Document Detail

Augmentation of endothelium-independent flow constriction in pial arteries at high intravascular pressures.
MedLine Citation:
PMID:  2045168     Owner:  NLM     Status:  MEDLINE    
The effects of an increase in intraluminal pressure and flow on the diameter and active smooth muscle tone of pial arteries was studied in perfused segments. Resistance arteries (approximately 250-300 microns i.d.) were perfused under controlled pressure and flow conditions, and changes in arterial diameter registered with an automated video device. In any particular segment, diameter measurements were normalized to that observed at 5 mm Hg. Changes in active wall force were determined by relating the observed diameter under a particular set of conditions to the diameter at the same intramural pressure when smooth muscle tone was inhibited (calcium-free physiological saline solution) and to the diameter when smooth muscle cells were activated close to maximum (KCl; 89 mM). At 60 mm Hg, the diameter decrease of 21% in the absence of flow represented stretch-induced tone. No additional changes in diameter were encountered with a flow of 20 microliters/min. Diameter decreased a further 7% at 100 microliters/min. When intraluminal pressure was 90 mm Hg, diameter decreased 39% without flow. Additional constriction of 10% and 19% occurred at flows of 20 and 100 microliters/min, respectively. At the higher pressure, the vasoconstriction occasioned by flow was significantly greater than that at the lower pressure. After endothelium inactivation by passing hypo-osmotic Krebs' solution followed by air through the segment, mean diameter was less at each combination of pressure and flow, although this difference did not reach statistical significance. The diameter reductions to increases in pressure from 60 to 90 mm Hg and to flow at 40 microliters/min were not altered by endothelium inactivation.(ABSTRACT TRUNCATED AT 250 WORDS)
J L Garcia-Roldan; J A Bevan
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Hypertension     Volume:  17     ISSN:  0194-911X     ISO Abbreviation:  Hypertension     Publication Date:  1991 Jun 
Date Detail:
Created Date:  1991-07-12     Completed Date:  1991-07-12     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  870-4     Citation Subset:  IM    
Department of Pharmacology, University of Vermont, College of Medicine, Burlington 05405.
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MeSH Terms
Blood Pressure*
Cerebral Arteries / physiology*
Endothelium, Vascular / physiology*
Muscle, Smooth, Vascular / physiology
Pia Mater / blood supply*
Grant Support

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