Article
Expression of c-fos after deep brain stimulation of the pedunculopontine tegmental nucleus in the rat 6-hydroxydopamine Parkinson model
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Published: | April 28, 2011 |
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Objective: Deep brain stimulation (DBS) is increasingly used to alleviate motor dysfunction in Parkinson´s disease (PD). The pedunculopontine tegmental nucleus (PPTg) may be a potential target for DBS in PD patients with severe postural instability or freezing, whereby 25 Hz stimulation is considered more effective than 130 Hz stimulation. Here, we evaluated the expression of c-fos after 25 Hz and 130 Hz DBS of the PPTg in the rat 6-hydroxydopamine (6-OHDA) Parkinson model.
Methods: Anesthetized male Sprague Dawley rats with unilateral 6-OHDA-induced nigrostriatal lesions were stimulated with 25 Hz, 130 Hz, or 0 Hz sham-stimulation (each group n=6) for four hours by electrodes implanted into the ipsilateral PPTg. Thereafter, the distribution and number of neurons expressing the immediate early gene c-fos, a marker for acute neuronal activity, was assessed.
Results: DBS of the PPTg induced strong ipsilateral c-fos expression at the stimulation site, with 25 Hz having a more marked impact than 130 Hz (ANOVA with post-hoc Tukey test p<0.05). Additionally, c-fos was strongly expressed in the central gray matter. In the dorsal region, expression was stronger after 25 Hz stimulation (ANOVA with post-hoc Tukey test p<0.05), while in the medial and ventral regions, there were no differences between 25 Hz and 130 Hz stimulation. Expression in the basal ganglia was negligible.
Conclusions: In the rat 6-OHDA PD model, stimulation of the PPTg did not affect c-fos expression in the basal ganglia, but had a strong impact on other functional circuitries. PPN stimulation in humans might therefore also have an impact on other systems than the motor system.