Transcranial Magnetic Stimulation Attenuates Dyskinesias and FosB and c-Fos Expression in a Parkinson's Disease Model.

BACKGROUND/OBJECTIVES: Dopamine replacement therapy for Parkinson's disease (PD) may lead to disabling incontrollable movements known as L-DOPA-induced dyskinesias. Transcranial magnetic stimulation (TMS) has been applied as non-invasive therapy to ameliorate motor symptoms and dyskinesias in PD treatment. Recent studies have shown that TMS-induced motor effects might be related to dopaminergic system modulation. However, the mechanisms underlying these effects of TMS are not fully understood.

OBJECTIVES

To assess the expression of FosB and c-Fos in dopamine-D1 receptor-containing cells of dyskinetic rats and to analyze the effect of TMS on dyskinetic behavior and its histological marker (FosB).

METHODS

We investigated the outcome of TMS on cellular activation, using c-Fos immunoreactivity, on D1 receptor-positive (D1R+) cells into the motor cortex and striatum of dyskinetic ( = 14) and intact rats ( = 14). Additionally, we evaluated the effect of TMS on the dyskinesia global score and its molecular marker, FosB, in the striatum ( = 67).

RESULTS

TMS reduces c-Fos expression in D1R+cells into the motor cortex and striatum. Moreover, TMS treatment attenuated dyskinesias, along with a low stratal FosB expression.

CONCLUSIONS

The current study shows that TMS depressed FosB and c-Fos expression in D1R+ cells of the dorsal striatum and motor cortex, in accordance with previous evidence of its capacity to modulate the dopaminergic system, thus suggesting a mechanism by which TMS may mitigate dyskinesias. Additionally, our observations highlight the potential therapeutic effect of TMS on dyskinesias in a PD model.