Abstract Educational initiatives that address the gap between basic/preclinical and clinical practices are important to effectively translate basic science discoveries to benefit patients. The ILAE Neurobiology Commission conducted a pilot project aimed at exposing basic and preclinical scientists engaged in epilepsy research to general clinical issues pertaining to the diagnosis and care of people with epilepsy. This aim was addressed through a two‐week‐long, on‐site clinical training program for 50 basic scientists in 21 epilepsy centers across 18 countries in the six ILAE regions (with a maximum of 3 basic scientists per center). The learning objectives and the training module were discussed and defined by the project organizing committee, which consisted of Neurobiology Commission members and a team of epileptologists representing different geographical regions. The training activities were conducted at each epilepsy center under the local supervision of clinical tutors. Each basic scientist was exposed to 50.3 ± 23.3 (range 16–89) hours of intensive and dedicated clinical training, coordinated by 2–3 tutors per center, assisted by 6.8 ± 3.6 colleagues. A structured test consisting of 17 general clinical epilepsy questions was completed by the trainees before and after the training activity. The learning assessment was based on the comparison between responses to the exit and entry tests. After the on‐site clinical exposure, the proportion of correct answers increased to 87% compared to 61% in the entry test. Structured post‐training questionnaires demonstrated very high satisfaction of trainees and all involved tutors across the different aspects of the training module. This global pilot study demonstrated that on‐site attendance by basic scientists in specialized clinical settings up‐scaled their knowledge of clinical epileptology and facilitated networking with clinicians. Expansion of this pilot to further centers should be considered to understand how exposure to clinical practice affects research direction and quality of translational epilepsy research. Plain Language Summary Epilepsy research has long benefitted from collaboration between scientists and clinicians. Early exposure of researchers to people with epilepsy and their care teams may strengthen future impact. This pilot study tested a two‐week immersive experience where small teams of basic scientists shadowed clinicians during their work at hospitals around the world. Questionnaires showed high satisfaction among both groups. Results support expanding such training, with the backing of the International League Against epilepsy and aligned centers, to build understanding, interest, and long‐term commitment, ensuring bench research is informed by and translates to clinical practice and improved quality of life for patients.

AIMS:Absence seizures, characterized by spike-and-wave discharges (SWDs), are mediated by reciprocal thalamocortical interactions; however, the contribution of developing inhibitory networks to SWDs remains unclear. We investigated the developmental trajectory of inhibitory interneurons in Genetic Absence Epilepsy Rats from Strasbourg (GAERS) by analyzing their distribution across postnatal development in the somatosensory (S1) and motor (M1) cortices, the hippocampus, and striatum. METHODS:The neurodevelopmental trajectory of parvalbumin-positive (PV+) and somatostatin-positive (SST+) interneurons was quantified at three critical stages: postnatal day 14 (P14), when SWDs were not yet observed, P21 when immature SWDs appear, and adulthood (P90), when mature SWDs are established. Wistar rats served as controls. Brain sections were processed immunohistochemically to quantify interneuron density. RESULTS:PV+ interneuron density across S1 and M1 was significantly higher in GAERS at P14 than control. However, this difference was not maintained at P21 and adults. Conversely, SST+ interneurons exhibited a delayed increase in M1. GAERS displayed higher PV+ interneuron density in the dentate gyrus and CA1 at P14, whereas SST+ interneuron density remained unchanged across hippocampal subfields. Striatal PV+ and SST+ interneurons increased at later developmental stages, suggesting altered inhibition in basal ganglia. CONCLUSION:These findings demonstrate a temporally dynamic and region-specific reorganization of interneurons in GAERS that may underlie absence epileptogenesis.

