychiatric diseases. Recent studies have also linked GSK-3 dysregulation to neuropathological outcomes in epilepsy. To date, however, there has been no genetic evidence for the involvement of GSK-3 in seizure-induced pathology. Status epilepticus (prolonged, damaging seizure) was induced via a microinjection of kainic acid into the amygdala of mice. Studies were conducted using two transgenic mouse lines: a neuron-specific GSK-3β overexpression and a neuron-specific dominant-negative GSK-3β (GSK-3β-DN) expression in order to determine the effects of increased or decreased GSK-3β activity, respectively, on seizures and attendant pathological changes in the hippocampus. GSK-3 inhibitors were also employed to support the genetic approach. Status epilepticus resulted in a spatiotemporal regulation of GSK-3 expression and activity in the hippocampus, with decreased GSK-3 activity evident in non-damaged hippocampal areas. Consistent with this, overexpression of GSK-3β exacerbated status epilepticus-induced neurodegeneration in mice. Surprisingly, decreasing GSK-3 activity, either via overexpression of GSK-3β-DN or through the use of specific GSK-3 inhibitors, also exacerbated hippocampal damage and increased seizure severity during status epilepticus. In conclusion, our results demonstrate that the brain has limited tolerance for modulation of GSK-3 activity in the setting of epileptic brain injury. These findings caution against targeting GSK-3 as a treatment strategy for epilepsy or other neurologic disorders where neuronal hyperexcitability is an underlying pathomechanism.

Seizures are common during the neonatal period, often due to hypoxic-ischemic encephalopathy and may contribute to acute brain injury and the subsequent development of cognitive deficits and childhood epilepsy. Here we explored short- and long-term consequences of neonatal hypoxia-induced seizures in 7 day old C57BL/6J mice. Seizure activity, molecular markers of hypoxia and histological injury were investigated acutely after hypoxia and response to chemoconvulsants and animal behaviour was explored at adulthood. Hypoxia was induced by exposing pups to 5% oxygen for 15 min (global hypoxia). Electrographically defined seizures with behavioral correlates occurred in 95% of these animals and seizures persisted for many minutes after restitution of normoxia. There was minimal morbidity or mortality. Pre- or post-hypoxia injection of phenobarbital (50mg/kg) had limited efficacy at suppressing seizures. The hippocampus from neonatal hypoxia-seizure mice displayed increased expression of vascular endothelial growth factor and the immediate early gene c-fos, minimal histological evidence of cell injury and activation of caspase-3 in scattered neurons. Behavioral analysis of mice five weeks after hypoxia-induced seizures detected novel anxiety-related and other behaviors, while performance in a spatial memory test was similar to controls. Seizure threshold tests with kainic acid at six weeks revealed that mice previously subject to neonatal hypoxia-induced seizures developed earlier, more frequent and longer-duration seizures. This study defines a set of electro-clinical, molecular, pharmacological and behavioral consequences of hypoxia-induced seizures that indicate short- and long-term deleterious outcomes and may be a useful model to investigate the pathophysiology and treatment of neonatal seizures in humans.

You are free: • to copy, distribute, display, and perform the work. • to make derivative works. Under the following conditions: • Attribution — You must give the original author credit. • Non-Commercial — You may not use this work for commercial purposes. • Share Alike — If you alter, transform, or build upon this work, you may distribute the resulting work only under a licence identical to this one. For any reuse or distribution, you must make clear to others the licence terms of this work. Any of these conditions can be waived if you get permission from the author. Your fair use and other rights are in no way affected by the above. 3 Summary Recent reports have shown that the selective dopamine D 1-like agonist SKF 83822 [which stimulates adenylate cyclase, but not phospholipase C] induces prominent behavioral seizures in mice, whereas its benzazepine congener SKF 83959 [which stimulates phospholipase C, but not adenylate cyclase] does not. To investigate the relative involvement of D 1 vs D 5 receptors in mediating seizures, ethological behavioral topography and cortical EEGs were recorded in D 1 , D 5 and DARPP-32 knockout mice in response to a convulsant dose of SKF 83822. SKF 83822-induced behavioral and EEG seizures were gene dose-dependently abolished in D 1 knockouts. In both heterozygous and homozygous D 5 knockouts, the latency to first seizure was significantly increased and total EEG seizures were reduced relative to wild-types. The majority (60%) of homozygous DARPP-32 knockouts did not have seizures; of those having seizures (40%), the latency to first seizure was significantly increased and the number of high amplitude, high frequency polyspike EEG events was reduced. In addition, immunoblotting was performed to investigate downstream intracellular signalling mechanisms at D 1-like receptors following challenge with SKF 83822 and SKF 83959. In wild-types administered SKF 83822, levels of ERK1/2 and GluR1 AMPA receptor phosphorylation increased twofold in both the striatum and hippocampus; in striatal slices DARPP-32 phosphorylation at Thr34 increased five-fold relative to vehicle-treated controls. These findings indicate that D 1 , and to a lesser extent D 5 , receptor coupling to DARPP-32, ERK1/2 and glutamatergic signalling is involved in mediating the convulsant effects of SKF 83822.

