Dopamine Release after Repetitive Transcranial Magnetic Stimulation of Motor Cortex in Parkinson's Disease Patients

Background: There is considerable evidence that repetitive transcranial magnetic stimulation (rTMS) of motor cortex exerts significant improvement of motor performance in parkinson's disease (PD) patients in previous studies. Other authors have used brain imaging to show that single session rTMS can transiently increase DA in striatum. Here we try to evaluate whether the rTMS in our study could increase serum dopamine in PD patients or not and correlate it with the clinical scales. Material and Methods: Twenty untreated PD patients with moderate to severe symptoms (Hoehn & Yahr stage III-V 1967). Each patient underwent: Unified Parkinson's Disease Rating Scale (UPDRS), walking speed, keyboard tapping, and Enzyme Immunoassay for the quantitative determination of Dopamine in plasma before and after 6 consecutive sessions of 25 Hz rTMS with 3000 stimuli over the right and left hand and leg motor cortex. Results: There were significant improvement in UPDRS, walking speed, and keytapping after 6 rTMS sessions compared with the base line assessment. Serum dopamine level was significantly elevated after 6 sessions. There was significant correlation between UPDRS and self assessment scale in one hand and serum dopamine level on the other hand. Conclusion: The improvement of motor performance in PD patients after repeated sessions of rTMS could contribute to be related to the elevation of dopamine concentration. (Egypt J. Neurol. Psychiat. Neurosurg., 2007, 44(1): 323-331).