Chemokine (CXC motif) ligand 8 (CXCL8) is a pro-inflammatory chemokine binding to CXC motif receptors 1/2 (CXCR1/2). Patients with temporal lobe epilepsy (TLE) exhibit increased serum CXCL8 levels. CXC motif ligand 1 (CXCL1), a murine ortholog of CXCL8, has been implicated in seizure generation and neuronal loss. This study evaluated the antiepileptogenic and antiseizure effects of reparixin in amygdaloid kindling rat model of TLE. Reparixin was administered during the kindling period for 14 days, and seizures were induced twice daily via electrical stimulation. To assess the antiseizure effects, reparixin was administered to fully kindled animals, and stimulations were performed 24 and 48 h later. Levetiracetam, a broad-spectrum antiseizure drug, was administered intraperitoneally (i.p.) as positive control 1 h before each stimulation. Reparixin delayed secondary seizure generalization during kindling. Reparixin reduced seizure severity and after-discharge duration in fully kindled animals at 24 h from treatment initiation. CXCR1/2 and protein kinase B pathway proteins exhibited no significant changes; reparixin reduced the phospho-extracellular signal-regulated kinase (pERK)/ERK ratio in the cortex and hippocampus. CXCL1 expression was significantly decreased in the cortex. Reparixin exhibited antiepileptogenic and partial antiseizure effects by modulating the CXCL1–CXCR1/2 axis and reducing ERK signaling. Already in clinical trials on respiratory diseases, reparixin could be repurposed for epilepsy therapy.

Introduction:Childhood Absence Epilepsy, a subtype of genetic generealised epilepsy, is characterised by sudden and brief episodes of impaired consciousness. The Leucine-rich glioma-inactivated protein 1 (LGI1) and N-methyl-D-aspartate receptor (NMDAR) are key proteins involved in regulating neuronal excitability. In conditions like anti-LGI1 encephalitis and anti-NMDAR encephalitis, autoantibodies target and disrupt these proteins, causing memory deficits, behavioural changes, sleep disturbances, and epileptic seizures. However, the roles of LGI1 and NMDAR dysfunction in the pathophysiology of absence of seizures remain unclear. This study aims to investigate the effects of LGI1 and NMDAR antibodies on absence seizures using two experimental models: Genetic Absence Epilepsy Rats from Strasbourg (GAERS) and a low-dose pentylenetetrazol (PTZ) model of absence seizures. Methods:IgG purified from the peripheral blood of healthy controls (HC IgG), and patients with anti-NMDAR, and anti-LGI1 encephalitis, was administered intracerebroventricularly into GAERS and Wistar rats every other day for 11 days. Before and after antibody administration, electroencephalography (EEG) recordings were performed to analyse spontaneous spike-and-wave discharges (SWDs) in GAERS. In Wistar rats, after the completion of antibody infusions, PTZ was administered (35 mg/kg) on the 12 th day to induce absence seizures. The occurrence of PTZ-induced SWDs was quantified. Results:NMDAR IgG significantly increased the duration and number of SWDs in GAERS compared to HC IgG. LGI1 IgG had no significant effect, suggesting a differential role of NMDAR and LGI1 antibodies in modulating SWD activity. Similarly, NMDAR IgG-treated Wistar rats showed increased susceptibility to PTZ-induced absence seizures, while LGI1 IgG did not cause significant changes in PTZ-induced SWDs. Conclusion:These results reveal a distinct pro-epileptogenic effect of NMDAR antibodies in both genetic and pharmacological models of absence epilepsy, while LGI1 antibodies appear to have a negligible effect. These findings suggest a specific role for NMDAR dysfunction in absence seizure pathophysiology and support further investigation into antibody-mediated seizure mechanisms.