Status epilepticus in the adult brain invariably causes an increase in hippocampal neurogenesis and the appearance of ectopic cells and this has been implicated as a causal factor in epileptogenesis. The effect of status epilepticus on neurogenesis in the developing brain is less well characterized and models of early-life seizures typically do not reproduce the hippocampal damage common to human mesial temporal sclerosis. We recently reported that evoking status epilepticus by intra-amygdala microinjection of kainic acid in post-natal (P) day 10 rats caused substantial acute neuronal death within the ipsilateral hippocampus and rats later developed unilateral hippocampal sclerosis and spontaneous recurrent seizures. Here, we examined the expression of a selection of genes associated with neurogenesis and assessed neurogenic function in this model. Protein levels of several markers of neurogenesis including polysialic acid neural cell adhesion molecule, neuroD and doublecortin were reduced in the hippocampus three days after status epilepticus in P10 rats. In contrast, protein levels of neurogenesis markers were similar to control in rats at P55. Pulse-chase experiments using thymidine analogues suggested there was a reduction in new neurons at 72 h after status epilepticus in P10 rats, whereas numbers of new neurons labelled in epileptic rats at P55 with hippocampal sclerosis were similar to controls. The present study suggests that status epilepticus in the immature brain suppresses neurogenesis but the neurogenic potential is retained in animals that later develop hippocampal sclerosis.

Dopamine D2 receptor (D2R) signalling has been shown to modulate seizure-induced hippocampal cell death. D2R knockout (D2R−/−) mice are more susceptible to kainic acid (KA)-induced excitotoxicity, displaying cell death in the CA3 subfield of the hippocampus at KA doses not damaging in wild-type (WT) animals. Absence of D2R signalling in the hippocampus leads to activation (dephosphorylation) of glycogen synthase kinase 3β (GSK-3β) after KA (20 mg/kg), which is not associated with a change in the phosphorylation of the GSK-3β regulator Akt at the canonical threonine 308 residue. In the present study, we investigated alternative pathways responsible for the activation of GSK-3β in the hippocampus of the D2R−/− mice 24 h following KA-induced seizures. Here, we show that phosphorylation of Akt occurs at serine 473 (Ser473) in the CA3 region of WT but not D2R−/− mice following KA. Moreover, the CA1 subregion, which does not undergo neurodegeneration in either WT or D2R−/− mice, displays a strong induction of Akt (Ser473) phosphorylation after KA. Additionally, the vulnerability in the CA3 is not associated with changes to p38MAPK and Dishevelled activation, and β-catenin does not appear to be a downstream target of the GSK-3β. Thus, we propose that GSK-3β phosphorylation-mediated hippocampal cell survival may depend on Akt (Ser473) phosphorylation; loss of D2R-mediated signalling in the CA3 region of D2R−/− mice leads to reduced Akt (Ser473) phosphorylation rendering neurons more vulnerable to apoptosis. Further investigation is required to fully elucidate the GSK-3β targets involved in D2R-dependent response to excitotoxicity.

