Document Detail


Direct and reflexive effects of nitric oxide synthase inhibition on blood pressure.
MedLine Citation:
PMID:  17965289     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Direct effects of vasoactive substances on blood pressure can be examined in individuals with tetraplegia due to disruption of descending spinal pathways to sympathetic preganglionic neurons, as cervical lesions interfere with baroreceptor reflex buffering of sympathetic outflow. In this study, we assessed effects of the nitric oxide synthase inhibitor nitro-L-arginine methyl ester (L-NAME) on mean arterial pressure, heart rate, and plasma norepinephrine concentrations in individuals with tetraplegia vs. effects shown in a neurologically intact control group. Seven individuals with tetraplegia and seven age-matched controls received, on separate visits and in the following order, placebo (30 ml normal saline) and 0.5, 1, 2, and 4 mg/kg L-NAME intravenously over 60 min. Supine hemodynamic data were collected, and blood was sampled at the end of each infusion and at 120, 180, and 240 min thereafter. L-NAME increased mean arterial pressure, and the relative increase was greater in the tetraplegia group than in the control group. Heart rate was reduced after L-NAME administration in both groups. L-NAME decreased plasma norepinephrine in the control group but not in the group with tetraplegia. These findings suggest that reflexive sympathoinhibition normally buffers the pressor response to nitric oxide synthase inhibition, an effect that is not evident in individuals with tetraplegia as a result of decentralized sympathetic vasomotor control.
Authors:
Jill M Wecht; Joseph P Weir; David S Goldstein; Annmarie Krothe-Petroff; Ann M Spungen; Courtney Holmes; William A Bauman
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Publication Detail:
Type:  Controlled Clinical Trial; Journal Article; Research Support, N.I.H., Intramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2007-10-26
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  294     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2008 Jan 
Date Detail:
Created Date:  2008-01-14     Completed Date:  2008-02-28     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H190-7     Citation Subset:  IM    
Affiliation:
Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, 130 West Kingsbridge Rd., Bronx, NY 10468, USA. jm.wecht@va.gov
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MeSH Terms
Descriptor/Qualifier:
Adult
Baroreflex / drug effects*
Blood Pressure / drug effects*
Dose-Response Relationship, Drug
Enzyme Inhibitors / administration & dosage*
Heart Rate / drug effects
Humans
Infusions, Intravenous
Middle Aged
NG-Nitroarginine Methyl Ester / administration & dosage*
Neural Inhibition / drug effects*
Nitric Oxide Synthase / antagonists & inhibitors*,  metabolism
Norepinephrine / blood
Quadriplegia / blood,  enzymology,  physiopathology*
Sympathetic Nervous System / drug effects*,  physiopathology
Time Factors
Chemical
Reg. No./Substance:
0/Enzyme Inhibitors; 50903-99-6/NG-Nitroarginine Methyl Ester; 51-41-2/Norepinephrine; EC 1.14.13.39/Nitric Oxide Synthase

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


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