Cerebral blood flow in cats after an acute hypertensive insult with damage to the blood-brain barrier.

Cerebral blood flow was measured with the 133Xenon clearance method in anesthetized cats under controlled ventilation. An acute pressure increase in the carotid system increases the cerebrovascular permeability to Evans blue, indicating damage to the blood-brain barrier. In these conditions the reactivity or cerebral blood vessels toward changes in the acid-base balance is altered: the CO2 reactivity is less pronounced, while the effect of increasing the plasma (HCO-3) is more pronounced than in normal cats. Autoregulatory capacity toward moderate alterations in arterial blood pressure or in intracranial pressure is well maintained in these conditions.