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The glycine co-agonist binding site of the N-methyl-D-aspartat (NMDA) receptor is discussed as an interesting target for different central nervous system diseases. Antagonism at this co-agonist site has been suggested as an alternative to the use of non-competitive or competitive NMDA receptor antagonists, which are associated with a pronounced adverse effect profile in chronic epilepsy models and epilepsy patients. In the present study, we addressed the hypothesis that sub-chronic administration of the glycine-binding site antagonist L-701,324 might exert disease-modifying effects in fully kindled mice during a period with frequent seizure elicitation (massive kindling). Moreover, we analyzed whether L-701,324 exposure during this phase affects the subsequent response to an antiepileptic drug. L-701,324 treatment during the massive kindling phase did not affect ictogenesis. Mean seizure severity and cumulative seizure duration proved to be comparable between vehicle- and L-701,324-treated mice. Following withdrawal of L-701,324 seizure thresholds did not differ in a significant manner from those in animals that received vehicle injections. A low dosage of phenobarbital caused a significant increase of the generalized seizure threshold in the L-701,324 pre-treated group, whereas it did not exert a comparable effect in animals that received vehicle during the massive kindling phase. Analysis of P-glycoprotein in the hilus of the hippocampus revealed lower expression rates in L-701,324 pre-treated kindled mice. In conclusion, the data indicate that targeting of the NMDA receptor glycine-binding site does not result in anticonvulsant or disease-modifying effects. However, it might improve antiepileptic drug responses. The findings might be linked to an impact on P-glycoprotein expression. However, future studies are necessary to further evaluate the mechanisms and assess the potential of respective add-on approaches., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Objective: The present study was aimed at determining the effect of eslicarbazepine acetate (ESL), eslicarbazepine and (R)-licarbazepine administration in the mouse corneal kindling and amygdala kindling models., Methods: NMRI mice were kindled by bilateral corneal stimulation twice daily. In amygdala kindling, mice were stimulated once daily via an implanted depth electrode until 10 generalized seizures were elicited. Maximal electroshocks (MES) were administered via corneal electrodes., Results: The average number of stimulations to reach a fully kindled generalized seizure was markedly increased by ESL. Administration of eslicarbazepine also inhibited the acquisition of kindling, whereas administration of R-licarbazepine did not affect the number of stimulations necessary to induce a specific seizure stage, and did not exert any relevant effect on mean seizure severity during kindling progression. ESL dose-dependently increased the focal seizure threshold and reduced seizure severity in amygdala kindling. Whereas eslicarbazepine treatment increased the afterdischarge threshold in a significant manner, (R)-licarbazepine treatment failed to exert a significant effect on thresholds in fully kindled mice. Administration of ESL and of eslicarbazepine significantly protected mice against MES-induced seizures, whereas that of (R)-licarbazepine failed to provide protection., Conclusions: These data provide evidence of the anticonvulsant effect of ESL and its active metabolite eslicarbazepine on partial-onset seizures in corneal and amygdala kindling models. Based on an effect of the parent compound and the active metabolite eslicarbazepine, ESL treatment may not merely suppress seizure activity but may also provide a disease-modifying or antiepileptogenic effect. Future studies will be necessary to further evaluate a putative preventive effect, in particular when considering that re-stimulation following wash-out did not indicate a persistent effect. The findings reported here raise doubts on the contribution of (R)-licarbazepine as an active anticonvulsant., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The prostaglandin E2 EP1 receptor as well as the inflammatory enzyme cyclooxygenase-2 have been suggested as targets for disease modulation, improvement of therapeutic response, and restoration of pharmacosensitivity in epilepsies. Translational development of respective add-on approaches requires careful analysis of putative effects on ictogenesis. Therefore we evaluated the impact of the EP1 receptor antagonist SC-51089, the EP1 receptor agonist misoprostol and the COX-2 inhibitors celecoxib and NS-398 in the mouse amygdala kindling model of temporal lobe epilepsy. Neither celecoxib nor NS-398 affected the generation, spread and termination of seizure activity. Whereas SC-51089 did not affect the seizure threshold, the highest dose (30mg/kg) significantly decreased the seizure severity when administered 60min before stimulation. Moreover, SC-51089 significantly prolonged seizure duration at the highest dose. The EP1 receptor agonist misoprostol exerted contrasting effects on seizure duration with a significant decrease in the duration of motor seizure activity. The data suggest that doses of COX-2 inhibitors and EP1 receptor antagonists which exert disease modulating or antiepileptic drug potentiating effects do not negatively affect seizure control in temporal lobe epilepsy. The contrasting impact of the EP1 receptor antagonist and agonist suggests that EP1 receptors can influence endogenous mechanisms involved in termination of seizure activity., (Copyright 2010 Elsevier B.V. All rights reserved.)

Pyrrolidine dithiocarbamate (PDTC) has a dual mechanism of action as an antioxidant and an inhibitor of the transcription factor kappa-beta. Both, production of reactive oxygen species as well as activation of NF-kappaB have been implicated in severe neuronal damage in different sub-regions of the hippocampus as well as in the surrounding cortices. The effect of PDTC on status epilepticus-associated cell loss in the hippocampus and piriform cortex was evaluated in the rat fractionated pilocarpine model. Treatment with 150 mg/kg PDTC before and following status epilepticus significantly increased the mortality rate to 100%. Administration of 50 mg/kg PDTC (low-dose) did not exert major effects on the development of a status epilepticus or the mortality rate. In vehicle-treated rats, status epilepticus caused pronounced neuronal damage in the piriform cortex comprising both pyramidal cells and interneurons. Low-dose PDTC treatment almost completely protected from lesions in the piriform cortex. A significant decrease in neuronal density of the hippocampal hilar formation was identified in vehicle- and PDTC-treated rats following status epilepticus. In conclusion, the NF-kappaB inhibitor and antioxidant PDTC protected the piriform cortex, whereas it did not affect hilar neuronal loss. These data might indicate that the generation of reactive oxygen species and activation of NF-kappaB plays a more central role in seizure-associated neuronal damage in the temporal cortex as compared to the hippocampal hilus. However, future investigations are necessary to exactly analyze the biochemical mechanisms by which PDTC exerted its beneficial effects in the piriform cortex.