Objective: Levetiracetam (LEV) is a broad-spectrum anti-seizure drug primarily prescribed for partial seizures. We aimed to compare the effects of LEV in two epilepsy models: the kindling model for temporal lobe epilepsy and the Genetic Absence Epilepsy Rats from Strasbourg (GAERS) model for absence epilepsy. Methods: GAERS and Wistar rats underwent stereotaxic surgery for cortical recording electrodes implantation, while bipolar stimulation electrodes were implanted in the right basolateral amygdala of Wistar rats for kindling stimulations. For the kindling procedure, Wistar rats were stimulated at after discharge (AD) threshold twice daily. After three consecutive stage five seizures, the animals were considered kindled and randomly divided into two groups. Kindled animals received intraperitoneal injection of either saline or 100 mg/kg LEV 1 hour before stimulation. Seizure stage, amygdala AD, and total seizure duration were evaluated. GAERS rats were randomly divided into two groups, and spike-and-wave discharges (SWDs) were recorded for 2 hours after intraperitoneally injecting 100 mg/kg LEV or saline. Cumulative SWD duration, number of SWDs, and mean duration of an individual SWD were compared with the saline-treated control group. Results: LEV significantly reduced the seizure severity and AD duration compared to controls. The mean seizure stage was 1.42 +/- 0.29 in the LEV group (p<0.0001) while all saline-treated kindled animals reached stage 5 seizure. LEV also lowered the total seizure duration (13.14 +/- 1.11 s) significantly compared to vehicle (86.76 +/- 12.59 s; p<0.005). In GAERS group, LEV suppressed the SWDs around 40 min after injection, and this anti-seizure effect lasted until the end of a 2-hour electroencephalography recording. Conclusion: LEV, at a dose, 100 mg/kg, effectively reduced convulsive and non-convulsive seizures in two different epilepsy models. These results underscore the efficacy of LEV in mitigating seizure severity and duration across different epilepsy types, suggesting its potential as a promising therapeutic agent for managing both focal and absence seizures.

There is a wealth of data indicating that the immune system plays an important role in seizure disorders. This includes autoimmune encephalitis, in which an immune response directed against neuronal antigens results in brain inflammation and subsequent seizure activity, as well as autoimmune-associated epilepsy and neuroinflammatory changes detected in the tissues of patients with epilepsy, in which context it is often difficult to distinguish whether the inflammation is causal or a consequence of the seizures. Here, we summarize the discussion on this topic held during the XVII Workshop on Neurobiology of Epilepsy (WONOEP XVII), organized in 2023 by the Neurobiology Commission of the International League Against Epilepsy on the topic of the extracellular space in epilepsy. This critical appraisal explores the progress, emerging concepts, and discussion on the immunopathogenesis of epilepsy, with a particular focus on the interplay between the immune system and the central nervous system, highlighting the role of autoimmunity, neuroinflammation, and neuroimmunological processes in the etiology of various epileptic disorders and the prospects for new therapies.

Epilepsy is a chronic neurological disorder marked by recurrent seizures, significantly impacting individuals worldwide. Current treatments are often ineffective for a third of patients and can cause severe side effects, necessitating new therapeutic approaches. Glial cells, particularly astrocytes, microglia, and oligodendrocytes, are emerging as crucial targets in epilepsy management. Astrocytes regulate neuronal homeostasis, excitability, and synaptic plasticity, playing key roles in maintaining the blood–brain barrier (BBB) and mediating neuroinflammatory responses. Dysregulated astrocyte functions, such as reactive astrogliosis, can lead to abnormal neuronal activity and seizure generation. They release gliotransmitters, cytokines, and chemokines that may exacerbate or mitigate seizures. Microglia, the innate immune cells of the CNS, contribute to neuroinflammation, glutamate excitotoxicity, and the balance between excitatory and inhibitory neurotransmission, underscoring their dual role in seizure promotion and protection. Meanwhile, oligodendrocytes, primarily involved in myelination, also modulate axonal excitability and contribute to the neuron–glia network underlying seizure pathogenesis. Understanding the dynamic interactions of glial cells with neurons provides promising avenues for novel epilepsy therapies. Targeting these cells may lead to improved seizure control and better clinical outcomes, offering hope for patients with refractory epilepsy.

