Acute heat stress model of seizures in weanling rats: influence of prototypic anti-seizure compounds

The NMDA receptor complex as a therapeutic target in epilepsy: a review

A substantial amount of research has shown that N-methyl-D-aspartate receptors (NMDARs) may play a key role in the pathophysiology of several neurological diseases, including epilepsy. Animal models of epilepsy and clinical studies demonstrate that NMDAR activity and expression can be altered in association with epilepsy and particularly in some specific seizure types. NMDAR antagonists have been shown to have antiepileptic effects in both clinical and preclinical studies. There is some evidence that conventional antiepileptic drugs may also affect NMDAR function. In this review, we describe the evidence for the involvement of NMDARs in the pathophysiology of epilepsy and provide an overview of NMDAR antagonists that have been investigated in clinical trials and animal models of epilepsy.

Protective effect of the KCNQ activator flupirtine on a model of repetitive febrile seizures

Activation of KCNQ-channels has been shown to decrease or reduce the propagation of neuronal excitation in the immature central nervous system, and KCNQ activators represent a new class of anticonvulsant compounds. Their effectiveness has been demonstrated in many seizure models but not in repetitive febrile seizures (RFS) models. This study aimed to test whether the KCNQ channel activator flupirtine is also effective for RFS in rats. RFS were induced in Sprague-Dawley (SD) rats at postnatal day 10 (P10) in a warm water bath for eight consecutive days with or without the pre-administration of flupirtine or phenobarbital. As results, both drugs significantly increased the latency and decreased the rate of febrile seizures. Furthermore, seizures in the flupirtine group had a significantly shorter duration and were less severe compared with the phenobarbital group. The flupirtine-treated group showed less impairment in learning and memory and less obvious pathological changes in the brain following RFS compared with the phenobarbital-treated group. In summary, flupirtine appears to be effective in RFS prophylaxis and may merit further study as a candidate for the treatment of RFS in infants and children.

Effects of remacemide in two models of genetically determined generalized epilepsy, the GAERS and the audiogenic Wistar AS

The antiepileptic effects of remacemide were assessed in two models of genetically determined generalized epilepsy. The model of non-convulsive epilepsy used was a model of absence seizures, the GAERS (genetic absence epilepsy rats from Strasbourg), and the model of convulsive seizures was an audiogenic rat model, the Wistar AS. In the eight GAERS studied, the three doses of remacemide (20, 40, and 80 mg/kg) dose-dependently reduced the expression of spike-and-wave discharges (SWDs) that had almost totally disappeared at the highest dose used, 80 mg/kg. However, at the latter dose, the effect of remacemide may be partly due to a change in the vigilance level of the animals. In the Wistar AS, the dose of 20 mg/kg prolonged by twofold the latencies to wild running and tonic seizures, and prevented their expression in one rat out of the eight studied. At 40 mg/kg, the expression of wild running and tonic seizures was inhibited in seven and maintained in one of the eight rats studied. The present results support the effects of remacemide in tonic/clonic seizure, which was the first target of the drug, and confirm the effect of the anticonvulsant on absence seizures.

Remacemide: current status and clinical applications

Remacemide (RMC) is a non-competitive, low-affinity N-methyl-D-aspartate (NMDA) receptor antagonist that does not cause the behavioural and neuropathological side effects seen with other NMDA receptor antagonists. RMC and its active metabolite, AR-R 12495 AR, which has moderate affinity for the NMDA receptor, also interact with voltage-dependent neuronal sodium channels. Both agents show efficacy in a variety of animal models of epilepsy, parkinsonism and cerebral ischaemia. There is no evidence for teratogenicity or genotoxicity. RMC delays the absorption of L-dopa and elevates the concentrations of drugs metabolised by the hepatic cytochrome P450 3A4 isoform. RMC and AR-R 12495 AR have moderate protein binding and linear pharmacokinetics. Controlled studies show evidence of efficacy in treating epilepsy and Parkinson's disease. Post-surgical outcomes in RMC-treated patients at risk for intra-operative cerebral ischaemia are also encouraging. Adverse effects are related to the gastrointestinal and central nervous systems. RMC is a promising drug with numerous potential applications for both acute or chronic conditions associated with glutamate-mediated neurotoxicity.