The Effects of Bilateral Continuous Subthalamic Nucleus Stimulation in an Animal Model of Acute Seizures
Abstract number :
2.073
Submission category :
Year :
2001
Submission ID :
801
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
A. Pan, M.D., Epilepsy, Cleveland Clinic Foundation, Cleveland, OH; I. Najm, M.D., Epilepsy, Cleveland Clinic Foundation, Cleveland, OH; A. Boongird, M.D., Epilepsy, Cleveland Clinic Foundation, Cleveland, OH; T. Kunieda, M.D., Epilepsy, Cleveland Clinic
RATIONALE: It is hypothesized that the Dorsal Midbrain Anti-convulsant Zone (DMAZ) in the superior colliculus is under inhibitory control by efferents from the Substancia Nigra pars reticulata (SNpr). Inhibiting the subthalamic nucleus (STN) could release the inhibitory effect of SNpr on DMAZ & thus activate the latter, raising seizure threshold. Continuous, bilateral, high frequency electrical stimulation may inhibit STN. We investigate the effects of this on an acute animal model of kainate-induced seizures.
METHODS: Eight Sprague-Dawley rats (weight 178-300g) were implanted with bilateral STN electrodes & epidural (hippocampal depth electrodes in 2 rats) recording electrodes. 3-5 days post-surgically, baseline cortical & depth EEG recordings were documented. All rats then underwent subcutaneous kainic acid (KA) injection (10mg/kg) under continuous video-EEG monitoring for 1 hour. Epileptiform activity was terminated at 1 hour post-KA injection with intra-peritoneal pentobarbital (45mg/kg). KA injection was repeated in all rats 2 days later but with concomitant bilateral, continuous, STN stimulation (frequency: 130Hz; pulse width: 60usec). Video-EEG recording was similarly performed for 1 hour & epileptiform activity terminated with pentobarbital. EEG recordings were blindly analysed & the amount of epileptiform activity compared within each rat (KA with/without STN stimulation) using paired t-tests.
RESULTS: Total KA-induced seizure activity was significantly reduced (mean 47.34% vs 69.51%, p=0.007) with STN stimulation. Though secondarily generalized seizures were significantly reduced (27.35% vs 47.85%, p=0.005), the amount of focal (hippocampal) seizures was not lowered with STN stimulation. Most animals show a prolonged latency to onset of initial seizure with concomitant STN stimulation.
CONCLUSIONS: Bilateral, continuous, high-frequency STN stimulation lowers seizure activity in an acute animal model of kainate-induced seizures.
Support: Research Proposal Committee, The Cleveland Clinic Foundation.