Document Detail

Mechanisms of protection of the blood-brain barrier during acute hypertension in chronically hypertensive rats.
MedLine Citation:
PMID:  3596775     Owner:  NLM     Status:  MEDLINE    
Spontaneously hypertensive rats are less susceptible than normotensive rats to disruption of the blood-brain barrier during acute hypertension. The purpose of this study was to examine mechanisms that protect the blood-brain barrier from disruption in chronically hypertensive rats during acute hypertension. Normotensive Wistar-Kyoto rats (WKY) and stroke-prone spontaneously hypertensive rats (SHRSP) were studied using intravital fluorescent microscopy and fluorescein-labeled dextran. Disruption of the blood-brain barrier was characterized by the appearance of microvascular leaky sites and quantitated by the clearance of fluorescein-labeled dextran. We measured pressure (servo null) in pial arterioles and venules 40 to 60 micron in diameter. In WKY, acute, phenylephrine-induced hypertension increased pial arteriolar pressure by 47 +/- 7 mm Hg (mean +/- SE) and pial venous pressure by 20 +/- 2 mm Hg. Leaky sites increased from 0 to 28 +/- 2. In SHRSP, acute hypertension increased pial arteriolar pressure 44 +/- 8 mm Hg, but pial venous pressure increased only 6 +/- 1 mm Hg and leaky sites increased from 0 to only 6 +/- 1. All leaky sites were venular. In another group of WKY and SHRSP, we increased pial venous pressure passively with a neck cuff. In WKY, venous pressure increased by 22 +/- 2 mm Hg, and leaky sites increased from 0 to 23 +/- 2. In SHRSP, venous pressure increased by 19 +/- 1 mm Hg, and leaky sites increased from 0 to 24 +/- 2. Thus, when venous pressure is increased to the same level in WKY and SHRSP, disruption of the blood-brain barrier is similar. We conclude that protection of the blood-brain barrier during acute hypertension in SHRSP is related to attenuation of increases in pial venous pressure, not pial arteriolar pressure, and the blood-brain barrier in venules of SHRSP probably is not inherently resistant to disruption.
W G Mayhan; F M Faraci; D D Heistad
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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:  Hypertension     Volume:  9     ISSN:  0194-911X     ISO Abbreviation:  Hypertension     Publication Date:  1987 Jun 
Date Detail:
Created Date:  1987-08-05     Completed Date:  1987-08-05     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  III101-5     Citation Subset:  IM    
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MeSH Terms
Acute Disease
Aorta / physiopathology
Blood Pressure
Blood-Brain Barrier*
Capillary Permeability
Constriction, Pathologic
Hypertension / physiopathology*
Neck / blood supply
Pia Mater / blood supply
Rats, Inbred SHR
Rats, Inbred WKY
Venous Pressure
Venules / metabolism
Grant Support

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

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