FOXO3a is member of the Forkhead box class O transcription factors, which functions in diverse pathways to regulate cellular metabolism, differentiation, and apoptosis. FOXO3a shuttles between the cytoplasm and nucleus and may be activated in neurons by stressors, including seizures. A subset of nuclear transcription factors may localize to mitochondria, but whether FOXO3a is present within brain mitochondria is unknown. Here, we report that purified mitochondrial fractions from rat, mouse, and human hippocampus, as well as HT22 hippocampal cells, contain FOXO3a protein. Immunogold electron microscopy supported the presence of FOXO3a within brain mitochondria, and chromatin immunoprecipitation analysis suggested FOXO3a was associated with mitochondrial DNA. Over-expression of a mitochondrially targeted FOXO3a fusion protein in HT22 cells, but not primary hippocampal neurons, conferred superior protection against glutamate toxicity than FOXO3a alone. Mitochondrial FOXO3a levels were reduced in the damaged region of the mouse hippocampus after status epilepticus, while mitochondrial fractions from the hippocampus of patients with temporal lobe epilepsy displayed higher levels of FOXO3a than controls. These results support mitochondria as a site of FOXO3a localization, which may contribute to the overall physiological and pathophysiological functions of this transcription factor.

Epilepsy is a complex disease, characterized by the repeated occurrence of bursts of electrical activity (seizures) in specific brain areas. The behavioral outcome of seizure events strongly depends on the brain regions that are affected by overactivity. Here we review the intracellular signaling pathways involved in the generation of seizures in epileptogenic areas. Pathways activated by modulatory neurotransmitters (dopamine, norepinephrine, and serotonin), involving the activation of extracellular-regulated kinases and the induction of immediate early genes (IEGs) will be first discussed in relation to the occurrence of acute seizure events. Activation of IEGs has been proposed to lead to long-term molecular and behavioral responses induced by acute seizures. We also review deleterious consequences of seizure activity, focusing on the contribution of apoptosis-associated signaling pathways to the progression of the disease. A deep understanding of signaling pathways involved in both acute- and long-term responses to seizures continues to be crucial to unravel the origins of epileptic behaviors and ultimately identify novel therapeutic targets for the cure of epilepsy.

Autism spectrum disorders (ASD) and epilepsy are among the most devastating and common neurological disorders of childhood, with an estimated incidence of about 0.5 – 1% in worldwide population. Autism and epilepsy are often associated: about 30% of autistic patients develop epilepsy, and a relevant percentage of epileptic patients in paediatric age shows ASD symptoms. This suggests that – at least in certain cases – common neurodevelopmental bases may exist for these two diseases (Brooks-Kayal, 2010). The neurodevelopmental bases of both autism and epilepsy have been clearly showed by a number of clinical, neuroimaging and neuropathological studies. A large series of evidence also indicates that both autism and epilepsy have a primarily genetic origin. A wide variety of genes have been associated to these diseases, including genes regulating brain development, gene transcription, synaptic scaffolding, neurotransmission and signal transduction. Indeed, genetic heterogeneity is recognised as a typical feature of both autism and epilepsy, meaning that different mutations may result in similar disease phenotypes. Since autism and epilepsy are neurological disorders involving multiple genes and resulting in complex pathological traits, understanding the underlying mechanisms is a very difficult task. Moreover, even though the two diseases may have a common neurodevelopmental origin, a precise link between these two pathologies still remains to be determined. In recent years, inhibitory circuit dysfunction gained increasing attention in ASD research. ┛-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the brain, and human genetics studies clearly indicate an association between ASD and genes for GABA receptor subunits as well as genes controlling GABAergic neuron development or GABAergic synapse structure. Moreover, recent studies, performed on both animal models and postmortem human samples, suggest that GABAergic neurons and circuits may be altered in ASD. It is likely that the imbalance between excitation and inhibition resulting from neurodevelopmental defects in GABAergic circuitry might represent a common cause for ASD and epilepsy. Here, we will review the genetic, cellular, anatomical and neurophysiological studies that support this hypothesis.

