Document Detail


Impaired autoregulation in an experimental model of chronic cerebral hypoperfusion in rats.
MedLine Citation:
PMID:  8711809     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND AND PURPOSE: To verify the hypothesis that impaired autoregulation may contribute to cerebral swelling or hemorrhage after a sudden recovery of perfusion pressure, we studied the chronic effects of cerebral hypoperfusion on the autoregulatory responses of the pial arterioles in situ. METHODS: Eight to 12 weeks after a carotid-jugular fistula was created in rats, experiments were performed under alpha-chloralose and urethane anesthesia. Regional cerebral blood flow (rCBF) was determined by the hydrogen clearance method, and carotid pressure was measured. Using a closed cranial window, we determined the autoregulatory responses of the arterioles (30 to 50 microns) to both hypertension induced by norepinephrine and sudden fistula closure at various mean arterial pressures (MAPs). RESULTS: rCBF on the fistula side was reduced by 27%. Carotid pressure was significantly lower than normal but was immediately increased by fistula closure. The pial arterioles showed marked elongation and enlargement. During induced hypertension, the arterioles in the fistula group started to dilate at an MAP lower than that of the control group (130 versus 180 mm Hg, respectively). The arterioles constricted when the fistula was occluded at normal MAP. However, when the fistula was occluded at an MAP higher than 130 mm Hg, the vessels dilated. CONCLUSIONS: It was demonstrated that (1) chronic hypoperfusion induced impairment of the upper limit of autoregulation and (2) sudden fistula closure under hypertensive conditions caused vasodilation of the arterioles. These findings suggest that rapid restoration of perfusion pressure is possibly followed by a pressure breakthrough phenomenon in a chronically hypoperfused cerebrovasculature.
Authors:
K Irikura; S Morii; Y Miyasaka; M Yamada; K Tokiwa; K Yada
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Stroke; a journal of cerebral circulation     Volume:  27     ISSN:  0039-2499     ISO Abbreviation:  Stroke     Publication Date:  1996 Aug 
Date Detail:
Created Date:  1996-09-10     Completed Date:  1996-09-10     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0235266     Medline TA:  Stroke     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1399-404     Citation Subset:  IM    
Affiliation:
Department of Neurosurgery, Kitasato University School of Medicine, Kanagawa, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Arteriovenous Fistula / surgery
Brain Ischemia / physiopathology*
Carotid Arteries / physiopathology
Cerebrovascular Circulation / physiology*
Chronic Disease
Disease Models, Animal
Homeostasis / physiology*
Hypercapnia / physiopathology
Hypertension / physiopathology
Hypocapnia / physiopathology
Jugular Veins / physiopathology
Male
Microcirculation / physiology
Pia Mater / blood supply,  physiopathology
Pressure
Rats
Rats, Sprague-Dawley
Regional Blood Flow

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


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