Effekt der Tiefenhirnstimulation des Nucleus Subthalamicus auf die Anfallslänge und -frequenz im WAG/Rij- und im Kindling-Modell der Ratte

A modulating role of the basal ganglia on seizure activity in generalised epilepsy, especially by inhibition of the substantia nigra pars reticulata (SNpr) and subsequent disinhibition of the colliculus superior, has been reported in several studies . Because of its compact spatial extension the STN is, in contrast to the SNpr itself, a practicable aim for surgical intervention through local high-frequency stimulation (HFS) resulting in an inhibition of the SNpr by interfering with the excitatory subthalamico-nigral pathway. An effect evoked by retrograde interaction with cortico-subthalamic pathways is also discussed. Deep brain stimulation is already in clinical use for Parkinson’s disease and tremors. Pilot studies in difficult to treat epilepsy patients have been partly successful initiated In the present study the effect of bilateral HFS of the STN on seizure activity was investigated in 10 rats of the WAG/Rij strain, expressing absence seizures well defined by EEG and clinically. Using the stimulation paradigms as previously described by Vercueil et al. in another rat strain (GEARS) adapted to our demands (130 Hz, single impulse-duration of 60 µs, monophasic, 20% below motor threshold), seizure triggered acute (5 s) and continuous bilateral (10 min) HFS of the STN were used. Effects were evaluated by seizure-frequency and cumulative seizure duration during chronic stimulation (CS) compared to pre stimulation (PS) and after stimulation (AS) periods (each 10 min) In rats with well placed electrodes (fig. 2) acute seizure triggered stimulation resulted in termination of some but never all absences .