EFFECT OF DIABETES-MELLITUS ON DISRUPTION OF THE BLOOD-BRAIN-BARRIER DURING ACUTE HYPERTENSION

The goal of this study was to determine whether the susceptibility of the blood-brain barrier to disruption during acute hypertension is altered during diabetes mellitus. Intravital fluorescent microscopy and fluorescein-labelled albumin were used to evaluate disruption of the blood-brain barrier under control conditions and during acute arterial hypertension in non-diabetic rat and diabetic rats. Permeability of the blood-brain barrier was quantitated by calculating clearance of fluorescent-labelled albumin and by counting the number of microvascular leaky sites under control conditions and during acute hypertension. In non-diabetic rats, when systemic arterial pressure was increased from 105 ± 5 (mean ± S.E.) to 185 ± 8 mmHg, clearance of albumin increased from 0.16 ± 0.04 to 1 ± 0.34 ml/s × 10-6. In diabetic rats, when systemic arterial pressure was increased from 117 ± 3 to 184 ± 3 mmHg, clearance of albumin increased 0.22 ± 0.10 to 1.30 ± 0.32 ml/s × 10-6. These findings suggest that the susceptibility of the blood-brain barrier to disruption during acute hypertension is not altered during diabetes mellitus. © 1990.