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Electrical kindling, repeated brain stimulation eventually resulting in seizures, is widely used as an animal model of epileptogenesis and epilepsy. However, the stimulation electrode used for electric kindling targets unknown neuronal populations and may introduce tissue damage and inflammation. Optogenetics can be used to circumvent these shortcomings by permitting millisecond control of activity in genetically defined neurons without gross injury or inflammation. Here we describe an easy step-by-step protocol for optogenetic kindling – optokindling – by which seizures are eventually elicited in initially healthy mice through repeated light stimulation of neurons expressing Channelrhodopsin-2 (ChR2). Chronic EEG recordings may be performed over large time scales to monitor activity while video camera monitoring may be used to assess the behavioral severity of seizures. In conclusion, with optokindling, neuroscientists can elucidate the circuit changes that underpin epilepsy while minimizing the contribution of confounding factors such as brain damage and inflammation.

De novo mutations causing dysfunction of the ATP1A3 gene, which encodes the α3 subunit of Na+/K+-ATPase pump expressed in neurons, result in alternating hemiplegia of childhood (AHC). AHC manifests as paroxysmal episodes of hemiplegia, dystonia, behavioral abnormalities, and seizures. The first aim of this study was to characterize a novel knock-in mouse model (Atp1a3E815K+/−, Matoub, Matb+/−) containing the E815K mutation of the Atp1a3 gene recognized as causing the most severe and second most common phenotype of AHC with increased morbidity and mortality as compared to other mutations. The second aim was to investigate the effects of flunarizine, currently the most effective drug used in AHC, to further validate our model and to help address a question with significant clinical implications that has not been addressed in prior studies. Specifically, many E815K patients have clinical decompensation and catastrophic regression after discontinuing flunarizine therapy; however, it is not known whether this is congruent with the natural course of the disease and is a result of withdrawal from an acute beneficial effect, withdrawal from a long-term protective effect or from a detrimental effect of prior flunarizine exposure. Our behavioral and neurophysiological testing demonstrated that Matb+/− mice express a phenotype that bears a strong resemblance to the E815K phenotype in AHC. In addition, these mice developed spontaneous seizures with high incidence of mortality and required fewer electrical stimulations to reach the kindled state as compared to wild-type littermates. Matb+/− mice treated acutely with flunarizine had reduction in hemiplegic attacks as compared with vehicle-treated mice. After withdrawal of flunarizine, Matb+/− mice that had received flunarizine did neither better nor worse, on behavioral tests, than those who had received vehicle. We conclude that: 1) Our mouse model containing the E815K mutation manifests clinical and neurophysiological features of the most severe form of AHC, 2) Flunarizine demonstrated acute anti-hemiplegic effects but not long-term beneficial or detrimental behavioral effects after it was stopped, and 3) The Matb+/− mouse model can be used to investigate the underlying pathophysiology of ATP1A3 dysfunction and the efficacy of potential treatments for AHC.

Abstract Background Current antiepileptic drugs are not able to prevent recurrent seizures in all patients. Orexins are excitatory hypothalamic neuropeptides that their receptors (Orx1R and Orx2R) are found almost in all major regions of the brain. Pentylenetetrazol (PTZ)-induced kindling is a known experimental model for epileptic seizures. The purpose of this study was to evaluate the effect of Orx2 receptor antagonist (TCS OX2 29) on seizures and anxiety of PTZ-kindled rats. Results Our results revealed that similar to valproate, administration of 7 µg/rat of TCS OX2 29 increased the latency period and decreased the duration time of 3rd and 4th stages of epileptiform seizures. Besides, it significantly decreased mean of seizure scores. However, TCS OX2 29 did not modulate anxiety induced by repeated PTZ administration. Conclusion This study showed that blockade of Orx2 receptor reduced seizure-related behaviors without any significant effect on PTZ-induced anxiety.

Background and Aim: Emotional disorders are prevalent in many epileptic patients. So, in this research, we have studied the efficacy of two treatment methods of seizure on anxiety-like behavior during kindling in adult male rat. Materials and Methods: 42 male rats were randomly divided into 6 groups: Control, Sham operation, saline-kindled and drug-kindled groups which have received saline or drug 15 minutes before kindling stimulations, and saline-kindled-LFS or drug-kindled-LFS group which have received saline or drug 15 minutes before kindling stimulations and LFS applied after termination of kindling stimulations. Anxiety-like behavior was assessed on the 6th day by using elevated plus maze and open field apparatus. Findings: kindling significantly increased open arms (OAs) entries percentage, OAs exploration percentage, increasing jumping from elevated plus maze (p

Introduction: The life quality of patients with epileptic seizures is highly affected by cognitive deficits. Low Frequency Stimulation (LFS) is a novel approach for the treatment of pharmacoresistant epilepsy. The main goal of this research is investigating the possible effect of LFS on seizure-induced cognitive dysfunction. Methods: To this end, the kindled animal were prepared via CA1 electrical stimulation in a semi-rapid way (12 stimulations/day). A group of animals were stimulated with LFS, 4 times at 30 s, 6 h, 24 h, and 30 h after the last kindling stimulation. Applied LFS was administered in 4 packages every 5 minutes. The packages were designed with 200 monophasic 200 monophasic square wave pulses of 0.1 ms duration at 1 Hz. The passive-avoidance test was conducted on all animals in order to measure the learning and memory behavior. Results: Hippocampal kindled rats showed deficits in learning and memory when passive avoidance test was performed. Application of LFS reversed the impairment in learning and memory behavior in kindled rats. At the same time, LFS markedly diminished kindling-induced neuronal loss and atrophy in the hippocampus. Conclusion: LFS may have some protection against seizure-induced cognitive damage in kindled rats.

• Complex movement representations take up more cortical area following seizures. • Complex movement representations overlap with other movement representations following seizures. • Reducing GABA-medicated inhibition also expands movement representations but does not result in overlap. • Reducing GABA-mediated inhibition results in novel but truncated movements. Alterations in the functional organization of motor cortex and interictal motor deficits are observed in people with epilepsy. While seizures in the rat lead to more cortical area devoted to simple cortical forelimb movement representations (motor maps) assessed using short-duration intracortical microstimulation (ICMS), the effect of seizures on complex movements derived with long-duration ICMS is unknown. Further, the relationship between motor map expression and motor impairment is not well understood. We used long-duration ICMS in the rat to test the hypothesis that repeated seizure activity (cortical kindling) increases the extent of overlapping cortical representation where multiple forelimb movements are evoked to stimulation. Cortical kindling (n = 7) significantly expanded (100%) forelimb motor maps characterized by a proportional increase in both complex and simple movement representation areas, and significantly increased (285%) overlapping forelimb representation compared to sham-kindled controls (n = 5). In a second experiment, motor maps were derived with long-duration ICMS under acute cortical application of bicuculline (n = 6) to reduce intracortical inhibition or saline control (n = 10). Bicuculline also significantly expanded forelimb motor maps (108%) but without increasing representational overlap. Moreover, expanded map areas in bicuculline rats evoked qualitatively distinct forelimb movements to long-duration, but not short-duration (n = 5), ICMS that were truncated. Our evidence indicates that motor map expansion following repeated experimental seizures is associated with reduced segregation between cortical movement representations that is not entirely due to reduced cortical inhibition but may contribute to interictal motor deficits in some individuals with epilepsy. [ABSTRACT FROM AUTHOR]

Introduction: The interaction between antiepileptic drugs and brain electrical stimulation is a potential therapy to control seizures in patients with pharmacoresistance to drugs. So, the present study aimed to design to determine the effect of a subeffective dose of sodium valproate combined with low-frequency electrical stimulation during kindling. Methods: One tripolar electrode was implanted stereotactically in the CA1 hippocampus of male Wistar rats. One week after surgery, the rats were kindled by electrical stimulation of hippocampus in a rapid manner (12 stimulations/day) for 6 days with sodium valproate alone or combined with low-frequency electrical stimulation (four packages contained 200 monophasic square wave pulses of 0.1-ms duration at 1 Hz, immediately after kindling stimulations). The duration of afterdischarge, maximum latency to stages 4 and 5, and the maximum duration of these stages were recorded by electromadule during kindling. Results: Application of sodium valproate with low-frequency electrical stimulation caused a reduction in cumulative afterdischarge duration. The maximum latency to the onset of stage 5 seizure increased after sodium valproate application alone, without having a significant effect on the fourth stage. Our findings showed reductions in the seizures duration and increasing in the latency times of both stages after the application of sodium valproate with low-frequency electrical stimulation. Conclusion: It seems that usage of sodium valproate with low-frequency electrical stimulation during kindling was more effective to suppress the epileptic activity than its administration alone and may have a critical role on the antiepileptic effects of sodium valproate. [ABSTRACT FROM AUTHOR]