Background and Aims: Anatolian propolis, which is rich in phenolic compounds, may offer neuroprotective benefits due to its anti-inflammatory and antioxidant properties. This study explored how Anatolian propolis affects the frequency of absence seizures and anxiety levels in rats with genetic absence epilepsy from Strasbourg (GAERS). Methods: Adult male GAERS were orally administered Anatolian propolis samples at concentrations of 15% (120 mg/kg/day) and 30% (180 mg/kg/day), whereas the control group received an equivalent volume of tap water by oral gavage for 35 days. A 3-h EEG was recorded 9.00 and 12.00 a.m after 35 days of sub-chronic administration. The effects of Anatolian propolis on spike-and-wave discharge (SWD) duration, number, and mean duration of each SWDs were evaluated and compared with the control group. The elevated plus maze test was then performed to measure the anxiety level of GAERS rats. Finally, brains were isolated, and interleukin-1 beta (IL-1 beta) levels were measured in freshly frozen isolated brains using an ELISA method. Results: Oral administration of Anatolian propolis (180 mg/kg/day) significantly reduced the number of SWDs and decreased IL-1 beta levels in the brain tissue of adult GAERS after 35 days of sub-chronic administration (p<0.05). Propolis treatment did not alter anxiety levels in terms of time spent in the closed and open arms. Conclusion: This study represents an initial exploration of the effects of Anatolian propolis on absence seizures in GAERS. Our findings indicate that Anatolian propolis could offer therapeutic advantages by reducing the levels of the brain's pro-inflammatory cytokine IL-1 beta in GAERS, potentially mitigating absence seizures. However, additional research is necessary to understand the potential mechanisms driving this benefit.

Astrocytes are specialized non-neuronal glial cells of the central nervous system, contributing to neuronal excitability and synaptic transmission (gliotransmission). Astrocytes play a key roles in epileptogenesis and seizure generation. Epilepsy, as a chronic disorder characterized by neuronal hyperexcitation and hypersynchronization, is accompanied by substantial disturbances of glial cells and impairment of astrocytic functions and neuronal signaling. Anti-seizure drugs that provide symptomatic control of seizures primarily target neural activity. In epileptic patients with inadequate control of seizures with available anti-seizure drugs, novel therapeutic candidates are needed. These candidates should treat epilepsy with anti-epileptogenic and disease-modifying effects. Evidence from human and animal studies shows that astrocytes have value for developing new anti-seizure and anti-epileptogenic drugs. In this review, we present the key functions of astrocytes contributing to neuronal hyperexcitability and synaptic activity following an etiology-based approach. We analyze the role of astrocytes in both development (epileptogenesis) and generation of seizures (ictogenesis). Several promising new strategies that attempted to modify astroglial functions for treating epilepsy are being developed: (1) selective targeting of glia-related molecular mechanisms of glutamate transport; (2) modulation of tonic GABA release from astrocytes; (3) gliotransmission; (4) targeting the astrocytic Kir4.1-BDNF system; (5) astrocytic Na+/K+/ATPase activity; (6) targeting DNA hypo- or hypermethylation of candidate genes in astrocytes; (7) targeting astrocytic gap junction regulators; (8) targeting astrocytic adenosine kinase (the major adenosine-metabolizing enzyme); and (9) targeting microglia-astrocyte communication and inflammatory pathways. Novel disease-modifying therapeutic strategies have now been developed, such as astroglia-targeted gene therapy with a broad spectrum of genetic constructs to target astroglial cells.

