Osmotic opening of the blood-brain barrier in the monkey without associated neurological deficits.

Hypertonic urea or lactamide solutions osmotically open the blood-brain barrier in the monkey without producing gross neurological deficits if the blood supply to the brain is not compromised. The brain is perfused via the left lingual artery when the external and common carotid arteries are clamped temporarily. Hypertonic perfusion, which opens the barrier by opening tight junctions between cerebrovascular endothelial cells, can thus be used to study barrier function and brain pharmacology.