• Cortical astrocyte activation was seen in PTZ-kindled mice. • Increase in extracellular matrix components was seen in PTZ-kindled mice. • Density of WFA-positive perineural nets increased in the somatosensory cortex of PTZ-kindled mice. • The expression of VGLUT1- and GAD67-positive synapses increased in many cortices of PTZ-kindled mice. Although epilepsy is one of the most common chronic neurological disorders with a prevalence of approximately 1.0 %, the underlying pathophysiology remains to be elucidated. Understanding the molecular and cellular mechanisms involved in the development of epilepsy is important for the development of appropriate therapeutic strategy. In this study, we investigated the effects of status epilepticus on astrocytes, microglia, and extracellular matrix (ECM) molecules in the somatosensory cortex and piriform cortex of mice. Activation of astrocytes was observed in many cortices except the retrosplenial granular cortex after pentylenetetrazol (PTZ)-induced kindling in mice. Activated astrocytes in the cortex were found in layers 1–3 but not in layers 4–6. In the somatosensory and piriform cortices, no change was observed in the number of parvalbumin (PV)-positive neurons and PV-positive neurons covered with perineuronal nets. However, the amount of ECM in the extracellular space increased. The expression of VGLUT1- and GAD67-positive synapses also increased. Thus, in the PTZ-kindling epilepsy mice model, an increase in the number of ECM molecules and activation of astrocytes were observed in the somatosensory cortex and piriform cortex. These results indicate that PTZ-induced seizures affect not only the hippocampus but also other cortical areas. Our study findings may help to develop new therapeutic approaches to prevent seizures or their sequelae. [ABSTRACT FROM AUTHOR]

Epileptogenesis is a dynamical process that involves synaptic plasticity changes such as synaptic reorganization of excitatory and inhibitory systems and axonal sprouting in the hippocampus, which is one of the most studied epileptogenic regions in the brain. However, the early events that trigger these changes are not understood well. We investigated short‐term and long‐term synaptic plasticity parameters and T‐type Ca2+ channel activity changes in the early phase of a rat kindling model. Chronic pentylenetetrazole (PTZ) application was used in order to induce the kindling process in rats. The recordings were obtained from hippocampal slices in the CA1 region at 25th day of PTZ application. Tetraethylammonium was used in order to induce long‐term potentiation and T‐type Ca2+ channel activity was assessed in the presence of mibefradil. We found that tetraethylammonium‐induced long‐term potentiation was not prevented by mibefradil in the kindling group in contrast to control group. We also found an increase in paired‐pulse ratios in the PTZ‐applied group. Our findings indicate an increase in the "T‐type Ca2+ channel component of LTP" in the kindling group, which may be an early mechanism in epileptogenesis. [ABSTRACT FROM AUTHOR]

There is increasing recognition that, in a high percentage of cases, bipolar disorder is a progressive illness. Multiple types of sensitization (or increased reactivity to repetition of the same stimulus) drive illness progression. One of the clearest is that of episode sensitization, where increased numbers of prior episodes are associated with: faster recurrences; more dysfunction; disability; social, educational, and employment deficits; suicide; medical comorbidities; cognitive dysfunction; and an increased incidence of dementia in old age. Repetition of stressors and bouts of substance abuse can also result in sensitization. Each type of sensitization appears to have an epigenetic basis, such that preventing sensitization should minimize the accumulation of adverse epigenetic chemical marks on DNA, histones, and microRNA. New data emphasize the importance of early, consistent intervention after an initial manic episode. The cognitive dysfunction associated with a first episode improves only if there are no further episode recurrences during the next year. A randomized study has also shown that comprehensive multimodal prophylactic intervention for 2 years leads to improvements in illness course extending over a total of 6 years. Intensive treatment of the earliest stages of bipolar disorder can thus exert lasting positive effects on the course of illness. [ABSTRACT FROM AUTHOR]

Genetic Absence Epilepsy Rats from Strasbourg (GAERS) is a well-known animal model of absence epilepsy and they are resistant to electrical kindling stimulations. The present study aimed to examine possible differences in gamma-aminobutyric acid (GABA) levels and synapse counts in the substantia nigra pars reticulata anterior (SNRa) and posterior (SNRp) regions between GAERS and Wistar rats receiving kindling stimulations. Animals in the kindling group either received six stimulations in the amygdala and had grade 2 seizures or they were kindled, having grade five seizures. Rats were decapitated one hour after the last stimulation. SNR regions were obtained after vibratome sectioning of the brain tissue. GABA immunoreactivity was detected by immunogold method and synapses were counted. Sections were observed by transmission electron microscope and analyzed by Image J program. GABA density in the SNRa region of fully kindled GAERS and Wistar groups increased significantly compared to that of their corresponding grade 2 groups. The number of synapses increased significantly in kindled and grade 2 GAERS groups, compared to kindled and grade 2 Wistar groups, respectively, in the SNRa region. GABA density in the SNRp region of kindled GAERS group increased significantly compared to that of GAERS grade 2 group. In the SNRp region, both kindled and grade 2 GAERS groups were found to have increased number of synapses compared to that of GAERS control group. We concluded that both SNRa and SNRp regions may be important in modulating resistance of GAERS to kindling stimulations. [ABSTRACT FROM AUTHOR]

Background: Epilepsy is a chronic, complex, unprovoked, and recurrent disorder of the nervous system that affected several people worldwide. Phyllanthus amarus (PA) has been documented to have neuroprotective potential.Aim: To evaluate the potential of standardized extract of PA and its possible mechanism of action against the Pentylenetetrazol (PTZ)-induced convulsion and kindling associated post-ictal depression in experimental mice.Materials and Methods: Phyllathin was isolated from methanolic extract of PA and well-characterized using HPTLC, ESI-MS/MS, and LC/MS. Phyllathin containing a standardized extract of PA (50, 100, and 200 mg/kg) was administered in convulsed and kindled mice, followed by an assessment of various parameters.Results: The spectral analysis confirmed the molecular formula and weight of phyllanthin as C24H34O6 and 418.2342 Da. PA (100 and 200 mg/kg) significantly ameliorated PTZ-induced (p < 0.05) duration, onset of tonic-clonic convulsion, and mortality in mice. It also significantly attenuated (p < 0.05) PTZ-induced kindling in mice. Alteration in brain GABA, dopamine, and glutamate, Na+K+ATPase, Ca+2-ATPase activities, and oxido-nitrosative stress in kindled mice was significantly restored (p < 0.05) by PA treatment. It also significantly (p < 0.05) down-regulated brain mRNA expressions of NF-κB, TNF-α, IL-1β, COX-2, and TLR-4. Histological aberrations induced by PTZ in the brain of a kindled rat was significantly (p < 0.05) ameliorated by PA.Conclusion: Phyllanthin containing a standardized extract of PA exerts its antiepileptic potential via balancing excitatory (glutamate) and inhibitory (GABA) brain monoamines, voltage-gated ion channels (Na+K+/Ca+2-ATPase) and inhibition of NF-κB/TLR-4 pathway to ameliorate neuroinflammation (TNF-α, IL-1β, and COX-2) in experimental mice. [ABSTRACT FROM AUTHOR]

