Stroke, Vol 22, 1059-1063, Copyright © 1991 by American Heart Association
Disruption of the blood-brain barrier in open and closed cranial window preparations in rats
WG Mayhan
Department of Physiology and Biophysics, University of Nebraska Medical Center, Omaha 68198-4575.
The goal of this study was to determine whether the severity of disruption
of the blood-brain barrier during acute hypertension is similar in open and
closed cranial window preparations. Intravital fluorescent microscopy and
fluorescein-labeled albumin were used to evaluate disruption of the
blood-brain barrier under control conditions and during acute arterial
hypertension in 10 rats equipped with an open cranial window and in six
rats equipped with a closed cranial window. Permeability of the blood-brain
barrier was quantified by calculating the clearance of fluorescein-labeled
albumin and by counting the number of microvascular leaky sites under
control conditions and during acute hypertension. Pressure in cerebral
venules and intracranial pressure were measured in rats equipped with an
open cranial window and a closed cranial window, respectively, under
control conditions and during acute hypertension. In rats equipped with an
open cranial window, arterial pressure increased from 118 +/- 6 to 189 +/-
3 mm Hg (mean +/- SEM) and pial venous pressure increased from 7 +/- 1 to
22 +/- 3 mm Hg during acute hypertension induced with 30 micrograms/kg/min
phenylephrine for 5 minutes. In addition, the clearance of fluorescent
albumin increased from 0.11 +/- 0.03 to 1.2 +/- 0.4 ml/sec x 10(-6) and the
number of microvascular leaky sites increased from 0 to 25 +/- 1 during
phenylephrine infusion. In rats equipped with a closed cranial window,
arterial pressure increased from 122 +/- 5 to 187 +/- 7 mm Hg and
intracranial pressure increased from 3 +/- 1 to 12 +/- 1 mm Hg during the
intravenous infusion of 30 micrograms/kg/min phenylephrine for 5
minutes.(ABSTRACT TRUNCATED AT 250 WORDS)