Intracerebral 6-hydroxydopamine produces extensive damage to the blood-brain barrier in rats.

Extensive extravasation of intravenously administered horseradish peroxidase (HRP) was observed in rat brains infused intranigrally with 8 microgram/4 microliter or 4 microgram/2 microliter 6-hydroxydopamine (6-OHDA), suggesting that the cytotoxin produced widespread alterations in the integrity of the blood-brain barrier. Such damage was dose-dependent and occurred in the mesencephalon around the cannula tip, along the cannula tract, and in the cerebral cortex. The extent of HRP extravasation diminished as a function of increasing time after 6-OHDA administration. These findings indicate that alterations in blood-brain barrier permeability may contribute to the constellation of dysfunctions and possible recovery of function following intranigral infusions of the cytotoxin.