The transient receptor potential vanilloid-1 (TRPV1) receptor has been implicated in the development of epileptic seizures. We examined the effect of the TRPV1 agonist capsaicin on epileptic seizures, neuronal injury and oxidative stress in a model of status epilepticus induced in the rat by intraperitoneal (i.p.) injections of pentylenetetrazole (PTZ). Capsaicin was i.p. given at 1 or 2 mg/kg, 30 min before the first PTZ injection. Other groups were i.p. treated with the vehicle or the anti-epileptic drug phenytoin (30 mg/kg) alone or co-administered with capsaicin at 2 mg/kg. Brain levels of malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide, and paraoxonase-1 (PON-1) activity, seizure scores, latency time and PTZ dose required to reach status epilepticus were determined. Histopathological assessment of neuronal damage was done. Results showed that brain MDA decreased by treatment with capsaicin, phenytoin or capsaicin/phenytoin. Nitric oxide decreased by capsaicin or capsaicin/phenytoin. GSH and PON-1 activity increased after capsaicin, phenytoin or capsaicin/phenytoin. Mean total seizure score decreased by 48.8% and 66.3% by capsaicin compared with 78.7% for phenytoin and 69.8% for capsaicin/phenytoin treatment. Only phenytoin increased the latency (115.7%) and threshold dose of PTZ (78.3%). Capsaicin did not decrease the anti-convulsive effect of phenytoin but prevented the phenytoin-induced increase in latency time and threshold dose. Neuronal damage decreased by phenytoin or capsaicin at 2 mg/kg but almost completely prevented by capsaicin/phenytoin. Thus in this model of status epilepticus, capsaicin decreased brain oxidative stress, the severity of seizures and neuronal injury and its co-administration with phenytoin afforded neuronal protection. [ABSTRACT FROM AUTHOR]

Introduction: In this study, the role of A1 adenosine receptors in improving the effect of Low- Frequency Electrical Stimulation (LFS) on seizure-induced hyperexcitability of hippocampal CA1 pyramidal neurons was investigated. Methods: A semi-rapid hippocampal kindling model was used to induce seizures in male Wistar rats. Examination of the electrophysiological properties of CA1 pyramidal neurons of the hippocampus using whole-cell patch-clamp recording 48 h after the last kindling stimulation revealed that the application of LFS as two packages of stimulations at a time interval of 6 h for two consecutive days could significantly restore the excitability CA1 pyramidal neurons evidenced by a decreased in the of the number of evoked action potentials and enhancement of amplitude, maximum rise slope and decay slope of the first evoked action potential, rheobase, utilization time, adaptation index, first-spike latency, and post-AHP amplitude. Selective locked of A1 receptors by the administration of 8-Cyclopentyl-1,3-dimethylxanthine (1 µM, 1 µl, i.c.v.) before applying each LFS package, significantly reduced LFS effectiveness in recovering these parameters. Results: On the other hand, selective activation of A1 receptors by an injection of N6- cyclohexyladenosine (10 µM, 1 µl, i.c.v.), instead of LFS application, could imitate LFS function in improving these parameters. Conclusion: It is suggested that LFS exerts its efficacy on reducing the neuronal excitability, partially by activating the adenosine system and activating its A1 receptors. [ABSTRACT FROM AUTHOR]

Methylene blue (MethyB) was shown to protect against different brain pathologies. In this study, the effect of acute administration of MethyB on epileptic seizures, brain oxidative stress, and neuronal injury induced in rats by pentylenetetrazole (PTZ) was studied. Rats received repeated intraperitoneal (i.p.) injections of PTZ until the development of status epilepticus and were i.p. treated once with MethyB at doses of 50 or 100 mg/kg, 30 min prior to the first PTZ injection. Results indicated that compared with the PTZ control group, the administration of MethyB at 50 and 100 mg/kg decreased the mean seizure score over the study period by 48.8% and 55.1%, respectively. The development of myoclonic jerks and generalized tonic-clonic seizures was inhibited by 90.0–85.0% and 45.4–56.3%, respectively, compared with the PTZ control group. The mean latency to develop status epilepticus increased by 43.1% after treatment with MethyB at 100 mg/kg. MethyB had no significant effect on the mean threshold dose of PTZ required to reach status epilepticus. MethyB showed inhibitory effects on the increase in brain lipid peroxidation (malondialdehyde), and nitric oxide induced PTZ by 16.7–24.0% and 25.2–32.6%, respectively. Meanwhile, the decrease in reduced glutathione and paraoxonase-1 (PON-1) activity and the increase in nuclear factor-kappa B (NF-κB) in the brain of PTZ-treated rats were attenuated by MethyB. Brain acetylcholinesterase (AChE) concentration decreased by PTZ and showed further decrements after treatment with either dose of MethyB. PTZ caused neuronal atrophy in the hippocampus and cerebral cortex and decreased neuronal size and number in the substantia nigra. These pathological changes were prevented by MethyB given at 100 mg/kg. These data indicate that treatment with MethyB inhibits the PTZ-induced seizures in rats and increases the latency to develop status epilepticus. In addition, MethyB decreases brain oxidative stress and protects against neuronal atrophy in this experimental model of generalized epilepsy. [ABSTRACT FROM AUTHOR]

Background: Recent studies have reported observing antioxidant, anti-inflammatory, and anti-aging properties of α-L-Guluronic acid (G2013) in animal and human studies. It has been theorized that the antioxidant and anti-inflammatory properties of G2013 might be beneficial in epilepsy treatment. Objective: We sought to determine G2013's effects on epileptic activity in a kindling-induced animal model. Methods: Thirty rats were randomly divided evenly into three groups (10 rats in each group): 1) the G2013 group, which was treated with daily injections of G2013 for five days prior to the start of the study; during the 14-day study period, the G2013 rats were given single, daily injections of G2013 that preceded single daily injections of pentylenetetrazole (PTZ), a compound used to induce seizures; 2) the Normal group, which only received injections of saline during the 14-day study, with no seizure induction; and 3) the Control group, which received PTZ injections alone (for seizure induction) for the 14-day study period. The latency between seizure stages and duration of seizures in the G2013 and Control groups were measured using a 5-stage seizure severity scale. Brain samples were taken from all three groups and analyzed histopathologically for parenchymal and meningeal inflammatory cell infiltration. Additionally, the brain samples were analyzed to determine gene expression levels of interleukin-1-beta (IL-1β), IL-6, IL-10), tumor necrosis factor (TNF), chemokine (C-C motif) ligand-2 (CCL2), cyclooxygenase-2 (COX-2), and interferon-gamma (IFN-γ). Results: The G2013 group demonstrated lower latency between Stages 2 and 5 seizures, with significantly longer mean duration of Stage 5 seizures, compared to the Control group. No significant differences were observed between the three groups histopathologically nor were there any observed differences in gene expression levels. Conclusion: Our results demonstrated a greater predisposition to PTZ-induced seizures in the rats who received G2013 and PTZ compared to rats who received PTZ alone, suggesting that G2013's epileptogenic property overshadows its anti-inflammatory effects when applied to a kindled animal model of study. [ABSTRACT FROM AUTHOR]

Background and Objectives Nowadays, the application of Low Frequency Stimulations (LFS) has been considered as an alternative treatment in drug-resistant epileptic patients. So, the aim of this study was to determine the co- administration effects of LFS and carbamazepine (CBZ) during epileptogenesis in dorsal hippocampus using electrical Kindling method on seizure scales in adult male rats. Materials and Methods: In this experimental study, 56 adult male wistar rats were randomly divided into 8 equal groups including: Kindled (KND), KLFS, MCK, CBZ20K, CBZ40K, CBZ20KLFS, CBZ40KLFS, and MCKLFS. Animals in the Kindled group received daily stimulation of kindling. In the KLFS group, LFS were applied daily after the termination of kindling stimulation. In the MCK group, before induction of kindling stimulation, the amount of 0.2 ml of %0.5 methyl cellulose was injected, and CBZ20K and CBZ40K groups received CBZ20 and 40mg / kg. In the CBZ20KLFS, CBZ40KLFS, and MCKLFS groups in addition to receiving drug or solvent, LFS was applied at the end of kindling stimulation. Animal behavioral seizure scales (seizure severity, afterdischarge duration and seizure duration) were recorded. Finally, data were analyzed using one-way ANOVA followed by Tukey's post hoc test. Results: The results showed that the combination therapy of LFS and the effective and ineffective amounts of CBZ significantly reduced the seizure scales in CBZ20KLFS and CBZ40KLFS groups compared with the other experimental groups (p=0.035). Conclusion: It seems that combination therapy of CBZ and LFS is an appropriate method to reduce seizure scales during kindling in rats. [ABSTRACT FROM AUTHOR]

