Blood-brain barrier dysfunction to peroxidase after air embolism, aggravated by acute ethanol intoxication.

Ethanol-intoxicated and non-intoxicated rats were injected with horseradish peroxidase and Evan's blue-labelled albumin and given a small air embolus in the right common carotid artery after ligation of the external carotid branch. In both ethanol-intoxicated and non-intoxicated rats, some endothelial cells, mainly in arteries and arterioles, showed a diffuse distribution of peroxidase in the cytoplasm. In some arterioles with a diffuse endothelial distribution of peroxidase there was a detachment of endothelial cells from the vessel wall, with an exposure of the adluminal basement membrane to blood elements. This endothelial detachment was mainly observed in ethanol-intoxicated rats. The vascular basement membranes underlying detached endothelial cells contained peroxidase, both in ethanol-intoxicated and in non-intoxicated rats. There was a considerable leakage of peroxidase via endothelial pinocytotic vesicles into the vascular basement membranes, mainly in arterioles, but also in capillaries and venules of the embolised hemisphere. This transendothelial pinocytotic transport of peroxidase was more prominent in ethanol-intoxicated than in non-intoxicated rats.