Causes and consequences of pathogenic processes in evolution: implications from experimental epilepsy in animals

Cerebellar contribution to absence epilepsy

The new aggregate data analyses revealed the earlier missing role of cerebellum long-term electrical stimulation in the absence epilepsy. Neurophysiologic data gained by authors favor that cerebellar serial deep brain stimulation (DBS) (100 Hz) causes the transformation of penicillin-induced cortical focal discharges into prolonged 3,5-3,75 sec oscillations resembling spike-wave discharges (SWD) in cats. Such SWDs were not organized in the form of bursts and persisted continuously after stimulation. Therefore, the appearance of prolonged periods of SWD is regarded as a tonic cerebellar influence upon pacemaker of SWD and might be caused by the long-lasting DBS-induced increase of GABA-ergic extrasynaptic inhibition in the forebrain networks. The absence seizure facilitation caused by cerebellar DBS was discussed with the reviewed data on optogenetic stimulation, neuronal activity of cerebellar structures, and imaging data.

[Experimental models of epilepsy]

INTRODUCTION

An epileptic seizure is a clinical event and epilepsy is rather a group of symptoms than a disease. The main features all epilepsies have in common include, spontaneous occurrence, repetitiveness, and ictal correlation within the EEG. Epilepsies are manifested with distinct EEG changes, requiring exact clinical definition and consequential treatment. Current data show that 1% of the world's population (approximately 50 million people) suffers from epilepsy, with 25% of patients bpeing refractory to therapy and requiring search for new substances in order to decrease EEG and behavioral manifestations of epilepsies.

MATERIAL AND METHODS

In regard to discovery and testing of anticonvulsant substances the best results were achieved by implementation of experimental models. Animal models of epilepsy are useful in acquiring basic knowledge regarding pathogenesis, neurotransmitters (glutamate), receptors (NMDA/AIPA/kainate), propagation of epileptic seizures and preclinical assessment of antiepileptics (competitive and non-competitive NMDA antagonists).

RESULTS AND CONCLUSIONS

In our lab, we have developed a pharmacologic model of a (metaphit, NMDA and remacemide-cilastatin) generalized, reflex, and audiogenic epilepsy. The model is suitable for testing various anticonvulsant substances (e.g. APH, A4P, CPP, Mk-801) and potential antiepileptics (e.g. DSIP, its tetra- and octaanalogues).