Electrical stimulation of substantia nigra pars reticulata is anticonvulsant in adult and young male rats

Electrical stimulation of deep brain structures has been used for pain relief and treatment of refractory Parkinson's disease. Recently, stimulation of the subthalamic nucleus or anterior nuclei of the thalamus was introduced for the treatment of refractory epilepsy when other treatments failed. The substantia nigra pars reticulata (SNR) is another crucial site involved in the control of seizures. We studied the effects of continuous electrical stimulation of the SNR as a function of age in male rats. Adult [postnatal day (PN) 601 and young (PN 15) rats with electrodes symmetrically implanted in the SNR were used. The rats were stimulated with continuous constant current pulses (130 Hz) and simultaneously challenged with flurothyl to induce seizures. Control rats had the electrodes implanted but were not stimulated. High-frequency electrical stimulation of the SNR had anticonvulsant effects in both age groups. However, we identified age-specific features: In PN 60 rats, both unilateral and bilateral stimulation of the anterior region of the SNR produced anticonvulsant effects against clonic seizures, while stimulation of the posterior region of the SNR was ineffective. Stimulation of either SNR region had no effects on tonic-clonic seizures. In PN 15 rats, irrespective of the stimulation site within the SNR, bilateral stimulations of the SNR produced anticonvulsant effects against both clonic and tonic-clonic flurothyl-induced seizures, while unilateral stimulation was without effect. The data suggest that the SNR may be a candidate site for deep brain stimulation for the treatment of epilepsy. (C) 2002 Elsevier Science.