Electrical kindling, repeated brain stimulation eventually resulting in seizures, is widely used as an animal model of epileptogenesis and epilepsy. However, the stimulation electrode used for electric kindling targets unknown neuronal populations and may introduce tissue damage and inflammation. Optogenetics can be used to circumvent these shortcomings by permitting millisecond control of activity in genetically defined neurons without gross injury or inflammation. Here we describe an easy step-by-step protocol for optogenetic kindling – optokindling – by which seizures are eventually elicited in initially healthy mice through repeated light stimulation of neurons expressing Channelrhodopsin-2 (ChR2). Chronic EEG recordings may be performed over large time scales to monitor activity while video camera monitoring may be used to assess the behavioral severity of seizures. In conclusion, with optokindling, neuroscientists can elucidate the circuit changes that underpin epilepsy while minimizing the contribution of confounding factors such as brain damage and inflammation. [ABSTRACT FROM AUTHOR]

OBJECTIVE: This study aimed to investigate the effects of ?-butyrolactone (GBL), a prodrug of gamma-Hydroxybutyric acid -induced absence seizures on the development of kindling in Wistar rats. METHODS: Three groups of adult male Wistar rats under anesthesia were implanted with bilateral cortical recording electrodes for the GBL group (GBL) and/or bipolar stimulation electrodes into the right basolateral amygdala for the Kindling group (KI) alone and Kindling plus GBL group (GBL+KI). Rats in the KI and GBL+KI groups were stimulated twice daily at the afterdischarge threshold until they reached Racine's stage 5 seizure state. The animals in the GBL + group had an i.p injection of GBL 20 minutes before each electrical stimulation, and the effects of GBL-induced seizures on the development of kindling were investigated. The animals in the GBL group were injected GBL twice daily i.p. for 15 days without receiving any electrical stimulation. RESULTS: The KI animals reached stage 5 seizure stage at 12th stimulations, whereas the GBL+KI rats reached at 27th stimulations. The mean numbers of stimulations needed for the development of the first stage 3, 4, or 5 generalized seizures were significantly higher in the GBL+KI group than the KI group. CONCLUSION: The resistance to amygdala kindling in the GBL model can be modulated by the absence seizure mechanism alone, without the intervention of an abnormal genetic background. [ABSTRACT FROM AUTHOR]

The incidence of seizures increases with old age. Stroke, dementia and brain tumors are recognized risk factors for new-onset seizures in the aging populations and the incidence of these conditions also increased with age. Whether aging is associated with higher seizure susceptibility in the absence of the above pathologies remains unclear. We used classic kindling to explore this issue as the kindling model is highly reproducible and allows close monitoring of electrographic and motor seizure activities in individual animals. We kindled male young and aging mice (C57BL/6 strain, 2–3 and 18–22 months of age) via daily hippocampal CA3 stimulation and monitored seizure activity via video and electroencephalographic recordings. The aging mice needed fewer stimuli to evoke stage-5 motor seizures and exhibited longer hippocampal afterdischarges and more frequent hippocampal spikes relative to the young mice, but afterdischarge thresholds and cumulative afterdischarge durations to stage 5 motor seizures were not different between the two age groups. While hippocampal injury and structural alterations at cellular and micro-circuitry levels remain to be examined in the kindled mice, our present observations suggest that susceptibility to hippocampal CA3 kindling seizures is increased with aging in male C57 black mice.

Chemical kindling is broadly used experimental model to investigate novel treatments on the process of epileptogenesis and coexisting behavioral comorbidities. The current study aimed to investigate the low dose perampanel (PER) (0.125 and 0.5 mg/kg) and pregabalin (PG) (15 mg/kg) as standalone treatments and in combination on kindling-induced seizure progression with concurrent electroencephalographic alterations. Mice were subjected to pentylenetetrazole (PTZ)-induced kindling followed by neurobehavioral assessment for anxiety-like activity and cognitive deficit through behavioral experiments. The monotherapy with PER at 0.5 mg/kg and PG at 15 mg/kg delayed the kindling process but PRP+PG yielded pronounced benefits and hindered the development of seizures of higher severity. PER+PG combination relieved the animals from anxiety-like behavior in various employed anxiogenic tests. Furthermore, the kindling-associated cognitive deficit was protected by PER+PG combination as increased alteration behavior, discrimination index and latencies to enter the dark zone were noted in y-maze, object recognition and passive avoidance tests, respectively while shorter escape latencies were noted in water maze. The brain samples of kindled mice had elevated malondialdehyde and reduced catalase, superoxide dismutase and glutathione peroxidase enzymes while treatment with PER and PG combination shielded the mice from heightened kindling-associated oxidative stress. Overall, the findings of the present study illustrate that concurrent administration of PER and PG effectively hindered the process of epileptogenesis by protecting neuronal excitability and brain oxidative stress. The results predict the dominance of PER and PG combination over monotherapy which might serve as an effective novel combination to combat drug resistance and behavioral disorders in epileptic patients. [Display omitted] • Impact of low doses of perampanel and pregabalin was evaluated in PTZ-kindled mice. • Polypharmacy prevented seizure progression and electrographic changes more effectively. • Combination protected from kindling-associated anxiety, cognitive deficit and depression. • Permapanel and pregabalin protected from kindling-induced brain oxidative stress. [ABSTRACT FROM AUTHOR]

Oxidative status is important in reproductive performance and using two natural antioxidants is more beneficial than one in nulliparous rabbits. The goal, effect of vitamin E (VitE), D‐limonene (DL), and VitE+DL on maternal LBW (MLBW), conception (CR), pregnancy (PR), and kindling rates (KR), gestation length (GL), total litter size at birth (TLSB) and weaning (TLSW), live kits at birth (LKB) and weaning (LKW), dead kits at birth (DKB) and weaning (DKW), kits mortality rate at weaning (KMRW), Kit weight at birth (KWB) and weaning (KWW), total kit weight at birth (TKWB) and weaning (TKWW), and concentrations of progesterone (P4) and Malondialdehyde (MDA), during first two pregnancies. A total of 24 healthy female WNZ rabbits were randomly selected and assigned into four groups (6/each). Control (animals injected with 1.0 mL propylene glycol), VitE (60 mg IM injection/animal, 2X/week pre-mating and 3X post-mating until mid-pregnancy, DL (20 mg IM injection/animal, 2X/week pre-mating and 1X at mating, and VitE+DL (IM injection/animal with the same doses and times applied in VitE and DL groups. All animals were treated during 1st pregnancy only. The results confirmed that animals treated with VitE+DL gained significant maternal LBW in 1st pregnancy, reduced dead kit number at birth and kit mortality rate at weaning, increased live kits and total kit weight at birth and weaning in the two pregnancies, and also increased significantly kit weight at birth and weaning in the treatments than controls in the two pregnancies, and DL was greater in 1st pregnancy. Progesterone concentrations in mid-pregnancy rose significantly in VitE+DL during 1st pregnancy and DL in 2nd pregnancy. Malondialdehyde concentrations dropped significantly in VitE and VitE+DL in mid-pregnancy in the two pregnancies. Eventually, the integration of VitE and DL displayed their unique properties for improving productive and reproductive performance in nulliparous rabbits. • Vitamin E, d-limonene. • P4, MDA. • Maiden female rabbit. • Reproductive performance. [ABSTRACT FROM AUTHOR]

The relevance of secondary epileptogenesis for human epilepsy remains a controversial subject decades after it was first described in animal models. Whether or not a previously normal brain region can become independently epileptogenic through a kindling-like process has not, and cannot, be definitely proven in humans. Rather than reliance on direct experimental evidence, attempts to answering this question must depend on observational data. In this review, observations based largely upon contemporary surgical series will advance the case for secondary epileptogenesis in humans. As will be argued, hypothalamic hamartoma-related epilepsy provides the strongest case for this process; all the stages of secondary epileptogenesis can be observed. Hippocampal sclerosis (HS) is another pathology where the question of secondary epileptogenesis frequently arises, and observations from bitemporal and dual pathology series are explored. The verdict here is far more difficult to reach, in large part because of the scarcity of longitudinal cohorts; moreover, recent experimental data have challenged the claim that HS is acquired consequent to recurrent seizures. Synaptic plasticity more than seizure-induced neuronal injury is the likely mechanism of secondary epileptogenesis. Postoperative running-down phenomenon provides the best evidence that a kindling-like process occurs in some patients, evidenced by its reversal. Finally, a network perspective of secondary epileptogenesis is considered, as well as the possible role for subcortical surgical interventions. • Hypothalamic hamartoma-related epilepsy provides the strongest case for secondary epileptogenesis in humans. • Hippocampal sclerosis and related temporal lobe epilepsies may progress by kindling-like mechanisms in some patients. • The running-down phenomenon is not rare and evidences secondary epileptogenesis by its resolution. [ABSTRACT FROM AUTHOR]

Metabolic intervention strategy of epilepsy treatment has been gaining broader attention due to accumulated evidence that hypometabolism, manifested in humans as reduced brain glucose consumption, is a principal factor in acquired epilepsy. Therefore, targeting deficient energy metabolism may be an effective approach for treating epilepsy. To confront this pathology we utilized pyruvate, which besides being an anaplerotic mitochondrial fuel possesses a unique set of neuroprotective properties as it: (i) is a potent reactive oxygen species scavenger; (ii) abates overactivation of Poly [ADP-ribose] polymerase 1 (PARP-1); (iii) facilitates glutamate efflux from the brain; (iv) augments brain glycogen stores; (v) is anti-inflammatory; (vi) prevents neuronal hyperexcitability; and (vii) normalizes the cytosolic redox state. In vivo, chronic oral pyruvate administration completely abolished established epileptic phenotypes in three accepted and fundamentally different rodent acquired epilepsy models. Our study reports metabolic correction by pyruvate as a potentially highly effective treatment of acquired epilepsies.

