Document Detail


Changes in arterial blood pressure lead to baroreceptor-mediated changes in norepinephrine and 5-hydroxyindoleacetic acid in rat nucleus tractus solitarius.
MedLine Citation:
PMID:  2452247     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Catecholamine and indoleamine metabolism in nucleus tractus solitarius were studied during drug-induced hypertension and hypotension. Urethane-anesthetized normotensive male Sprague-Dawley rats implanted with a 250-mu carbon paste in vivo electrochemical electrode were infused with phenylephrine to raise blood pressure 50 mm Hg. Other animals were given nitroprusside to lower pressure 20 mm Hg. Phenylephrine-induced hypertension was associated with a 30% reduction in the electrochemical peak corresponding to norepinephrine. The electrochemical peak which was identified as 5-hydroxyindoleacetic acid (5-HIAA) was increased 25% with the onset of hypertension and remain elevated after the phenylephrine infusion was stopped. Nitroprusside-induced hypotension resulted in a 20% reduction in the norepinephrine peak during the infusion followed by an additional 10% reduction after the infusion. 5-HIAA concentration did not change during the hypotensive phase but showed a 40% increase after the nitroprusside was stopped as blood pressure rebounded to levels higher than the control period. Direct tissue assays of norepinephrine and 5-HIAA confirmed the electrochemical findings. These experiments were repeated in rats which had undergone sinoaortic denervation. The electrochemical changes in norepinephrine and 5-HIAA associated with hypertension and hypotension were attenuated in these animals indicating that the brain neurotransmitter changes were a consequence of baroreceptor input to the brain. We conclude that 5-HIAA in nucleus tractus solitarius appears to be a marker for elevated blood pressure, whereas norepinephrine falls with either an increase or a decrease in pressure.
Authors:
D Bhaskaran; C R Freed
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of pharmacology and experimental therapeutics     Volume:  245     ISSN:  0022-3565     ISO Abbreviation:  J. Pharmacol. Exp. Ther.     Publication Date:  1988 Apr 
Date Detail:
Created Date:  1988-06-02     Completed Date:  1988-06-02     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0376362     Medline TA:  J Pharmacol Exp Ther     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  356-63     Citation Subset:  IM    
Affiliation:
Department of Medicine, University of Colorado Health Sciences Center, Denver.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Pressure*
Electrochemistry
Hydroxyindoleacetic Acid / metabolism*
Male
Medulla Oblongata / metabolism*
Nitroprusside / pharmacology
Norepinephrine / metabolism*
Pressoreceptors / metabolism*
Rats
Rats, Inbred Strains
Serotonin / metabolism
Grant Support
ID/Acronym/Agency:
HL 00782/HL/NHLBI NIH HHS; HL 30722/HL/NHLBI NIH HHS; NS 18639/NS/NINDS NIH HHS
Chemical
Reg. No./Substance:
15078-28-1/Nitroprusside; 50-67-9/Serotonin; 51-41-2/Norepinephrine; 54-16-0/Hydroxyindoleacetic Acid

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


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