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

This study examined whether spinal cord stimulation (SCS) at intensities be low motor threshold (MT) produces cutaneous vasodilation through sympatheti c inhibition and/or antidromic activation of sensory fibers. SCS was applie d 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 vasod ilation was not attenuated by hexamethonium, an autonomic ganglion blocking agent, but was abolished by CGRP-(8-37), an antagonist of the calcitonin g ene-related peptide (CGRP) receptor. We concluded that SCS-induced vasodila tion under the conditions of this study was mediated by peripheral release of CGRP via antidromic activation of sensory fibers. (C) 2001 Elsevier Scie nce B.V. All rights reserved.