How a seizure spreads from a focal onset zone to other regions of the brain is not well understood, and animal studies suggest that there is a genetic influence. To understand how genetic factors may influence seizure spread, we examined whether the kindling resistance of WAG/Rij rats, which are slow to develop kindled motor seizures, is independent of the site of seizure induction and thus a global phenomenon, or whether it is circuit specific.We compared the kindling rates (number of stimulations to induce kindled motor seizures) of WAG/Rij rats to the rates of kindling in Sprague Dawley rats. Both groups underwent a standard hippocampal kindling protocol and a separate group was kindled from the medial dorsal nucleus of the thalamus, a site that has been previously demonstrated to result in the very rapid development of motor seizures. To examine whether there were differences in the interaction in a circuit involved with the motor seizures, evoked responses were obtained from the prefrontal cortex following stimulation of the subiculum or medial dorsal thalamic nucleus.The WAG/Rij rats once again demonstrated resistance to kindling in the hippocampus, but both strains kindled rapidly from the medial dorsal nucleus. In the WAG/Rij rats there was also a reduction in the duration of the afterdischarge in the frontal cortex during hippocampal stimulation, but there was no reduction during thalamic kindling. The prefrontal cortex evoked responses were reduced following stimulation of the subiculum in the WAG/Rij rats, but the evoked responses to thalamic stimulation were the same in both strains.These findings suggest that there are genetic influences in the strength of the input from the subiculum to the prefrontal cortex in WAG/Rij rats that could explain the resistance to limbic kindling because of reduced excitatory drive onto a key target region.

Abstract Background Evidence suggests that alcohol use and smoking are negatively associated with mood in bipolar disorders (BD). It is unknown if this relationship is moderated by the number of previous mood episodes. Therefore, this paper aims to examine whether the number of previous mood episodes moderates the relationship between alcohol use and smoking, and mood. Method This study assessed the outcomes of 108 outpatients with BD I and II in a prospective observational cohort study. For 1 year, subjects daily registered mood symptoms and substance use with the prospective Life Chart Method. The relationship between the average daily consumption of alcohol and tobacco units in the whole year and mood were examined by multiple linear regression analyses. Number of previous mood episodes, grouped into its quartiles, was added as effect moderator. Outcome was the number of depressive, hypomanic and manic days in that year. Results The number of depressive days in a year increased by 4% (adjusted β per unit tobacco = 1.040; 95% CI 1.003–1.079; p = 0.033) per unit increase in average daily tobacco consumption in that same year. Interaction analyses showed that in those subjects with less than 7 previous mood episodes, the number of manic and hypomanic days increased by 100.3% per unit increase in alcohol consumption (adjusted β per unit alcohol = 2.003; 95% CI 1.225–3.274; p = 0.006). In those with 7 to 13 previous mood episodes, the number of manic and hypomanic days decreased by 28.7% per unit increase in alcohol consumption (adjusted β per unit alcohol = 0.713; 95% CI 0.539–0.944; p = 0.019); and in subjects with 14 to 44 previous mood episodes, the number of manic and hypomanic days decreased by 7.2% per unit increase in tobacco consumption (adjusted β per unit tobacco = 0.928; 95% CI 0.871–0.989; p = 0.021). Conclusions The number of previous mood episodes moderates the relationship between alcohol use and smoking and mood; and smoking is adversely associated with the number of depressive days.

Abstract Background Antiaris toxicaria has previously shown anticonvulsant activity in acute animal models of epilepsy. The aqueous extract (AAE) was further investigated for activity in kindling with pentylenetetrazole and administration of pilocarpine and kainic acid which mimic temporal lobe epilepsy in various animal species. Results ICR mice and Sprague–Dawley rats were pre-treated with AAE (200–800 mg kg−1) and convulsive episodes induced using pentylenetetrazole, pilocarpine and kainic acid. The potential of AAE to prevent or delay onset and alter duration of seizures were measured. In addition, damage to hippocampal cells was assessed in kainic acid-induced status epilepticus test. 800 mg kg−1 of the extract suppressed the kindled seizure significantly (P

Context: Eclipta alba (Linn) Hassk. (Asteraceae) has been reported to be a nerve tonic and has been used to treat epilepsy in folk medicine. Objective: The present study isolates and characterizes luteolin from E. alba and evaluates its antiepileptic potential in chemically induced acute and chronic models in mice. Materials and methods: The methanol extract (16.85% w/w) of E. alba leaves was subjected to fractionation for isolation of luteolin. In acute pentylenetetrazole (PTZ) model, luteolin (5, 10, 20 mg/kg, i.p.) was administered 30 min prior to PTZ injection (100 mg/kg) in Swiss albino mice. Kindling was induced by chronic administration of PTZ (35 mg/kg) on every alternate day (48 days). Luteolin was investigated on the course of kindling development and oxidative stress markers [reduced glutathione (GSH) and malondialdehyde (MDA)] in kindled mice. Results: Single-dose pretreatment with luteolin (10 and 20 mg/kg, i.p.) was found to be effective in an acute PTZ model (100% protection from mortality) and it did not exhibit any effect on motor coordination at the same doses. PTZ-induced kindling was significantly (p

Epilepsy is a major neurological disorder characterized by repeated seizures afflicting 1% of the global population. The emergence of seizures is associated with several comorbidities and severely decreases the quality of life of patients. Unfortunately, around 30% of patients do not respond to first-line treatment using anti-seizure drugs (ASDs). Furthermore, it is still unclear how seizures arise in the healthy brain. Therefore, it is critical to have well developed models where a causal understanding of epilepsy can be investigated. While the development of seizures has been studied in several animal models, using chemical or electrical induction, deciphering the results of such studies has been difficult due to the uncertainty of the cell population being targeted as well as potential confounds such as brain damage from the procedure itself. Here we describe novel approaches using combinations of optical and genetic methods for studying epileptogenesis. These approaches can circumvent some shortcomings associated with the classical animal models and may thus increase the likelihood of developing new treatment options.

Temporal lobe epilepsy is the most common and often drug-resistant type of epilepsy in the adult and aging populations and has great diversity in etiology, electro-clinical manifestations, and comorbidities. Kindling through repeated brief stimulation of limbic structures is a commonly used model of temporal lobe epilepsy. Particularly, extended kindling can induce spontaneous recurrent seizures in several animal species. However, kindling studies in middle-aged, aging, or aged animals remain scarce, and currently, little is known about kindling-induced behavioral changes in middle-aged/aging animals. We therefore attempted to provide more information in this area using a mouse model of extended hippocampal kindling. We conducted experiments in middle-aged mice (C57BL/6, male, 12–14 months of age) to model new-onset epilepsy in adult/aging populations. Mice experienced twice daily hippocampal stimulations or handling manipulations for 60–70 days and then underwent continuous electroencephalogram (EEG)-video monitoring to detect spontaneous recurrent seizures. Extended kindled mice consistently exhibited spontaneous recurrent seizures with mean incidences of 6–7 events per day, and these seizures featured EEG discharges and corresponding convulsions. The handling control mice showed neither seizure nor aberrant EEG activity. The two groups of mice underwent the Morris water maze test of spatial learning and memory 1–2 weeks after termination of the kindling stimulation or handling manipulation. During visible platform trials, the kindled mice took a longer distance and required more time than the control mice to find the platform. During hidden platform trials, the kindled mice showed no improvement over 5-day trials in finding the platform whereas the control mice improved significantly. During probe tests in which the hidden platform was removed, the kindled mice spent less time than the controls searching in the correct platform location. There were no significant differences between the kindled and control mice with respect to swim speed or total locomotor activity in an open-field test. Together, these observations indicate that the extended kindled mice with spontaneous recurrent seizures are impaired in spatial learning and memory as assessed by the Morris water maze test. We postulate that the extended hippocampal kindling in middle-aged mice may help explore epileptogenic mechanisms and comorbidities potentially relevant to new-onset temporal lobe epilepsy in adult and aging patients. Limitations and confounds of our present experiments are discussed to improve future examinations of epileptic comorbidities in extended kindled mice.