Autism spectrum disorders (ASD) and epilepsy are very common neurological disorders of childhood, with an estimated incidence of about 0.5 - 1 % in worldwide population. ASD and epilepsy are often associated, suggesting that common neurodevelopmental bases may exist for these two disorders. The neurodevelopmental bases of both ASD and epilepsy have been clearly showed by a number of genetic, neuroimaging and neuropathological studies. In recent years, dysfunction of inhibitory GABAergic circuits has been proposed as a cause for both disorders. Several studies performed on both animal models and postmortem human samples indicate that GABAergic neurons and circuits are altered in both ASD and epilepsy, suggesting that the excitation/inhibition imbalance resulting from neurodevelopmental defects in GABAergic circuitry might represent a common pathogenetic mechanism for these disorders. Here, we will review the most significant studies supporting this hypothesis.

Activation of dopamine D1 receptors (D1Rs) has been shown to induce epileptiform activity. We studied the molecular changes occurring in the hippocampus in response to the administration of the D1-type receptor agonist, SKF 81297. SKF 81297 at 2.5 and 5.0 mg/kg induced behavioural seizures. Electrophysiological recordings in the dentate gyrus revealed the presence of epileptiform discharges peaking at 30-45 min post-injection and declining by 60 min. Seizures were prevented by the D1-type receptor antagonist, SCH 23390, or the cannabinoid CB1 receptor agonist, CP 55,940. The effect of SKF 81297 was accompanied by increased phosphorylation of the extracellular signal-regulated protein kinases 1 and 2 (ERK), in the granule cells of the dentate gyrus. This effect was also observed in response to administration of other D1-type receptor agonists, such as SKF83822 and SKF83959. In addition, SKF 81297 increased the phosphorylation of the ribosomal protein S6 and histone H3, two downstream targets of ERK. These effects were prevented by genetic inactivation of D1Rs, or by pharmacological inhibition of ERK. SKF 81297 was also able to enhance the levels of Zif268 and Arc/Arg3.1, two immediate early genes involved in transcriptional regulation and synaptic plasticity. These changes may be involved in forms of activity-dependent plasticity linked to the manifestation of seizures and to the ability of dopamine to affect learning and memory.

Mesial temporal lobe epilepsy (MTLE) is the most common form of intractable seizure disorder in adults. It is associated with an asymmetrical pattern of neuron loss within the hilus and CA1 hippocampal subfields, with relative sparing of the dentate granule neurons and the CA2 subfields. The amygdalar nuclei and the cortical neurons are other areas that are rarely involved in MTLE.1 The neuropathological changes that bring about focally evoked seizures in the adult are thought to begin in the early stages of neonatal life. A wide range of factors have been implicated in the causation of MTLE, such as febrile seizures and traumatic brain injury.2 Some studies indicate that up to 74% of those who experience early life status epilepticus develop epilepsy at a later stage.2 The objective of this study is to investigate the neuropathological changes induced by intra-amygdalar kainic acid (KA) microinjection in a postnatal day 10 (P10) rat model of MTLE.3

Abstract Background: Strengthening exercise for gluteus medius (GMed) is an important management strategy for lower limb disorders such as osteoarthritis and patello-femoral syndrome, and exercises in functional positions are commonly prescribed. Electromyography (EMG) can be used to measure muscle activation to ascertain the extent of muscle recruitment during exercise. Objectives: To review the available evidence on the magnitude of GMed activation measured with EMG during therapeutic exercise. Methods: A structured review of studies which measured EMG magnitude of GMed during a range of therapeutic exercises was undertaken. Amplitude levels of GMed were reported as a percentage of maximum voluntary isometric contraction. Results: Fifteen studies were included. Most of these were conducted on asymptomatic volunteers, with three studies investigating individuals with knee or hip pathology. A wide range of exercises was investigated in both weightbearing (WB) and nonweightbearing (NWB) positions. In general, EMG activation was greater in WB positions but variation occurred across studies. Many exercises were below levels considered necessary for strength gains. Generally, methodological quality was good but there was variation in the reporting of technical aspects of the study. Many of the studies did not acknowledge the range of limitations of EMG in measuring muscle activation in therapeutic exercise. Conclusions: The results provide some information regarding GMed recruitment during exercise, although there were some discrepancies in results between studies which may be due to factors related to EMG measurement and recording as well as the execution of the exercise. Extrapolation of results to symptomatic populations in a clinical setting islimited.