IntroductionOrexin is a neuropeptide neurotransmitter that regulates the sleep/wake cycle produced by the lateral hypothalamus neurons. Recent studies have shown the involvement of orexin system in epilepsy. Limited data is available about the possible role of orexins in the pathophysiology of absence seizures. This study aims to understand the role of orexinergic signaling through the orexin-type 2 receptor (OX2R) in the pathophysiology of absence epilepsy. The pharmacological effect of a selective OX2R agonist, YNT-185 on spike-and-wave-discharges (SWDs) and the OX2R receptor protein levels in the cortex and thalamus in adult GAERS were investigated.MethodsThe effect of intracerebroventricular (ICV) (100, 300, and 600 nmol/10 μL), intrathalamic (30 and 40 nmol/500 nL), and intracortical (40 nmol/500 nL) microinjections of YNT-185 on the duration and number of spontaneous SWDs were evaluated in adult GAERS. The percentage of slow-wave sleep (SWS) and spectral characteristics of background EEG were analyzed after the ICV application of 600 nmol YNT-185. The level of OX2R expression in the somatosensory cortex and projecting thalamic nuclei of adult GAERS were examined by Western blot and compared with the non-epileptic Wistar rats.ResultsWe showed that ICV administration of YNT-185 suppressed the cumulative duration of SWDs in GAERS compared to the saline-administered control group (p < 0.05). However, intrathalamic and intracortical microinjections of YNT-185 did not show a significant effect on SWDs. ICV microinjections of YNT-185 affect sleep states by increasing the percentage of SWS and showed a significant treatment effect on the 1–4 Hz delta frequency band power during the 1–2 h post-injection period where YNT-185 significantly decreased the SWDs. OXR2 protein levels were significantly reduced in the cortex and thalamus of GAERS when compared to Wistar rats.ConclusionThis study investigated the efficacy of YNT-185 for the first time on absence epilepsy in GAERS and revealed a suppressive effect of OX2R agonist on SWDs as evidenced by the significantly reduced expression of OX2R in the cortex and thalamus. YNT-185 effect on SWDs could be attributed to its regulation of wake/sleep states. The results constitute a step toward understanding the effectiveness of orexin neuropeptides on absence seizures in GAERS and might be targeted by therapeutic intervention for absence epilepsy.

ObjectiveAutoimmune encephalitis (AE) is a distinct neuro-immunological disorder associated with the production of autoantibodies against neuronal proteins responsible for pharmacoresistant seizures, cognitive decline and behavioral problems. To establish the causal link between leucine-rich glioma inactivated 1 (LGI1) antibody and seizures, we developed an in-vivo antibody-mediated AE rat model in which serum antibodies (IgG) obtained from blood samples of leucine-rich glioma inactivated 1 (LGI1) protein antibody (IgG) positive encephalitis patients were passively transferred into non-epileptic Wistar rats. Serum IgG of N-methyl-d-aspartate receptor (NMDAR) antibody positive patients were used as positive control since the pathogenicity of this antibody has been previously shown in animal models.MethodsTotal IgG obtained from the pooled sera of NMDAR and LGI1-IgG positive patients with epileptic seizures and healthy subjects was applied chronically every other day for 11 days into the cerebral lateral ventricle. Spontaneous seizure development was followed by electroencephalography. Behavioral tests for memory and locomotor activity were applied before and after the antibody infusions. Then, pentylenetetrazol (PTZ) was administered intraperitoneally to evaluate seizure susceptibility. Immunohistochemistry processed for assessment of hippocampal astrocyte proliferation and expression intensity of target NMDAR and LGI1 antigens.ResultsNo spontaneous activity was observed during the antibody infusions. PTZ-induced seizure stage was significantly higher in the NMDAR-IgG and LGI1-IgG groups compared to control. Besides, memory deficits were observed in the NMDAR and LGI1-IgG groups. We observed enhanced astrocyte proliferation in NMDAR- and LGI1-IgG groups and reduced hippocampal NMDAR expression in NMDAR-IgG group.SignificanceThese findings suggest that neuronal surface auto-antibody administration induces seizure susceptibility and disturbed cognitive performance in the passive transfer rat model of LGI1 AE, which could be a potential in-vivo model for understanding immune-mediated mechanisms underlying epileptogenesis and highlight the potential targets for immune-mediated seizures in AE patients.

