Document Detail


Influence of prolonged baroreflex activation on arterial pressure in angiotensin hypertension.
MedLine Citation:
PMID:  16216987     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Despite recent evidence indicating sustained activation of the baroreflex during chronic infusion of angiotensin II (Ang II), sinoaortic denervation does not exacerbate the severity of the hypertension. Therefore, to determine whether Ang II hypertension is relatively resistant to the blood pressure-lowering effects of the baroreflex, the carotid baroreflex was electrically activated bilaterally for 7 days in 5 dogs both in the presence and absence of a continuous infusion of Ang II (5 ng/kg per minute) producing high physiological plasma levels of the peptide. Under control conditions, basal values for mean arterial pressure (MAP) and plasma norepinephrine concentration (NE) were 93+/-1 mm Hg and 99+/-25 pg/mL, respectively. By day 7 of baroreflex activation, MAP and NE were reduced to 72+/-4 mm Hg (-21+/-3 mm Hg) and 56+/-15 pg/mL, respectively, but PRA was unchanged (control=0.41+/-0.06 ng ANG I/mL per hour). All values returned to basal levels by the end of a 7-day recovery period. After 7 days of Ang II infusion, MAP increased from 93+/-3 to 129+/-3 mm Hg, whereas NE fell from 117+/-15 to 86+/-23 pg/mL. During the next 7 days of baroreflex activation/Ang II infusion, further reductions in NE were not statistically significant, and on the final day of baroreflex activation, the reduction in MAP was only 5+/-1 mm Hg, compared with 21+/-3 mm Hg in the control normotensive state. These findings indicate that long-term baroreflex-mediated reductions in arterial pressure are markedly diminished, but not totally eliminated, in the presence of hypertension produced by chronic infusion of Ang II.
Authors:
Thomas E Lohmeier; Terry M Dwyer; Drew A Hildebrandt; Eric D Irwin; Martin A Rossing; David J Serdar; Robert S Kieval
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, P.H.S.     Date:  2005-10-10
Journal Detail:
Title:  Hypertension     Volume:  46     ISSN:  1524-4563     ISO Abbreviation:  Hypertension     Publication Date:  2005 Nov 
Date Detail:
Created Date:  2005-10-28     Completed Date:  2005-12-29     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1194-200     Citation Subset:  IM    
Affiliation:
Department of Physiology, University of Mississippi Medical Center, Jackson, MS 39216-4505, USA. tlohmeier@physiology.umsmed.edu
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MeSH Terms
Descriptor/Qualifier:
Angiotensin II* / administration & dosage
Animals
Baroreflex*
Blood Pressure*
Blood Proteins / metabolism
Dogs
Drug Administration Schedule
Electrolytes / blood,  urine
Heart Rate
Hematocrit
Hypertension / chemically induced*,  metabolism,  physiopathology*
Male
Neurotransmitter Agents / blood
Norepinephrine / blood
Time Factors
Vasoconstrictor Agents* / administration & dosage
Grant Support
ID/Acronym/Agency:
HL-51971/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Blood Proteins; 0/Electrolytes; 0/Neurotransmitter Agents; 0/Vasoconstrictor Agents; 11128-99-7/Angiotensin II; 51-41-2/Norepinephrine
Comments/Corrections
Comment In:
Hypertension. 2005 Nov;46(5):1095-6   [PMID:  16216986 ]

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


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