Document Detail

Effect of cerebral perfusion pressure on cerebral cortical microvascular shunting at high intracranial pressure in rats.
MedLine Citation:
PMID:  23204051     Owner:  NLM     Status:  MEDLINE    
BACKGROUND AND PURPOSE: Recently, we showed that decreasing cerebral perfusion pressure (CPP) from 70 mm Hg to 50 mm Hg and 30 mm Hg by increasing intracranial pressure (ICP) with a fluid reservoir induces a transition from capillary (CAP) to microvascular shunt (MVS) flow in the uninjured rat brain. This transition was associated with tissue hypoxia, increased blood-brain barrier (BBB) permeability, and brain edema. Our aim was to determine whether an increase in CPP would attenuate the transition to MVS flow at high ICP.
METHODS: Rats were subjected to progressive, step-wise increases in ICP of up to 60 mm Hg by an artificial cerebrospinal fluid reservoir connected to the cisterna magna. CPP was maintained at 50, 60, 70, or 80 mm Hg by intravenous dopamine infusion. Microvascular red blood cell flow velocity, BBB integrity (fluorescein dye extravasation), and tissue oxygenation (nicotinamide adenine dinucleotide) were measured by in vivo 2-photon laser scanning microscopy. Doppler cortical flux, rectal and cranial temperatures, ICP, arterial blood pressure, and gases were monitored.
RESULTS: The CAP/MVS ratio increased (P<0.05) at higher ICP as CPP was increased from 50 to 80 mm Hg. At an ICP of 30 mm Hg and CPP of 50 mm Hg, the CAP/MVS ratio was 0.6±0.1. At CPP of 60, 70, and 80 mm Hg, the ratio increased to 0.9±0.1, 1.4±0.1, and 1.9±0.1, respectively (mean±SEM; P<0.05). BBB opening and increase of reduced form of nicotinamide adenine dinucleotide occurred at higher ICP as CPP was increased.
CONCLUSIONS: Increasing CPP at high ICP attenuates the transition from CAP to MVS flow, development of tissue hypoxia, and increased BBB permeability.
Denis E Bragin; Rachel C Bush; Edwin M Nemoto
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2012-11-29
Journal Detail:
Title:  Stroke; a journal of cerebral circulation     Volume:  44     ISSN:  1524-4628     ISO Abbreviation:  Stroke     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2012-12-25     Completed Date:  2013-02-18     Revised Date:  2014-01-09    
Medline Journal Info:
Nlm Unique ID:  0235266     Medline TA:  Stroke     Country:  United States    
Other Details:
Languages:  eng     Pagination:  177-81     Citation Subset:  IM    
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MeSH Terms
Blood Flow Velocity / physiology
Blood-Brain Barrier / physiology
Cerebral Cortex / blood supply*,  physiology*
Cerebrovascular Circulation / physiology*
Intracranial Hypertension / physiopathology*
Intracranial Pressure / physiology*
Microcirculation / physiology*
Rats, Sprague-Dawley
Grant Support

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

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