The cerebrovascular permeability to protein after bicuculline and amphetamine administration in spontaneously hypertensive rats. Evidence for increased resistance of pressure-induced blood-brain barrier dysfunction.

Hemodynamic and morphometric studies on spontaneously hypertensive rats (SHR) have suggested that the lumen to wall ratio of the resistance vessels is decreased due to hypertrophy of the media. As the tension in the vessel wall increases with the pressure and the radius and decreases with the vessel wall thickness, such vessels would be expected to withstand higher pressure than vessels of normotensive rats (NR) unless local wall defects were present. Bicuculline-induced epileptic activity and amphetamine intoxication, two conditions with cerebral vasodilatation and high blood pressure, give rise to extensive protein leakage in the brain of NR. Consistent with the hypothesis presented above, less protein leakage occurred in brains of SHR than in brains of NR after amphetamine and bicuculline administration.