Objective: Lacosamide (LCM) is a new generation antiepileptic drug that affects the slow inactivation of voltagegated sodium channels. We studied whether chronic LCM treatment prior to onset of absence seizures was able to prevent/reduce the development of absence seizures in GAERS rats, a well-validated animal model of absence epilepsy and epileptogenesis. Drug effects on the duration, mean duration, number and spectral characteristics of spike-wave discharges (SWDs) were measured both 1 and 2 months after treatment withdrawal and compared with the ethosuximide (ETX) that has anti-epileptogenic activity in GAERS. Furthermore, the acute effects of LCM on SWDs in adult GAERS were evaluated.Methods: GAERS rats were administered either with LCM (10 mg/kg/day or 30 mg/kg/day, i.p) or ETX (25 mg/ kg/day, i.p) or saline (%0.9 NaCl) until PN60 for 40 consecutive days starting from PN20. Animals were stereotaxically implanted with cortical screw electrodes under ketamine/xylazine anesthesia at PN53. Following recovery period, EEG were recorded at PN60 (last day of drug administration)- 61-62, PN90-91-92 and PN120-121-122 time periods for 3 consecutive days.Results: The chronic treatment with both LCM and ETX led to an ~50% reduction in the development of spontaneous absence seizures in GAERS at PN90 and PN120 after the treatment withdrawal at PN60. The spectral analysis of EEG data revealed significant slowing of the peak frequency of SWDs in LCM treated animals at PN62.Conclusion: These results confirm that chronic LCM treatment modifies the development of absence seizures in GAERS and suggest that LCM exerts beneficial effects on absence seizure epileptogenesis.

INTRODUCTION:Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel currents of Ih and absence epilepsy seizures are associated, but studies reveal differential results.OBJECTIVE:In our study, we aimed to investigate the role of the HCN channels on the expression of spike-and-wave discharges (SWDs) using the Genetic Absence Epilepsy Rats from Strasbourg (GAERS) model.METHODS:HCN isoform levels from isolated brains of both naïve nonepileptic Wistar and GAERS groups were evaluated by enzyme-linked immunosorbent assay. ZD7288, an Ih inhibitor as well as an HCN channel antagonist, was administered intracerebroventricularly to the adult GAERS groups, and to evaluate their SWD activities, electroencephalography was recorded. The effect of ZD7288 on the cumulative total duration and number of SWDs and the mean duration of each SWD complex was evaluated.RESULTS:The HCN2 levels in the cortex and hippocampus of the GAERS group were lower compared to the naïve nonepileptic Wistar group (p < 0.05). ZD7288 increased the number of SWDs at the 20th and 120th min with the highest administered dose of 7 μg (p < 0.05).CONCLUSION:The Ih inhibitor ZD7288 increased the number of SWDs in a genetic absence epilepsy rat model, although this increase may not be significant due to the inconsistent time-dependent effects. In GAERS, the cortical and hippocampal HCN2 channel levels were significantly lower compared to the control group. Further studies are needed with higher doses of ZD7288 to determine if the effects will increase drastically.

Spike-and-wave discharge is a phenomenon that occurs during absence epilepsy. The detection of these waveforms can provide an important tool for the different aspects of epilepsy. However, the manual detection of these seizures is not simple as it can take hours to be detected. In this study, we developed a promising tool to detect the spike and wave discharges automatically from a recorded EEG signal depending on the amplitude characteristics and frequency spectrum. The results are promising as the false and missed detection rates are less than 3%, whereas the time overlap between the manually and automatically detected wave-forms is greater than 96%.

