Demonstration of regional blood-brain barrier permeability in human brain.

The brain of a 78-year-old woman with argyria was examined at autopsy. Silver nitrate deposition was observed in circumventricular organs (CVO) and in the paraventricular and supraoptic nuclei of the hypothalamus. These findings parallel animal experiments of other investigators and are the best demonstration so far of regional absence of the blood-brain barrier in humans. These observations demonstrate similarities between humans and other mammals of CVO anatomy, permeability to blood-borne agents, and perhaps neural connections between CVOs and magnocellular nuclei.