Approximately half of the people who suffer a major depressive episode for the first time experience recurrences, while the other half do not. Among the initially depressed, however, who will have recurrences remains a mystery, and cannot be forecasted with any statistical or clinical confidence. It is well documented, though, that highly stressful life events commonly precede first episodes of major depression, and that these experiences become progressively less common prior to recurrences. Determining the basis for this consistent empirical observation holds promise for discovering among the initially depressed who will become recurrent, helping to solve the current-day conundrum of recurrences. The present article has 2 overarching objectives. First, we evaluate stress sensitization, the prevailing theory for explaining the decreasing association of major life events with successive recurrences. Conceptual gaps, discrepancies, and misunderstandings are found for understanding the decreasing association, as well as for understanding recurrences. Research practices and logical errors also are exposed that compromise the integrity of the existing empirical record. Second, alternative theoretical accounts are proposed to explain the decreasing association of major life stress with recurrences. Two "dual pathway models" provide viable alternative explanations, fill in existing theoretical gaps, and supply additional advantages for understanding life stress, depression, and recurrences. Recommendations are made for evaluating the 3 respective models. In closing, limitations and remaining questions are discussed for discovering who, early in the lifetime course of major depression, is likely to have a lifetime of repeated recurrences. [ABSTRACT FROM AUTHOR]

Variation in the temporal patterns of electrical pulses in stimulation trains has opened a new field of opportunity for the treatment of neurological disorders, such as pharmacoresistant temporal lobe epilepsy. Whether this novel type of stimulation affects epileptogenesis remains to be investigated. The purpose of this study was to analyze the effects of temporally irregular deep brain stimulation on kindling-induced epileptogenesis in rats. Temporally irregular deep brain stimulation was delivered at different times with respect to the kindling stimulation. Behavioral and electrographic changes on kindling acquisition were compared with a control group and a temporally regular deep brain stimulation-treated group. The propagation of epileptiform activity was analyzed with wavelet cross-correlation analysis, and interictal epileptiform discharge ratios were obtained. Temporally irregular deep brain stimulation delivered in the epileptogenic focus during the interictal period shortened the daily afterdischarge duration, slowed the progression of seizure stages, diminished the generalized seizure duration and interfered with the propagation of epileptiform activity from the seizure onset zone to the ipsi- and contralateral motor cortex. We also found a negative correlation between seizure severity and interictal epileptiform discharges in rats stimulated with temporally irregular deep brain stimulation. These results provide evidence that temporally irregular deep brain stimulation interferes with the establishment of epilepsy by delaying epileptogenesis by almost twice as long in kindling animals. Thus, temporally irregular deep brain stimulation could be a preventive approach against epilepsy. • TiDBS applied at the epileptogenic focus delayed epileptogenesis in rats. • TiDBS delayed propagation from the epileptogenic focus to motor cortices. • IED's inversely correlate with seizure severity when TiDBS was applied. • TiDBS could be a preventive approach against epilepsy. [ABSTRACT FROM AUTHOR]

Increasing evidence demonstrates that electric stimulation has anticonvulsant effects. The present study was undertaken to investigate the effects of mild foot electrical stimulation (MFES) on the development of pentylenetetrazol (PTZ) kindling and compare its effectiveness with the more commonly used treatment, phenytoin. Kindling was induced in rats by repeated injections (every 24 h) of PTZ (37.5 mg/kg). The rats were subjected to either MFES (0.2 mA in intensity for a 160 ms duration with a 160 ms interval for 20 min) or phenytoin (30 mg/kg) before PTZ injections. Following this treatment, rats received MFES every other day for 10 days or 26 days after establishment of PTZ kindling. The data showed that MFES significantly inhibited development of chemical kindling induced by PTZ in rats (p = 0.001, as compared to PTZ-treated animals). This inhibitory effect is comparable with the effect of 30 mg/kg doses of phenytoin (P = 0.99, as compared to phenytoin group). However, 10 days or 26 days durations of MFES had no effect on established kindled seizures (P = 0.58 as compared to PTZ-treated animals). Our data demonstrate that although MFES significantly inhibited the development of chemical kindling, this experimental paradigm had no effect on established kindled seizures. [ABSTRACT FROM AUTHOR]

Temporal lobe epilepsy is the most common and often drug-resistant type of epilepsy in the adult and aging populations and has great diversity in etiology, electro-clinical manifestations, and comorbidities. Kindling through repeated brief stimulation of limbic structures is a commonly used model of temporal lobe epilepsy. Particularly, extended kindling can induce spontaneous recurrent seizures in several animal species. However, kindling studies in middle-aged, aging, or aged animals remain scarce, and currently, little is known about kindling-induced behavioral changes in middle-aged/aging animals. We therefore attempted to provide more information in this area using a mouse model of extended hippocampal kindling. We conducted experiments in middle-aged mice (C57BL/6, male, 12–14 months of age) to model new-onset epilepsy in adult/aging populations. Mice experienced twice daily hippocampal stimulations or handling manipulations for 60–70 days and then underwent continuous electroencephalogram (EEG)-video monitoring to detect spontaneous recurrent seizures. Extended kindled mice consistently exhibited spontaneous recurrent seizures with mean incidences of 6–7 events per day, and these seizures featured EEG discharges and corresponding convulsions. The handling control mice showed neither seizure nor aberrant EEG activity. The two groups of mice underwent the Morris water maze test of spatial learning and memory 1–2 weeks after termination of the kindling stimulation or handling manipulation. During visible platform trials, the kindled mice took a longer distance and required more time than the control mice to find the platform. During hidden platform trials, the kindled mice showed no improvement over 5-day trials in finding the platform whereas the control mice improved significantly. During probe tests in which the hidden platform was removed, the kindled mice spent less time than the controls searching in the correct platform location. There were no significant differences between the kindled and control mice with respect to swim speed or total locomotor activity in an open-field test. Together, these observations indicate that the extended kindled mice with spontaneous recurrent seizures are impaired in spatial learning and memory as assessed by the Morris water maze test. We postulate that the extended hippocampal kindling in middle-aged mice may help explore epileptogenic mechanisms and comorbidities potentially relevant to new-onset temporal lobe epilepsy in adult and aging patients. Limitations and confounds of our present experiments are discussed to improve future examinations of epileptic comorbidities in extended kindled mice. [ABSTRACT FROM AUTHOR]

Objective: The lamotrigine‐resistant amygdala kindling model uses repeated administration of a low dose of lamotrigine during the kindling process to produce resistance to lamotrigine, which also extends to some other antiseizure drugs (ASDs). This model of pharmacoresistant epilepsy has been incorporated into the testing scheme utilized by the Epilepsy Therapy Screening Program (ETSP). Although some ASDs have been evaluated in this model, a comprehensive evaluation of ASD prototypes has not been reported. Methods: Following depth electrode implantation and recovery, rats were exposed to lamotrigine (5 mg/kg, i.p.) prior to each stimulation during the kindling development process (~3 weeks). A test dose of lamotrigine was used to confirm that fully kindled rats were lamotrigine‐resistant. Efficacy (unambiguous protection against electrically elicited convulsive seizures) was defined as a Racine score < 3 in the absence of overt compound‐induced side effects. Various ASDs, comprising several mechanistic classes, were administered to fully kindled, lamotrigine‐resistant rats. Where possible, multiple doses of each drug were administered in order to obtain median effective dose (ED50) values. Results: Five sodium channel blockers tested (eslicarbazepine, lacosamide, lamotrigine, phenytoin, and rufinamide) were either not efficacious or effective only at doses that were not well‐tolerated in this model. In contrast, compounds targeting either GABA receptors (clobazam, clonazepam, phenobarbital) or GABA‐uptake proteins (tiagabine) produced dose‐dependent efficacy against convulsive seizures. Compounds acting to modulate Ca2+ channels show differential activity: Ethosuximide was not effective, whereas gabapentin was moderately efficacious. Ezogabine and valproate were also highly effective, whereas topiramate and levetiracetam were not effective at the doses tested. Significance: These results strengthen the conclusion that the lamotrigine‐resistant amygdala kindling model demonstrates pharmacoresistance to certain ASDs, including, but not limited to, sodium channel blockers, and supports the utility of the model for helping to identify compounds with potential efficacy against pharmacoresistant seizures. [ABSTRACT FROM AUTHOR]

