TY - JOUR
T1 - Cutaneous vasodilation during dorsal column stimulation is mediated by dorsal roots and CGRP
AU - Groom, John E.
AU - Foreman, Robert D.
AU - Chandler, Margaret J.
AU - Barron, Kirk W.
PY - 1997/2/1
Y1 - 1997/2/1
N2 - Dorsal column stimulation (DCS) is used clinically to provide pain relief from peripheral vascular disease and has the benefit of increasing cutaneous blood flow to the affected lower extremities. The purpose of this study was to examine the role of dorsal roots, calcitonin gene-related peptide (CGRP), and substance P in the cutaneous vasodilation induced by DCS. Male rats were anesthetized with pentobarbital sodium (60 mg/kg ip). A unipolar ball electrode was placed unilaterally on the spinal cord at the L1-L2 spinal segment. Blood flow was recorded in each hindpaw foot pad with laser Doppler flowmeters. Blood flow responses were assessed during 1 min of DCS (either 0.2 mA subdural or 0.6 mA epidural at 50 Hz, 0.2-ms pulse duration). Dorsal rhizotomy of L3-L5 (n = 5) abolished the cutaneous vasodilation to subdural DCS, whereas removal of T10-T12 (n = 5) and T13-L2 dorsal roots (n = 5) did not attenuate the DCS-induced vasodilation. The CGRP antagonist, CGRP-(837) (2.6 mg/kg iv, n = 7), eliminated the epidural DCS-induced vasodilation, whereas the substance P receptor antagonist, CP-96345 (1 mg/kg iv, n = 6), had no effect. In summary, L3-L5 dorsal roots and CGRP are essential for the DCS-induced vasodilation. We propose that DCS antidromitally activates afferent fibers in the dorsal roots, thus causing peripheral release of CGRP, which produces cutaneous vasodilation.
AB - Dorsal column stimulation (DCS) is used clinically to provide pain relief from peripheral vascular disease and has the benefit of increasing cutaneous blood flow to the affected lower extremities. The purpose of this study was to examine the role of dorsal roots, calcitonin gene-related peptide (CGRP), and substance P in the cutaneous vasodilation induced by DCS. Male rats were anesthetized with pentobarbital sodium (60 mg/kg ip). A unipolar ball electrode was placed unilaterally on the spinal cord at the L1-L2 spinal segment. Blood flow was recorded in each hindpaw foot pad with laser Doppler flowmeters. Blood flow responses were assessed during 1 min of DCS (either 0.2 mA subdural or 0.6 mA epidural at 50 Hz, 0.2-ms pulse duration). Dorsal rhizotomy of L3-L5 (n = 5) abolished the cutaneous vasodilation to subdural DCS, whereas removal of T10-T12 (n = 5) and T13-L2 dorsal roots (n = 5) did not attenuate the DCS-induced vasodilation. The CGRP antagonist, CGRP-(837) (2.6 mg/kg iv, n = 7), eliminated the epidural DCS-induced vasodilation, whereas the substance P receptor antagonist, CP-96345 (1 mg/kg iv, n = 6), had no effect. In summary, L3-L5 dorsal roots and CGRP are essential for the DCS-induced vasodilation. We propose that DCS antidromitally activates afferent fibers in the dorsal roots, thus causing peripheral release of CGRP, which produces cutaneous vasodilation.
KW - antidromic vasodilation
KW - calcitonin gene- related peptide
KW - cutaneous blood flow
KW - laser Doppler flowmetry
KW - microcirculation
KW - skin vasodilation
KW - spinal cord
KW - spinal cord stimulation
KW - substance P
UR - http://www.scopus.com/inward/record.url?scp=0030938912&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.1997.272.2.h950
DO - 10.1152/ajpheart.1997.272.2.h950
M3 - Article
C2 - 9124459
AN - SCOPUS:33750882725
VL - 272
SP - H950-H957
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
SN - 0363-6135
IS - 2 41-2
ER -