Time- and pressure-dependent changes in blood-brain barrier permeability after temporary middle cerebral artery occlusion in rats.
After 180 min of temporary middle cerebral artery occlusion in rats, the affect of phenylephrine-induced hypertension on blood-brain barrier permeability was assessed. One of the following blood-pressure regimens was maintained during either a 30- or 120-min period of reperfusion: (a) 30/Norm, 30 min of normotensive reperfusion was allowed; (b) 30/HTN, mean arterial blood pressure was increased by 35 mm Hg during 30 min of reperfusion; (c) 120/Norm, 120 min of normotensive reperfusion was allowed; or (d) 120/HTN, mean arterial blood pressure was increased by 35 mm Hg during 120 min of reperfusion. Evans blue (30 mg/kg) was given, and brains were analyzed for Evans blue by spectrophotometry. Evans blue (microgram/g brain tissue, mean +/- SD) was greater (P less than 0.05) in both hypertensive groups versus their time matched normotensive groups (30/HTN: 80 +/- 16 versus 18 +/- 6 in the 30/Norm group; 120/HTN: 17 +/- 6 versus 8 +/- 3 in the 120/Norm group). In addition, Evans blue was greater (P less than 0.05) in both 30-min groups versus their pressure matched 120-min groups (30/Norm: 18 +/- 6 versus 8 +/- 3 in the 120/Norm group; 30/HTN: 80 +/- 16 versus 17 +/- 6 in the 120/HTN group). The data are consistent with previous studies which have demonstrated an opening of the blood-brain barrier at the onset of reperfusion. In addition, the data support a hypothesis that changes in blood-brain barrier permeability are more sensitive to hypertension in the early period of reperfusion.
Cole
D J
DJ
Department of Anesthesiology, Loma Linda University, CA 92354.
Matsumura
J S
JS
Drummond
J C
JC
Schultz
R L
RL
Wong
M H
MH
D000818:Animals; D001157:Arterial Occlusive Diseases / Q000473:pathology / Q000503:physiopathology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000502:physiology*; D001921:Brain / Q000473:pathology; D001929:Brain Edema / Q000473:pathology / Q000503:physiopathology; D002545:Brain Ischemia / Q000473:pathology / Q000503:physiopathology; D002536:Cerebral Arteries / Q000473:pathology / Q000503:physiopathology*; D005070:Evans Blue; D006863:Hydrogen-Ion Concentration; D006973:Hypertension / Q000503:physiopathology; D007811:Lanthanum; D008297:Male; D010539:Permeability; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D015424:Reperfusion
D010656:Phenylephrine; D005070:Evans Blue; D007811:Lanthanum