The pathophysiology of the blood-brain barrier dysfunction induced by severe hypercapnia and by epileptic brain activity.

The cerebrovascular permeability to protein was studied in hypercapnic rats and in rats with epileptic seizures induced by bicuculline and homocysteine. Despite the differences of the basic pathophysiological mechanisms involved in these models, the blood-brain barrier (BBB) dysfunction was clearly related to the combined effects of high blood pressure and cerebral vasodilatation, thus indicating mechanical factors to be predominantly involved. The BBB changes were most frequent in central and basal regions in contrast to those induced by acute hypertension, which are most common in cortical areas.