Abstract
Amphetamine produces 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 .cntdot. kg-1, diminished the amphetamine-induced extravasation of Evans blue albumin and 125IHSA [human serum albumin] in the rats'' brain. Possible explanations of the effect of dexamethasone on cerebrovascular permeability are discussed.