Effect of radiologic contrast media and local anaesthetics on the blood-brain barrier and on the leptomeninges.

The leptomeninges of cats were exposed to lidocaine, metrizamide and methiodal sodium and compared with control brains exposed to Ringer's solution. As a sign of blood-brain barrier damage, an increased extravasation of albumin into the cerebral cortex was recorded after exposure to methiodal sodium; lidocaine or metrizamide did not produce such damage. Scanning electron microscopy revealed minor cellular reactions in the mesothelial cells of the leptomeninges after application of metrizamide, lidocaine and Ringer's solution. Methiodal sodium produced an extensive cellular damage of the leptomeningeal cells. The importance of testing the leptomeningeal reactions and the reactions of the blood-brain barrier to all liquid media used on the brain surface is emphasized.