Document Detail


Modulation of the carotid baroreceptor reflex by substance P in the nucleus tractus solitarius.
MedLine Citation:
PMID:  10789685     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Previous studies have shown that administration of substance P (SP) into the nucleus tractus solitarius (NTS) can evoke a depressor response similar to that produced by activation of the arterial baroreceptors. In addition, some studies have suggested that SP increases the reflex responses to activation of baroreceptor input. The present study was performed to determine the effects of SP on the carotid sinus baroreceptor reflex at the level of the NTS by examining the effects of both exogenous SP microinjected into different rostrocaudal locations in the NTS and blockade of the effects of endogenous SP, through the microinjection of a substance P antagonist (SPa; [D-Pro, D-Trp]-substance P). Changes in pressure in an isolated carotid sinus in anesthetized dogs were used to evoke baroreflex changes in arterial blood pressure (BP) before and after microinjection of SP (0.5 microM) or SPa (10 microM) into barosensitive regions of the NTS. Microinjection of SP or its antagonist did not alter baseline, resting BP but did produce significant changes in baroreflex sensitivity. Microinjection of SP into different rostrocaudal regions of the NTS produced different responses, with rostral and caudal NTS microinjections producing significant increases in sensitivity. No effects on baroreflex sensitivity were obtained in response to SP microinjections into the intermediate NTS. Unlike SP, microinjection of the SPa significantly decreased baroreflex sensitivity at all rostrocaudal levels of the NTS. These data demonstrated that SP has the capability to modulate the carotid baroreflex at the level of the NTS and support a physiological role for endogenously released SP.
Authors:
J L Seagard; C Dean; F A Hopp
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of the autonomic nervous system     Volume:  78     ISSN:  0165-1838     ISO Abbreviation:  J. Auton. Nerv. Syst.     Publication Date:  2000 Jan 
Date Detail:
Created Date:  2000-06-30     Completed Date:  2000-06-30     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8003419     Medline TA:  J Auton Nerv Syst     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  77-85     Citation Subset:  IM    
Affiliation:
Zablocki Department of Veterans Affairs Medical Center, and Medical College of Wisconsin, Milwaukee 53295, USA. jseagard@mcw.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Baroreflex / drug effects*,  physiology*
Blood Pressure / drug effects,  physiology
Carotid Sinus / cytology,  physiology*
Dogs
Microinjections
Neurons / cytology,  drug effects,  metabolism
Pressoreceptors / cytology,  physiology*
Solitary Nucleus / cytology*,  drug effects*,  metabolism*
Substance P / antagonists & inhibitors*,  metabolism*
Grant Support
ID/Acronym/Agency:
HL55490/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
33507-63-0/Substance P

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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