Validation of the 6Hz refractory seizure mouse model for intracerebroventricularly administered compounds

Walrave, Laura; Maes, Katrien; Coppens, Jessica; Bentea, Eduard; Eeckhaut, Ann Van; Massie, Ann; Liefferinge, Joeri Van; Smolders, Ilse Julia

doi:10.1016/j.eplepsyres.2015.06.003

Cited by 24 publications

(27 citation statements)

References 26 publications

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“…To exclude that the anticonvulsant effects of TAT‐Gap19 against pilocarpine‐induced seizures are model‐dependent, we next continued with compound testing in electrical models for seizures and epilepsy. Considering the need to test candidate drugs in models of pharmacoresistant seizures, we investigated whether TAT‐Gap19 shows effects in the acute 6 Hz mouse model of electrically‐induced refractory seizures (Barton, Klein, Wolf, & White, ; Walrave et al, ). Noteworthy, this model was recently added to the Epilepsy Therapy Screening Program (ETSP) of the National Institute of Neurological Disorders and Stroke (NINDS; Barker‐Haliski et al, ).…”

Section: Resultsmentioning

confidence: 99%

“…Limbic psychomotor seizures were evoked via corneal stimulation (6 Hz, 0.2 ms rectangular pulse width, 3 s duration) using an ECT Unit 57800 stimulator (Ugo Basile, Varese, Italy). All experiments were performed at a current intensity of 49 mA, found to be optimal in a current‐response study (Walrave et al, ). A drop of 0.5% xylocaine (AstraZeneca, Brussels, Belgium) in saline was applied to the eyes to induce local anesthesia and ensure good conductivity.…”

Section: Methodsmentioning

confidence: 99%

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Inhibition of astroglial connexin43 hemichannels with TAT‐Gap19 exerts anticonvulsant effects in rodents

Walrave

Pierre

Albertini

et al. 2018

Glia

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Accumulating evidence shows a key function for astrocytic connexin43 (Cx43) signaling in epilepsy. However, the lack of experimental distinction between Cx43 gap junction channels (GJCs) and hemichannels (HCs) has impeded the identification of the exact contribution of either channel configurations to epilepsy. We therefore investigated whether TAT-Gap19, a Cx mimetic peptide that inhibits Cx43 HCs but not the corresponding Cx43 GJCs, influences experimentally induced seizures in rodents. Dye uptake experiments in acute hippocampal slices of mice demonstrated that astroglial Cx43 HCs open in response to the chemoconvulsant pilocarpine and this was inhibited by TAT-Gap19. In vivo, pilocarpine-induced seizures as well as the accompanying increase in D-serine microdialysate levels were suppressed by Cx43 HC inhibition. Moreover, the anticonvulsant action of TAT-Gap19 was reversed by exogenous D-serine administration, suggesting that Cx43 HC inhibition protects against seizures by lowering extracellular D-serine levels. The anticonvulsive properties of Cx43 HC inhibition were further confirmed in electrical seizure mouse models, i.e. an acute 6 Hertz (Hz) model of refractory seizures and a chronic 6 Hz corneal kindling model. Collectively, these results indicate that Cx43 HCs play a role in seizures and underscore their potential as a novel and druggable target in epilepsy treatment.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Inhibition of astroglial connexin43 hemichannels with TAT‐Gap19 exerts anticonvulsant effects in rodents

Walrave

Pierre

Albertini

et al. 2018

Glia

Self Cite

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“…Moreover, the 6 Hz assay may identify compounds with potentially novel mechanisms of action for the treatment of focal seizures in humans, including anti‐inflammatory agents like minocycline, serotonin receptor agonists, and adenosine receptor agonists . Variations on the protocol of Barton and colleagues certainly exist; for example, Walrave and colleagues report seizure duration as a reliable outcome measure in the 6 Hz assay and provide an approach for target validation using intracerebroventricular (i.c.v.) delivery of promising test compounds with unknown or limited blood–brain barrier permeability.…”

Section: Example Crfsmentioning

confidence: 99%

“…Although the 6 Hz approach is widely used in mice, there is no consensus on the endpoints to define anticonvulsant protection: some groups describe protection as the presence or absence of seizures, 16 whereas others consider an animal to be protected if it resumes normal exploratory behavior within 7-10 s after stimulation such that total seizure duration (in seconds) is an additional endpoint measure. 27,28 For these reasons, the various endpoint measures to be included in the study should be defined clearly in the 6 Hz CRF module. As with MES, binary endpoint measurements (protected/not protected) based on the specific seizure endpoints will accommodate an ED 50 determination.…”

