Abstract | BACKGROUND AND PURPOSE: This study was designed to investigate the influence of peri- infarct depolarization elicited by occlusion of the middle cerebral artery on the dynamics of the microcirculation. METHODS: The microcirculation in the frontoparietal cortex of 9 rats was visualized in real time through a closed cranial window with the use of laser-scanning confocal fluorescence microscopy combined with intravenous fluorescein isothiocyanate ( FITC)-dextran and FITC-labeled erythrocytes. The direct current potential/electrocorticogram was continuously monitored. Intraluminal focal ischemia was induced for 2 hours in 6 rats anesthetized with halothane and mechanically ventilated. Reperfusion was monitored for 1 hour. Three rats underwent sham operation. Brains were removed 24 hours after occlusion and processed for histology. RESULTS: In control conditions, the velocity of fluorescent erythrocytes through capillaries was 0.51+/-0.19 mm/s (mean+/-SD), and the diameter of the arterioles studied was 33+/-12 microm. Under ischemia, erythrocyte velocity through capillaries was significantly decreased to 0.33+/-0.14 mm/s, while arteriole diameter did not change significantly. During spontaneous peri- infarct depolarizations, arteriole diameter was significantly increased (119+/-23% of baseline), while capillary erythrocyte velocity was further decreased by 14+/-34%. The direction of arteriolar blood flow episodically and transiently reversed during approximately half of the peri- infarct depolarizations. The decrease in capillary erythrocyte velocity was more pronounced (23+/-37%) in these cases. After reperfusion, the microcirculatory variables rapidly returned to baseline. All rats in the ischemic group had infarcts 24 hours after occlusion. CONCLUSIONS: Peri- infarct depolarization has an adverse influence on penumbral microcirculation, reducing capillary perfusion by erythrocytes, despite dilatation of arterioles. These findings suggest that a steal phenomenon contributes to the deleterious effect of these depolarizations.
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Authors | Elisabeth Pinard, Hélène Nallet, Eric T MacKenzie, Jacques Seylaz, Simon Roussel |
Journal | Stroke
(Stroke)
Vol. 33
Issue 2
Pg. 606-12
(Feb 2002)
ISSN: 1524-4628 [Electronic] United States |
PMID | 11823677
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Dextrans
- fluorescein isothiocyanate dextran
- Fluorescein-5-isothiocyanate
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Topics |
- Animals
- Arterioles
(pathology, physiopathology)
- Blood Flow Velocity
- Cerebral Cortex
(blood supply, pathology, physiopathology)
- Cerebral Infarction
(pathology, physiopathology)
- Cerebrovascular Circulation
- Cortical Spreading Depression
- Dextrans
- Electroencephalography
- Erythrocytes
(chemistry, cytology)
- Fluorescein-5-isothiocyanate
(analogs & derivatives, chemistry)
- Infarction, Middle Cerebral Artery
(pathology, physiopathology)
- Male
- Membrane Potentials
- Microcirculation
(pathology, physiopathology)
- Microscopic Angioscopy
- Microscopy, Confocal
- Microscopy, Fluorescence
- Rats
- Rats, Sprague-Dawley
- Vascular Patency
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