Objective The role of alpha(2A) adrenergic receptors (alpha(2A)ARs) in absence epilepsy is not well characterized. Therefore, we investigated the outcomes of the specific antagonism of alpha(2A)ARs on the spike-and-wave discharges (SWDs) in genetic absence epilepsy rats from Strasbourg (GAERSs), together with its influence on the behavior and second messenger systems, which may point to the mechanisms to which a possible SWD modulation can be related. Methods Atipamezole, an alpha(2A)AR antagonist, was administered intracerebroventricularly to the adult GAERSs, and electroencephalography (EEG) was conducted. The cumulative duration and number of SWDs, and the mean duration of each SWD complex were counted. The relative power of the EEG frequency bands and behavioral activity after the acute application of two doses (12 and 31 mu g/5 mu L) of atipamezole were evaluated. The levels of cyclic adenosine monophosphate and calcium/calmodulin-dependent kinase II (CaMKII) were measured in the cortex, thalamus, and hippocampus of naive Wistar rats and GAERSs, administered with artificial cerebrospinal fluid (aCSF) as a vehicle, or either acute or chronic atipamezole (12 mu g), the latter being administered for 5 consecutive days. Results Atipamezole significantly suppressed SWDs dose-dependently, without affecting the relative power values of EEG frequency spectrum. The stereotypic activity was significantly lower in both naive Wistar rats and GAERSs receiving the highest dose (31 mu g) of atipamezole compared to GAERSs receiving aCSF. In GAERSs, CaMKII levels were found to be higher in the thalamus after the acute and chronic application of SWD-suppressing doses of atipamezole (12 and 31 mu g) compared to aCSF. Significance This study emphasizes the alpha(2)AR-related modulation of absence epilepsy and particularly the significance of alpha(2)AR antagonism in suppressing SWDs. Atipamezole's SWD-suppressive actions may be through CaMKII-mediated second messenger systems in the thalamus.

OBJECTIVE:This study aimed to investigate the effects of γ-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.

Objectives: Rho/Rho-kinase (ROCK) signaling has been shown to contribute to neuroinflammation, epileptogenesis, and seizures in convulsive-type epilepsy models. However, this pathway has not been investigated in the pathophysiology of absence epilepsy. The aim of this study was to investigate ROCK activity in brain regions involved in spike-and-wave discharge (SWD) generation and the effects of the Rho-kinase inhibitor, Y-27632, on ROCK activity in genetic absence epilepsy rats from Strasburg (GAERS). Methods: ROCK activity in the somatosensorial cortex, hippocampus, and thalamus was measured using an enzyme-linked immunosorbent assay (ELISA). An intracerebroventricular (i.c.v.) injection of Y-27632 was administered at a dose of 20 nmol/5 mu l and changes in ROCK activity were assessed. To evaluate the effect of Y-27632 on SWDs, i.c.v. 20 nmol and 60 nmol doses of Y-27632 were administered to the GAERS subjects and electroencephalography was performed. Results: ROCK activity was elevated in the somatosensory cortex in the GAERS study subjects, and the Rho-kinase enzyme inhibitor, Y-27632, suppressed this increase. In addition, Y-27632 significantly reduced the total and mean duration of SWDs compared with the control group. Conclusion: The findings indicate that the Rho-kinase pathway may play a role in the generation of absence seizures, and that the suppressive effect of Y-27632 on SWDs may be a potential therapeutic target for this anti-absent effect.

Introduction: Clopidogrel treatment is one of the standard treatments in terms of reducing mortality and morbidity in patients with cerebrovascular disease diagnosed with large artery atherosclerosis. However, resistance to clopidogrel treatment is a significant problem today. In this study, we aimed to retrospectively investigate clopidogrel resistance (CR) and related factors in patients with detected large artery atherosclerosis who were evaluated for cerebrovascular disease. Methods: A total of 96 patients, including 31 females and 65 males, were evaluated in the neurology and neuroradiology clinics with the diagnosis of cerebrovascular disease. Age, gender, presence of CR, and complete blood count values [platelet count (PIT), platelecrit (PCT), mean platelet volume, white blood cells, platelet distribution width] were evaluated. Impedance Aggregometry was used to evaluate CR in the study. The results were given as the area under the curve. An adenosine diphosphate value higher than 46 U was taken as a resistance indicator. The relationship between blood tests and CR was investigated. Results: CR was detected in 33.3% (n=32) of 96 patients. PLT (295.7 +/- 12.4) and PCT values (0.3 +/- 0.01) were significantly higher in patients with resistance than those without resistance (p<0.005). Conclusion: This study shows that high PLT and PCT values can be used to predict CR.

