Sympathetic responses to repetitive trans-spinal magnetic stimulation.
OBJECTIVE
Electromagnetic fields have been administered, with mixed success, in order to treat a variety of ailments. Transcranial magnetic stimulation (TMS) elicits brief changes in peripheral sympathetic nervous system (SNS) activity. The purpose of this study was to explore the utility of repetitive trans-spinal magnetic stimulation (rTSMS) for acute and prolonged modulation of SNS in adult humans.


METHODS
23 healthy men and women were randomly assigned to receive either rTSMS (figure-eight coil aligned with the sixth and seventh cervical vertebrae; 10 Hz; n = 14, at 100% intensity of stimulator output) or sham stimulation (n = 13).


RESULTS
Compared with sham, rTSMS did not affect skeletal muscle SNS activity (via microneurography) during the 60-s or 10-min period following stimulation. rTSMS also had no effect on R-to-R interval (RR(int)) and standard deviation of RR(int) (a marker of heart rate variability), blood pressure or plasma concentrations of norepinephrine, epinephrine, insulin and glucose (condition/time interaction, all P > 0.10).


CONCLUSIONS
These data suggest that rTSMS does not influence SNS in adults. While rTSMS represents a novel application of TMS technology, further study and perhaps modification of the technique is required before use in clinical studies of peripheral SNS function.
Department of Health and Exercise Science, Colorado State University, 205E Moby B-Complex, Fort Collins, CO 80523-1582, USA.
Roger J
RJ
Paxton
Matthew P
MP
Malcolm
Sean A
SA
Newsom
Jennifer C
JC
Richards
Grant M
GM
Rynn
Christopher
C
Bell
D000328:Adult; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D055909:Magnetic Field Therapy / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*