The purpose of this study is to determine the activation of the extrinsic and intrinsic apoptotic pathways in the cerebellum of rats exposed to amygdaloid electrical kindling. Western blot analyses were carried out for caspase-8 and caspase-9, Bid, Bax, and Bcl-2 in the cerebellum and immunohistochemistry of Bid, Bax, cytochrome C, and VDAC (voltage-dependent anion channels) in the cerebellar cortex of Wistar male rats with 0, 15, and 45 kindling stimulations. In the experimental group of 45 stimuli, we observed an increase in protein activation of caspase-9 and truncated Bid and Bax, in addition to a decrease in expression of pro-caspase-8 and the anti-apoptotic protein Bcl-2, determined by Western blot. Moreover, we observed a cytosolic immunopositivity for cytochrome C and a mitochondrial immunolocalization for truncated Bid and Bax in the group of 45 stimuli. In this work, we found an increase of caspase-8, a cysteine-protease that can activate caspase-3 triggering extrinsic apoptosis by signaling of death receptors. However, it also can activate the intrinsic pathway releasing Bid, which performs mitochondrial translocation of Bax, inactivating Bcl-2 and allowing the release of cytochrome C through the opening of the mitochondrial permeability transition pore, promoting the activation of caspase-9 which activates caspase-3, the main executor caspase of apoptosis. Therefore, it is concluded that there is an activation of the intrinsic and extrinsic apoptotic pathways in the cerebellum of rats exposed to the kindling model. Apoptosis signaling pathways can be analyzed as an important developing object of research about the epileptic activity. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of Thymus vulgaris L. (TVL) on oxidative stress, motor coordination and learning/memory in acute and chronic epilepsy models in rats induced by Pentylenetetrazole (PTZ). To this end, 64 male Wistar-albino rats were randomly divided into eight groups with 8 rats each: (1) acute control (AC), (2) acute PTZ (APTZ), (3) acute PTZ + sodium valproate (APTZ+VPA), (4) acute PTZ + TVL (APTZ+TVL), (5) chronic control (CC), (6) PTZ kindling (PTZk), (7) PTZ kindling + VPA (PTZk+VPA) and (8) PTZ kindling + TVL (PTZk+TVL). Seizures were observed for 30 min after each PTZ injection and were scored. Acute PTZ-induced seizures were created by injecting a single convulsive dose of PTZ (60 mg/kg, ip) in acute groups. PTZ kindling was produced by injecting a subconvulsant dose of PTZ (35 mg/kg, ip) every other day, with 14 injections in total. No significant difference was found among the PTZk + VPA, PTZk, and PTZk + TVL groups with regard to seizure scores. No significant difference was found among all the 8 groups in the learning/memory tests conducted using the Morris Water Maze (MWM) test and the motor activity tests conducted using the rotarod test (P>0.05). The analysis of total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) indicated that the administration of PTZ decreased the antioxidant capacity and increased the oxidant capacity. Moreover, the TVL administration established the oxidant/antioxidant balance, particularly in the chronic groups. Further studies are needed to investigate whether high doses of TVL have an effect on PTZ-induced seizure scores. [ABSTRACT FROM AUTHOR]

Drug resistance is a major problem in the treatment of epilepsy. There is a critical need for new epilepsy models to evaluate antiepileptic compounds. Pentylenetetrazole- (PTZ) and pilocarpine-induced seizures are well-established models of human epilepsy. Generally, PTZ or pilocarpine has been used to produce seizures in experimental models. In this study, we explored the possibility of creating new epilepsy and seizure models by co-administration of PTZ and pilocarpine. The protocol was divided into three parts: A) Kindling experiments: the animals received PTZ or co-administration doses of PTZ and pilocarpine every other day for a period of 26 days. B) Seizure experiments, for induction of seizure, the animals received one dose of PTZ, pilocarpine or co-administration doses of PTZ and pilocarpine. C) Evaluation of antiepileptic drugs: the animals received phenytoin or sodium valproate 20 min before injection of PTZ, pilocarpine or co-administration doses of PTZ and pilocarpine. The co-administration of pilocarpine and PTZ could induce seizure, which has behavioral similarity between electrical and chemical kindling. Pilocarpine (50 mg/kg) + PTZ (37.5 mg/kg) was the appropriate dose for kindling induction. Animals with this dose reached the stage five seizures significantly faster than those with PTZ alone. Unlike the seizure induced by PTZ, or pilocarpine, induction of seizure by PTZ + pilocarpine was resistant to phenytoin and sodium valproate treatment. As compared to the PTZ model of kindling, this model visualized the seizure behavior better and had resistance to two most popular antiepileptic drugs. Our results indicated that co-administration of pilocarpine and PTZ could provide a new modified model of seizure and kindling resisting to phenytoin and sodium valproate. • Co-administration of pilocarpine and pentylenetetrazole could produce a new model of seizure and epilepsy. • Resistance to antiepileptic drugs can introduce this model as a suitable model for drug resistance researches. • This model shows better visualize of the seizure behavior and the more accurate measuring the seizure parameters. [ABSTRACT FROM AUTHOR]

Objective: The cystine/glutamate antiporter system xc− could represent a new target for antiepileptogenic treatments due to its crucial roles in glutamate homeostasis and neuroinflammation. To demonstrate this, we compared epilepsy development and seizure susceptibility in xCT knockout mice (xCT−/−) and in littermate controls (xCT+/+) in different chronic models of epilepsy. Methods: Mice were surgically implanted with electrodes in the basolateral amygdala and chronically stimulated to develop self‐sustained status epilepticus (SSSE); continuous video‐electroencephalography monitoring was performed for 28 days after SE and hippocampal histopathology was assessed. Corneal kindling was induced by twice daily electrical stimulation at 6 Hz and maintenance of the fully kindled state was evaluated. Next, messenger RNA (mRNA) and protein levels of xCT and of the proteins involved in the phosphoinositide 3‐kinase (PI3K)/Akt/glycogen synthase kinase 3β (GSK‐3β)/eukaryotic initiation factor 2α (eIF2α)/activating transcription factor 4 (ATF4) signaling pathway were measured at different time points during epileptogenesis in NMRI mice treated with pilocarpine. Finally, the anticonvulsant effect of sulfasalazine (SAS), a nonselective system xc− inhibitor, was assessed against 6 Hz‐evoked seizures in pilocarpine‐treated mice. Results: In the SSSE model, xCT−/− mice displayed a significant delayed epileptogenesis, a reduced number of spontaneous recurrent seizures, and less pronounced astrocytic and microglial activation. Moreover, xCT−/− mice showed reduced seizure severity during 6 Hz kindling development and a lower incidence of generalized seizures during the maintenance of the fully kindled state. In pilocarpine‐treated mice, protein levels of the PI3K/Akt/GSK‐3β/eIF2α/ATF4 pathway were increased during the chronic phase of the model, consistent with previous findings in the hippocampus of patients with epilepsy. Finally, repeated administration of SAS protected pilocarpine‐treated mice against acute 6 Hz seizure induction, in contrast to sham controls, in which system xc− is not activated. Significance: Inhibition of system xc− could be an attractive target for the development of new therapies with a potential for disease modification in epilepsy. [ABSTRACT FROM AUTHOR]