Objective: Recent data indicate that amygdala kindling leads to significant changes in interictal neuronal firing patterns of thalamic reticular nucleus (TRN) neurons by decreasing the spontaneous firing rate and increasing burst firing in nonepileptic control (NEC) rats. Genetic Absence Epilepsy Rats From Strasbourg (GAERS) were resistant to these kindling-induced firing changes in TRN neurons, and are also resistant to the progression of kindling. We investigated whether a homozygous, missense, single nucleotide mutation (R1584P) in the Ca(v)3.2 T-type Ca2+ channel gene, which has been correlated with the expression of absence seizures in GAERS, influenced kindling progression and TRN firing patterns. Methods: Double-crossed (GAERS vs NEC; F2) rats that were homozygous for the Ca(v)3.2 mutation (PP) and those negative for the mutation (RR) were implanted with a stimulating electrode in the amygdala. Rats received a total of 30 kindling stimulations at their afterdischarge threshold current twice daily, and kindling progression was evaluated. Thereafter, the extracellular neuronal activity of TRN neurons was recorded in vivo under neuroleptanesthesia to investigate the influence of Ca(v)3.2 mutation on TRN firing patterns. Results: We found that the R1584P mutation did not affect kindling progression in F2 crosses (P = 0.78). However, it influenced kindling-induced neuronal firing of TRN neurons. After 30 stimulations, RR rats exhibited a lower firing rate and a higher percentage of burst firing compared to PP rats. The decrease in firing frequency was correlated with the increase in the amount of burst firing in RR rats (R-2 = 0.497). Significance: Our findings suggest that mutation in Ca(v)3.2 T-type Ca2+ channels may play a role in the resistance to kindling-induced changes in TRN neurons to a low-frequency and high-percentage bursting pattern seen in association with the convulsive stages of amygdala kindling, but is not in itself enough to explain the resistance to kindling progression observed in GAERS.

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and the Ih current they generate contribute to the pathophysiological mechanisms of absence seizures (ASs), but their precise role in neocortical and thalamic neuronal populations, the main components of the network underlying AS generation, remains controversial. In diverse genetic AS models, Ih amplitude is smaller in neocortical neurons and either larger or unchanged in thalamocortical (TC) neurons compared with nonepileptic strains. A lower expression of neocortical HCN subtype 1 channels is present in genetic AS-prone rats, and HCN subtype 2 knock-out mice exhibit ASs. Furthermore, whereas many studies have characterized Ih contribution to "absence-like" paroxysmal activity in vitro, no data are available on the specific role of cortical and thalamic HCN channels in behavioral seizures. Here, we show that the pharmacological block of HCN channels with the antagonist ZD7288 applied via reverse microdialysis in the ventrobasal thalamus (VB) of freely moving male Genetic Absence Epilepsy Rats from Strasbourg decreases TC neuron firing and abolishes spontaneous ASs. A similar effect is observed on γ-hydroxybutyric acid-elicited ASs in normal male Wistar rats. Moreover, thalamic knockdown of HCN channels via virally delivered shRNA into the VB of male Stargazer mice, another genetic AS model, decreases spontaneous ASs and Ih-dependent electrophysiological properties of VB TC neurons. These findings provide the first evidence that block of TC neuron HCN channels prevents ASs and suggest that any potential anti-absence therapy that targets HCN channels should carefully consider the opposite role for cortical and thalamic Ih in the modulation of absence seizures. SIGNIFICANCE STATEMENT Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels play critical roles in the fine-tuning of cellular and network excitability and have been suggested to be a key element of the pathophysiological mechanism underlying absence seizures. However, the precise contribution of HCN channels in neocortical and thalamic neuronal populations to these nonconvulsive seizures is still controversial. In the present study, pharmacological block and genetic suppression of HCN channels in thalamocortical neurons in the ventrobasal thalamic nucleus leads to a marked reduction in absence seizures in one pharmacological and two genetic rodent models of absence seizures. These results provide the first evidence that block of TC neuron HCN channels prevents absence seizures.