The nigral control of epilepsy: does this concept also apply to pharmacoresistant focal epilepsy? Volume 16, issue 2, Avril-Mai-Juin 2004


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JE 2413 MRNT‐Université Joseph Fourier, « Contrôle des Réseaux Synchrones Epileptiques », UFR Biologie, Bât. B, 2280, rue de la Piscine, 38400 Saint Martin d’Hères, France

In several animal models of generalized epileptic seizures, the inhibition of the substantia nigra has been shown to have antiepileptic effects. However, no evidence, so far, has been provided concerning the nigral’ control of partial epilepsies without secondary generalisation, epilepsies for which current pharmacological treatments do not always allow a complete suppression of seizures. The effects of a GABAergic inhibition of the substantia nigra were investigated in mice with chronic pharmaco‐resistant focal seizures induced by local injections of kainic acid in the dorsal hippocampus. The bilateral intranigral injection of muscimol induced a decreased number of seizures for more than one hour. Stereoptypies occur during the first 30 min postinjection. The antiepileptic effect, devoid of any behavioral side‐effects, persists thereafter. Deep EEG recordings performed during the epileptogenesis in these mice, show the occurrence of concomitant oscillations at the nigral and hippocampal levels. Furthermore, bilateral intranigral 130 Hz stimulations suppressed seizures independently of any behavioral side‐effects. Altogether, this pharmacological and electrophysiological data suggests that the concept of the nigral control of seizures could also be applied to pharmacoresistant partial epileptic seizures.