We have examined the effect of antioxidants (vitamin E, and selenium) on the blood-brain barrier permeability during adreneline-induced acute hypertension in the female rats. The rats supplemented with nontoxic doses of sodium selenite in drinking water for three months or vitamin E was given intraperitoneally before adrenaline-induced acute hypertension. Evans-blue was used as a blood-brain barrier tracer. Mean values for Evans-blue dye were found to be 0.28 +/- 0.04 mug/g tissue in control animals and 1.0 +/- 0.2 mug/g tissue after adrenaline-induced acute hypertension (p <.01). Rats pretreated with selenium or vitamin E also showed macroscopic leakage of Evans-blue albumin after adrenaline injection i.e., there was no significant difference in protein extravasation between untreated and treated animals (p >.5). The mean value for Evans-blue dye was found to be 1.0 +/- 0.2 mug/g tissue in acute hypertension group, 0.9 +/- 0.2 mug/g tissue in selenium pretreated animals and 1.0 +/- 0.2 mug/g tissue vitamin E injected animals after acute hypertension. The results show that antioxidants did not influence the blood-brain barrier breakdown during adrenaline-induced acute hypertension.