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.
- Antidromic afferent activation
- Calcitonin gene-related peptide
- Skin vasodilation
- Spinal cord stimulation
- Sympathetic inhibition