Calcitonin gene-related peptide and substance P contribute to reduced blood pressure in sympathectomized rats.
CGRP and substance P (SP) are produced in dorsal root ganglia (DRG) sensory neurons and modulate vascular tone. Sympathetic and sensory nerves compete for NGF, a potent stimulator of CGRP and SP, and it has been suggested that sympathetic hyperinnervation in spontaneously hypertensive rats may reduce the availability of NGF to sensory nerves, thus reducing CGRP and SP. The purpose of this study was to determine whether destruction of peripheral sympathetic nerves in normal rats would increase the availability of NGF for sensory neurons and enhance expression of CGRP and SP. Sympathectomy was produced in rats by guanethidine sulfate administration. Control rats received saline. Sympathectomized rats displayed reductions in blood pressure (BP) and atria norepinephrine levels, whereas NGF levels in the DRG, spleen, and ventricles were increased. Sympathectomy also enhanced CGRP and SP mRNA and peptide content in DRG. Administration of CGRP and SP receptor antagonists increased the BP in sympathectomized rats but not in the controls. Thus sympathectomy enhances sensory neuron CGRP and SP expression that contributes to the BP reduction.
Supowit
S C
SC
Department of Medicine, Texas A and M University System Health Science Center College of Medicine, Temple, TX 76504, USA. ssupowit@swmail.sw.org
Ethridge
R T
RT
Zhao
H
H
Katki
K A
KA
Dipette
D J
DJ
D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D015740:Calcitonin Gene-Related Peptide / Q000235:genetics / Q000378:metabolism*; D002395:Catecholamines / Q000378:metabolism; D005727:Ganglia, Spinal / Q000502:physiology*; D006145:Guanethidine; D006325:Heart Atria / Q000378:metabolism; D006352:Heart Ventricles / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000378:metabolism; D020932:Nerve Growth Factor / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013154:Spleen / Q000378:metabolism; D013373:Substance P / Q000235:genetics / Q000378:metabolism*; D013563:Sympathectomy, Chemical; D013565:Sympatholytics
D002395:Catecholamines; D012333:RNA, Messenger; D013565:Sympatholytics; D013373:Substance P; D020932:Nerve Growth Factor; D015740:Calcitonin Gene-Related Peptide; D006145:Guanethidine