Effects And Mechanisms Of Spinal Cord Stimulation-Induced Vasodilation With Different Frequencies On Lower Limbs

Spinal cord stimulation (SCS) delivers electrical impulses to different spinal segments via implanted electrodes. It has been used to treat selected patients suffer from peripheral arterial diseases, e.g. peripheral arterial occlusive disease. Over fifty thousand patients receive SCS every year and the overall success rate reaches 80%. SCS at lumbar spinal segments L2-L3 can increase the blood flow of lower extremities and is usually the last sort after failure of surgical and pharmacological interventions. The underlying mechanism of vasodilation induced by SCS is not fully understood. The current study divided three parts: (1) To determine whether SCS at high frequency (500 Hz) will affect the threshold, increase vasodilation and decrease vascular resistance compared with lower frequency (50 Hz). (2) To test whether TRPV1 and CGRP are involved in SCS-induced vasodilation. (3) To investigate whether ATP-activated and calcium-activated potassium ion channel plays a role in the SCS mechanism. Our results showed that (1) High frequency of SCS significantly increased vasodilation but did not affect the threshold. (2) The effect of high frequency SCS was via activation of transient receptor potential vanilloid-1 (TRPV1) and release of calcitonin gene related peptide, which was the same as lower frequency SCS. (3) ATP-activated and calcium-activated potassium ion channel inhibitor significantly decreased SCS induced vasodilation, implied that these two ion channels played important roles in SCS induced vasodilation. Our study provided novel experimental information of the possible mechanism of SCS induced vasodilation, which also provided the certain theories to spread SCS in treatment of PVD.