Document Detail

Baroreceptor-heart rate reflex function before and after surgical reversal of two-kidney, one-clip hypertension in the rat.
MedLine Citation:
PMID:  2188749     Owner:  NLM     Status:  MEDLINE    
Baroreflex function was studied in conscious early phase (less than 6 weeks) two-kidney, one-clip hypertensive rats before and 24 hours after surgical reversal of hypertension by removal of the constricting renal artery clip or after pharmacological reduction of blood pressure by an infusion of hydralazine or captopril. A normotensive sham-clipped group was included. Another group of two-kidney, one-clip rats was studied 3 weeks after unclipping. Baroreflex sensitivity, as assessed by the steady-state method using a graded phenylephrine infusion, mean arterial pressure, and heart rate were measured preoperatively and at 24 hours postoperatively. Two-kidney, one-clip rats were significantly hypertensive preoperatively compared with control (mean arterial pressure, 183 +/- 4 vs. 106 +/- 2 mm Hg, p less than 0.001), heart rate was similar (420 +/- 9 vs. 401 +/- 9 beats/min, p greater than 0.05), and baroreflex sensitivity was significantly reduced (0.76 +/- 0.07 vs. 1.50 +/- 0.20 msec/mm Hg; p less than 0.001). There was a minimal change in heart rate despite the fall in mean arterial pressure in all hypertensive groups, indicating resetting of the baroreflexes. At 24 hours after the operation, baroreflex sensitivity was unchanged in all groups compared with the preoperative value. By 3 weeks, baroreflex sensitivity was significantly greater than in the hypertensive two-kidney, one-clip rats before the operation and 24 hours after they were unclipped, but not compared with normotensive sham-clipped rats. Thus, although resetting occurs within 24 hours, whatever the method of blood pressure reduction, baroreflex sensitivity remains impaired at this time.(ABSTRACT TRUNCATED AT 250 WORDS)
M E Edmunds; G I Russell; P R Burton; J D Swales
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Circulation research     Volume:  66     ISSN:  0009-7330     ISO Abbreviation:  Circ. Res.     Publication Date:  1990 Jun 
Date Detail:
Created Date:  1990-07-05     Completed Date:  1990-07-05     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0047103     Medline TA:  Circ Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1673-80     Citation Subset:  IM    
Department of Medicine, University of Leicester, UK.
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MeSH Terms
Blood Pressure / drug effects
Captopril / pharmacology
Heart Rate*
Hydralazine / pharmacology
Hypertension, Renovascular / physiopathology*
Pressoreceptors / physiology*
Rats, Inbred Strains
Reflex / physiology*
Time Factors
Reg. No./Substance:
62571-86-2/Captopril; 86-54-4/Hydralazine

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

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