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 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 109 +/- 5 (mean +/- S.E.) to 185 +/- 8 mmHg, clearance of albumin increased from 0.16 +/- 0.04 to 1.51 +/- 0.34 ml/s x 10(-6). In diabetic rats, when systemic arterial pressure was increased from 117 +/- 3 to 184 +/- 3 mmHg, clearance of albumin increased from 0.22 +/- 0.10 to 1.30 +/- 0.32 ml/s x 10(-6). These findings suggest that the susceptibility of the blood-brain barrier to disruption during acute hypertension is not altered during diabetes mellitus.