Effect of dexamethasone on protein extravasation in the brain in acute hypertension induced by amphetamine.

Amphetamine productes protein leakage in the brain when given to rats under nitrous oxide anesthesia. The blood-brain barrier dysfunction is caused by the combined effect of blood pressure increase and vasodilatation. In the present experiments pretreatment with dexamethasone, 2 mg.kg-1, diminished the amphetamine-induced extravasation of Evans blue albumin and 125IHSA in the rats' brain. Possible explanations to the effect of dexamethasone on cerebrovascular permeability are discussed.