Glucose metabolism and serotonergic neurotransmission have been reported to play an important role in epileptogenesis. We therefore aimed to use neuroimaging to evaluate potential alterations in serotonin 5-HT 1A receptor and glucose metabolism during epileptogenesis in the rat electrical kindling model. To achieve this goal, we performed positron emission tomography (PET) imaging in a rat epileptogenesis model triggered by electrical stimulation of the hippocampus using 2-deoxy-2-[18F]fluoro-D-glucose (18F-FDG), a radiolabeled analog of glucose, and 2′-methoxyphenyl-(N -2′-pyridinyl)- p -18F-fluoro-benzamidoethylpiperazine (18F-MPPF), a radiolabeled 5-HT 1A receptor ligand, to evaluate brain metabolism and 5-HT 1A receptor functionality. Since the 5-HT 1A receptor is also highly expressed in astrocytes, glial fibrillary acidic protein (GFAP) immunofluorescence was performed to detect astrogliosis arising from the kindling procedure once the study was finalized. Lastly, in vitro 18F-MPPF autoradiography was performed to evaluate changes in 5HT 1A receptor expression. 18F-FDG PET showed reduction of glucose uptake in cortical structures, whereas 18F-MPPF PET revealed an enhancement of tracer binding potential (BP ND) in key areas rich in 5-HT 1A receptor involved in epilepsy, including septum, hippocampus and entorhinal cortex of kindled animals compared to controls. However, in vitro 5-HT 1A receptor autoradiography showed no changes in densitometric signal in any brain region, suggesting that the augmentation in BP ND found by PET could be caused by reduction of synaptic serotonin. Importantly, astroglial activation was detected in the hippocampus of kindled rats. Overall, electrical kindling induced hypometabolism, astrogliosis and serotonergic alterations in epilepsy-related regions. Furthermore, the present findings point to 5-HT 1A receptor as a valuable epileptogenesis biomarker candidate and a potential therapeutic target. • Hippocampal electrical kindling resulted in brain hypometabolism as assessed by 18F-FDG PET. • 18F-MPPF PET revealed a rise in 5-HT 1A BP ND in kindled rats but no change in densitometric signal was observed in vitro. • The in vivo and in vitro 18F-MPPF studies point to kindling-induced reduction of synaptic serotonin. • Contralateral alterations may reflect the positive transfer phenomenon in kindling. • Increased 18F-MPPF BP ND together with astrogliosis points to astroglial 5-HT 1A receptor as a potential therapeutic target. [ABSTRACT FROM AUTHOR]

Epilepsy is one of the most common neurological disorders that severely affect life quality of many people worldwide. Ion transport in the neuronal membrane, inhibitory–excitatory mechanisms, and regulatory modulator systems have been implicated in the pathogenesis of epilepsy. A bidirectional communication is proposed between brain and gut where the brain modulates the gastrointestinal tract, and the gut can affect brain function and behavior. The gut microbiome takes an important role in health and disease where dysbiosis is involved in several neurological disorders. Probiotics as living microorganisms are beneficial to humans and animals when adequately administered. In the present work, we evaluated the effect of a probiotic bacteria mixture on seizure activity, cognitive function, and gamma-aminobutyric acid (GABA), nitric oxide (NO), malondealdehyde (MDA), and total antioxidant capacity (TAC) level of the brain tissue in the pentylenetetrazole (PTZ)-induced kindled rats. The Racine score and performance in water maze were considered as indices of the epileptic severity and the spatial learning and memory, respectively. We found that the probiotic supplementation substantially reduces seizure severity so that almost no probiotic-treated animals showed full kindling. The oral bacteriotherapy partially improved the spatial learning and memory in the kindled rats. The intervention decreased NO and MDA and increased TAC concentration of the brain. The probiotic treatment also increased the inhibitory neurotransmitter GABA. Our findings are the first preclinical report to show positive effect of probiotic bacteria on seizure-induced neurological disorders. Further investigation is required to answer the questions raised about the probable mechanisms involved. • Epilepsy results of imbalance of excitation/inhibition & oxidant/antioxidant factors. • We asked if supporting gut flora by probiotics improves epileptic-related disorders. • Probiotic intake declined seizure level, restored impaired cognition and metabolites. • The first preclinical study proves that probiotics favorably affect brain disorders. [ABSTRACT FROM AUTHOR]

Objective: Harmaline and other beta-carbolines act as an inverse agonist for GABA-A receptors and cause central nervous system stimulation and anxiety; thus, it may act hypothetically as a potential seizure augmenter. To examine the hypothesis, the effect of harmaline during the seizures induced by amygdala kindling is investigated here. Methods: Seven groups of male rats were kindled by daily electrical stimulation of the amygdala. After being kindled, Groups I–III, respectively, received 5, 15 and 50 mg/kg harmaline through intraperitoneal injection. The rats in Groups IV and V received vehicle daily (1 ml/kg) and harmaline (5 mg/kg) daily through intraperitoneal injection. Groups VI and VII received artificial cerebrospinal fluid and harmaline (50 mM) through intraventricular injection, respectively. Results: In addition to significant increase of some seizure parameters in the fully kindled groups, harmaline significantly increased cumulative afterdischarge duration (P < 0.05) and decreased stage 1 latency (P < 0.01) in the acquisition groups (Groups V and VII). In Group VII, seizure duration showed a significant increase (P < 0.01) while stage 1 latency and stage 4 latency decreased significantly (P < 0.01). Discussion: According to the results, it is suggested that harmaline may increase neuronal activity and the production of high-frequency action potentials by stimulating NMDA receptors and inhibiting GABA receptors. Overall, drugs and plants containing harmaline may be harmful to epileptic-susceptible people during some traditionally and costume treatments, so these should be avoided. [ABSTRACT FROM AUTHOR]

Low-frequency stimulation has demonstrated promising seizure suppression in animal models of epilepsy, while the mechanism of the effect is still debated. Changes in intrinsic properties have been recognized as a prominent pathophysiologically relevant feature of numerous neurological disorders including epilepsy. Here, it was evaluated whether LFS can preserve the intrinsic neuronal electrophysiological properties in a rat model of epilepsy, focusing on the possible involvement of voltage-gated Ca2+ channels. The amygdala kindling model was induced by 3 s monophasic square wave pulses (50 Hz, 1 ms duration, 12times/day at 5 min intervals). Both LFS alone and kindled plus LFS (KLFS) groups received four packages of LFS (each consisting of 200 monophasic square pulses, 0.1 ms pulse duration at 1 Hz with the after discharge threshold intensity), which in KLFS rats was applied immediately after kindling induction. Whole-cell patch-clamp recordings were made in the presence of fast synaptic blockers 24 h after the last kindling stimulations or following kindling stimulations plus LFS application. In the KLFS group, both the rebound excitation and kindling-induced intrinsic hyperexcitability were decreased, associated with a regular intrinsic firing as indicated by a lower coefficient of variation. The amplitude of afterdepolarization (ADP) and its area under the curve were both decreased in the KLFS group compared to the kindled group. LFS prevented the increasing effect of kindling on Ca2+ currents in the KLFS group. Findings provided evidence for a novel form of epileptiform activity suppression by LFS in the presence of synaptic blockade possibly by decreasing Ca2+ currents. Unlabelled Image • Amygdala kindling alters intrinsic excitability of CA1 pyramidal neurons • Low-frequency stimulation (LFS) prevents the induction of neuronal intrinsic hyperexcitability by amygdala kindling. • Induction of amygdala kindling enhances Ca2 + channel current in CA1 pyramidal neurons • LFS prevented the increasing effect of epileptiform activity on Ca2+ currents. [ABSTRACT FROM AUTHOR]

Background and Objectives: Epilepsy is a chronic neurological disorder that requires long treatment with less side effects. Therefore, this study aimed to determine the effect of sodium valproate and electrical stimulation of the brain with low frequency (LFS) on the motor activity of male rat during hippocampus rapid kindling. Material and Methods: In this experimental study, 56 male adult rats were randomly divided to 8 groups: control, sham operation, saline-kindled and drug-kindled groups which received saline or drug 15 minutes before kindling stimulations and saline-kindled-LFS or drug-kindled-LFS group which received saline or drug 15 minutes before kindling stimulations and LFS after termination of kindling stimulations. Then animals motor activity was assessed on the 6th day by open field test and data were analyzed by one-way ANOVA and Tukey's post-test. Results: The open field results showed a significant increase in the number of motions (p =0.007) in the kindled group compared to the sham group. But these parameters showed no difference in saline-kindled-LFS group, drug-kindled and drug-kindled-LFS groups compared with the sham group (p˃0.05). Conclusion: It seems administration of sodium valproate and application of low-frequency electrical to hippocampus region can attenuate the kindling-induced hyperactivity in adult male rat. [ABSTRACT FROM AUTHOR]