Section: Stimulation Protocolmentioning

confidence: 99%

A companion to the preclinical common data elements for pharmacologic studies in animal models of seizures and epilepsy. A Report of the TASK3 Pharmacology Working Group of the ILAE/AES Joint Translational Task Force

et al. 2018

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SummaryPreclinical pharmacology studies in animal models of seizures and epilepsy have provided a platform to identify more than 20 antiseizure drugs in recent decades. To minimize variability in lab‐to‐lab studies and to harmonize approaches to data collection and reporting methodology in pharmacologic evaluations of the next generation of therapies, we present common data elements (CDEs), case report forms (CRFs), and this companion manuscript to help with the implementation of methods for studies in established preclinical seizure and epilepsy models in adult rodents. The development of and advocacy for CDEs in preclinical research has been encouraged previously by both clinical and preclinical groups. It is anticipated that adoption and implementation of these CDEs in preclinical studies may help standardize approaches to minimize variability and increase the reproducibility of preclinical studies. Moreover, they may provide a methodologic framework for pharmacology studies in atypical animal models or models in development, which may ultimately promote novel therapy development. In the present document, we refer selectively to animal models that have a long history of preclinical use, and in some cases, are clinically validated.

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“…Indeed, the 6-Hz corneal stimulation model has been included in the anticonvulsant screening project established by the National Institutes of Neurological Disorders and Stroke (Smith et al, 2007). Additionally, this model has been adopted to propose a new kindling protocol, also aimed at identifying new effective AEDs (Walrave et al, 2015). Despite the large use of 6-Hz corneal stimulation to induce convulsions, the cerebral regions participating to seizures induced in this model are still largely undetermined.…”

Section: Introductionmentioning

confidence: 99%

Progressive Seizure Aggravation in the Repeated 6-Hz Corneal Stimulation Model Is Accompanied by Marked Increase in Hippocampal p-ERK1/2 Immunoreactivity in Neurons

Giordano

Costa

Lucchi

et al. 2016

Front. Cell. Neurosci.

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The 6-Hz corneal stimulation test is used to screen novel antiepileptic molecules to overcome the problem of drug refractoriness. Although recognized as a standard test, it has been evaluated only recently in the attempt to characterize the putative neuronal networks involved in seizures caused by corneal stimulation. In particular, by recording from the CA1 region we previously established that the hippocampus participates to propagation of seizure activity. However, these findings were not corroborated by using markers of neuronal activation such as FosB/ΔFosB antigens. In view of this discrepancy, we performed new experiments to characterize the changes in levels of phosphorylated extracellular signal-regulated kinases1/2 (p-ERK1/2), which are also used as markers of neuronal activation. To this aim, mice underwent corneal stimulation up to three different times, in three sessions separated by an interval of 3 days. To characterize a group in which seizures could be prevented by pharmacological treatment, we also considered pretreatment with the ghrelin receptor antagonist EP-80317 (330 μg/kg). Control mice were sham-treated. Video electrocorticographic (ECoG) recordings were obtained from mice belonging to each group of treatment. Animals were finally used to characterize the immunoreactivity for FosB/ΔFosB and p-ERK1/2 in the hippocampus. As previously shown, FosB/ΔFosB levels were highly increased throughout the hippocampus by the first induced seizure but, in spite of the progressively increased seizure severity, they were restored to control levels after the third stimulation. At variance, corneal stimulation caused a progressive increase in p-ERK1/2 immunoreactivity all over the hippocampus, especially in CA1, peaking in the third session. Predictably, EP-80317 administration reduced both duration and severity of seizures, prevented the increase in FosB/ΔFosB levels in the first session, and partially counteracted the increase in p-ERK1/2 levels in the third session. The vast majority of p-ERK1/2 immunopositive cells were co-labeled with FosB/ΔFosB antibodies, suggesting the existence of a relationship between the investigated markers in a subpopulation of neurons activated by seizures. These findings suggest that p-ERK1/2 are useful markers to define the aggravation of seizures and the response to anticonvulsant treatments. In particular, p-ERK1/2 expression clearly identified the involvement of hippocampal regions during seizure aggravation in the 6-Hz model.

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Validation of the 6Hz refractory seizure mouse model for intracerebroventricularly administered compounds

Cited by 24 publications

References 26 publications

Inhibition of astroglial connexin43 hemichannels with TAT‐Gap19 exerts anticonvulsant effects in rodents

Inhibition of astroglial connexin43 hemichannels with TAT‐Gap19 exerts anticonvulsant effects in rodents

A companion to the preclinical common data elements for pharmacologic studies in animal models of seizures and epilepsy. A Report of the TASK3 Pharmacology Working Group of the ILAE/AES Joint Translational Task Force

Progressive Seizure Aggravation in the Repeated 6-Hz Corneal Stimulation Model Is Accompanied by Marked Increase in Hippocampal p-ERK1/2 Immunoreactivity in Neurons

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