Brain lipid changes after repetitive transcranial magnetic stimulation: potential links to therapeutic effects?
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Repetitive transcranial magnetic stimulation (rTMS) is increasingly used in the management of neurologic disorders such as depression and chronic pain, but little is known about how it could affect brain lipids, which play important roles in membrane structure and cellular functions. The present study was carried out to examine the effects of rTMS on brain lipids at the individual molecular species level using the novel technique of lipidomics. Rats were subjected to high frequency (15 Hz) stimulation of the left hemisphere with different intensities and pulses of rTMS. The prefrontal cortex, hippocampus and striatum were harvested 1 week after rTMS and lipid profiles analyzed by tandem mass spectrometry. rTMS resulted in changes mainly in the prefrontal cortex. There were significant alterations in plasmalogen phosphatidylethanolamines, phosphatidylcholines, and increases in sulfated galactosylceramides or sulfatides. Plasmalogen species with long chain polyunsaturated fatty acids (PUFAs) showed decrease in abundance together with corresponding increase in lysophospholipid species suggesting endogenous release of long chain fatty acids such as docosahexaenoic acid (DHA) in brain tissue. The hippocampus showed no significant changes, whilst changes in the striatum were often opposite to that of the prefrontal cortex. It is postulated that changes in brain lipids may underlie some of the clinical effects of rTMS.
KeywordsTranscranial magnetic stimulation Sulfatide Plasmalogens Lipids Polyunsaturated fatty acids Depression Pain Alzheimer’s disease Frontal cortex
This work was supported by the National Medical Research Council (R-181-000-125-275 and R-183-000-224-213), National Research Foundation (CRP Award No. 2007-04), Biomedical Research Council (R-183-000-211-305) and the Academic Research Fund (R-183-000-160-112). There are no conflicts of interest.
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