M.Sc Thesis

M.Sc StudentShaul Uri
SubjectEffect of Magnetic Stimulation, Frequency and Number of
Treatments, on the Monoaminergic System in Human
Neuroblastoma SH-SY5Y Cells:
Implications to the antidep...
DepartmentDepartment of Medicine
Supervisors PROFESSOR EMERITUS Dorit Ben-Shachar


Transcranial magnetic stimulation (TMS), which is produced by strong non-static magnetic fields, is a non-invasive means to stimulate the cerebral cortex. Studies from recent years show that TMS affects mood in healthy subjects and improves depressive symptoms in patients with major depression (MD). However, the relationship between the clinical efficacy of TMS and stimulation parameters is still obscure. In the present study we have investigated the effects of different stimulation frequencies and number of treatments, on catecholamines turnover in SH-SY5Y cell cultures. A single session of magnetic stimulation (1.7T) caused a significant decrease in intracellular dopamine and L-DOPA and in NE release at a rate of 3Hz for 10 sec but increased NE release at a rate of 9Hz. These alterations were associated with a reduction (47.8%) or an increase (148%) in tyrosine hydroxylase (TH) activity after 3 and 9Hz magnetic stimulation, respectively. The latter may be related to the known sensitivity of TH to neuronal firing rates and NE concentrations. Higher stimulation frequencies (15, 20, 45Hz) had no effect on catecholamines metabolism. Unlike 3Hz acute treatment chronic treatment (3Hz, 11 sessions, for 4 days) had no effect on monoamines while TH activity was increased by 54.5% with no change in its protein level. The results of the present study demonstrate that frequency and treatment duration of the magnetic stimulation are important factors in affecting catecholamines, which play a crucial role in MD, and thus should be considered when using rTMS as a clinical tool for mood disorders.