Blood-brain barrier opening by isotonic saline infusion in normotensive and hypertensive animals

The blood-brain barrier to intravascular Evans blue-albumin was opened in monkeys and rabbits by infusing isotonic saline for 15 s into the common carotid artery, when the external carotid was clamped temporarily and the lingual was catheterized for measuring pressure. Barrier opening correlated better with infusion pressure than with infusion rate, and occurred at carotid artery pressures above 170 mmHg. Systemic hypertension induced by Aramine increased barrier vulnerability by causing a higher net carotid artery pressure to be attained at a given infusion rate.