Low intensity spinal cord stimulation may induce cutaneous vasodilation via CGRP release

This study examined whether spinal cord stimulation (SCS) at intensities below motor threshold (MT) produces cutaneous vasodilation through sympathetic inhibition and/or antidromic activation of sensory fibers. SCS was applied to anesthetized rats with stimulus parameters used clinically, i.e. 50 Hz, 0.2 ms and stimulus intensities at 30, 60 or 90% of MT. SCS-induced vasodilation was not attenuated by hexamethonium, an autonomic ganglion blocking agent, but was abolished by CGRP-(8-37), an antagonist of the calcitonin gene-related peptide (CGRP) receptor. We concluded that SCS-induced vasodilation under the conditions of this study was mediated by peripheral release of CGRP via antidromic activation of sensory fibers.