Background: Strengthening exercise for gluteus medius (GMed) is an important management strategy for lower limb disorders such as osteoarthritis and patello-femoral syndrome, and exercises in functional positions are commonly prescribed. Electromyography (EMG) can be used to measure muscle activation to ascertain the extent of muscle recruitment during exercise.Objectives: To review the available evidence on the magnitude of GMed activation measured with EMG during therapeutic exercise.Methods: A structured review of studies which measured EMG magnitude of GMed during a range of therapeutic exercises was undertaken. Amplitude levels of GMed were reported as a percentage of maximum voluntary isometric contraction.Results: Fifteen studies were included. Most of these were conducted on asymptomatic volunteers, with three studies investigating individuals with knee or hip pathology. A wide range of exercises was investigated in both weightbearing (WB) and nonweightbearing (NWB) positions. In general, EMG activation was greater in WB positions but variation occurred across studies. Many exercises were below levels considered necessary for strength gains. Generally, methodological quality was good but there was variation in the reporting of technical aspects of the study. Many of the studies did not acknowledge the range of limitations of EMG in measuring muscle activation in therapeutic exercise.Conclusions: The results provide some information regarding GMed recruitment during exercise, although there were some discrepancies in results between studies which may be due to factors related to EMG measurement and recording as well as the execution of the exercise. Extrapolation of results to symptomatic populations in a clinical setting islimited.

Psychiatric disorders such as schizophrenia and autism are characterised by cellular disorganisation and dysconnectivity across the brain and can be caused by mutations in genes that control neurodevelopmental processes. To examine how neurodevelopmental defects can affect brain function and behaviour, we have comprehensively investigated the consequences of mutation of one such gene, Semaphorin-6A, on cellular organisation, axonal projection patterns, behaviour and physiology in mice. These analyses reveal a spectrum of widespread but subtle anatomical defects in Sema6A mutants, notably in limbic and cortical cellular organisation, lamination and connectivity. These mutants display concomitant alterations in the electroencephalogram and hyper-exploratory behaviour, which are characteristic of models of psychosis and reversible by the antipsychotic clozapine. They also show altered social interaction and deficits in object recognition and working memory. Mice with mutations in Sema6A or the interacting genes may thus represent a highly informative model for how neurodevelopmental defects can lead to anatomical dysconnectivity, resulting, either directly or through reactive mechanisms, in dysfunction at the level of neuronal networks with associated behavioural phenotypes of relevance to psychiatric disorders. The biological data presented here also make these genes plausible candidates to explain human linkage findings for schizophrenia and autism.

A novel bromide salt of the antidepressant bupropion (bupropion HBr) has recently been developed and approved for use in the United States. Given previous use of bromides to treat seizures, and that the existing chloride salt of bupropion (HCl) can cause seizures, it is important to determine if the HBr salt may be less likely to cause seizures than the HCl salt. In the present animal studies this was evaluated by means of quantified electroencephalogram (EEG), observation, and the rotarod test in mice and rats. Both bupropion salts were tested at increasing equimolar doses administered intraperitoneally. The results in mice showed that bupropion HCl 125 mg/kg induced a significantly higher ten-fold increase in the mean number of cortical EEG seizures compared to bupropion HBr (7.50 +/- 2.56 vs 0.75 +/- 0.96; p = 0.045), but neither drug caused any brain injuries. In rats bupropion HBr 100 mg/kg induced single EEG seizure activity in the cortical and hippocampal (depth) electrodes and in significantly (p < 0.05) fewer rats (44%) compared to bupropion HCl, which induced 1 to 4 convulsions per rat in all rats (100%) dosed. The total duration of cortical seizures in bupropion HCl-treated rats was significantly longer than the corresponding values obtained in bupropion HBr-treated rats (424.6 seconds vs 124.5 seconds respectively, p < 0.05). Bupropion HCl consistently induced more severe convulsions at each dose level compared to bupropion HBr. Both treatments demonstrated a similar dose-dependent impairment of rotarod performance in mice. In conclusion, these findings suggest that bupropion HBr may have a significantly lower potential to induce seizures in mice and rats, particularly at higher doses, compared to bupropion HCl. Determination of this potential clinical advantage will require human studies. If confirmed by such studies, it is likely that this potential beneficial clinical benefit would be due to the presence of the bromide salt given the long history of the use of bromide to treat seizure disorders.