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Increased Susceptibility to Osmotic Disruption of the Blood-Brain Barrier in Chronic Hypertension
Journal article   Open access   Peer reviewed

Increased Susceptibility to Osmotic Disruption of the Blood-Brain Barrier in Chronic Hypertension

KINYA TAMAKI, SEIZO SADOSHIMA and DONALD HEISTAD
Hypertension (Dallas, Tex. 1979), Vol.6(5 Part 1), pp.633-638
09/1984
DOI: 10.1161/01.HYP.6.5.633
PMID: 6500670
url
https://doi.org/10.1161/01.HYP.6.5.633View
Published (Version of record) Open Access

Abstract

We examined the effects of chronic hypertension and acute reduction of arterial pressure on the susceptibility of the blood-brain barrier (BBB) to disruption. The BBB was disrupted with an intracarotid injection of 1.6 M arabinose in spontaneously hypertensive rats (SHR), stroke-prone SHR (SHRSP), and normotensive Wistar-Kyoto (WKY) rats. Permeability of the BBB was determined from the ratio of I-albumin in brain to I-albumin in blood. When the BBB was intact, permeability was less than 0.4%. After hypertonic arabinose, permeability of the BBB was greater (mean ± SE) in SHRSP (17.6% ± 1.6%) and in SHR (21.1% ± 3.1%) than in WKY (10.3% ± 2.4%) (p < 0.05). When arterial pressure of SHRSP was reduced acutely with nitroprusside before arabinose, the BBB permeability to albumin was not reduced (21.5% ± 1.5%). In other rats, we examined survival after osmotic disruption. In SHRSP, 14 of 15 rats died within 1 day after osmotic disruption with marked cerebral edema. In WKY, four of 15 rats died (p < 0.05 vs SHRSP). When arterial pressure of SHRSP was reduced before arabinose, mortality was reduced to six of 15 (p < 0.05 vs untreated SHRSP). We conclude that the BBB in SHRSP has enhanced vulnerability that is detrimental to survival. Reduction of arterial pressure improves survival in SHRSP without affecting BBB permeability to albumin. The findings suggest that 1) there is an inherent defect in the BBB to albumin in SRSP; 2) the increased susceptibility of the BBB is not simply a function of elevated arterial pressure at the time of disruption of the BBB; and 3) the higher mortality in SHRSP after disruption of the BBB is pressure-dependent and readily prevented by reduction of arterial pressure.

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