Selective Vulnerability of the Blood-Brain Barrier in Chemically Induced Lesions^*

Abstract

1. Vulnerability of the blood-brain barrier to unilateral intracarotid perfusion with chemical injurious agents was studied with the application of various fluorescent and radioactive tracers. 2. Evans blue when bound to albumin fluoresces brightly red in formalin-fixed frozen sections as viewed under ultraviolet light provides a useful and convenient tool for microscopic localization of this tracer. 3. Using fluorescent labeled albumin as a single indicator, several patterns of its abnormal penetration through the damaged cerebral vessels have been elucidated and discussed. 4. Tracing the BBB damage by concurrent intrasystemic administration of albumin and γ-globulin labeled with contrasting fluorescent color markers revealed dissociation features in their extravascular penetration. The albumin indicator spreads, as a rule, more extensively. 5. Differences in extent of penetration were also observed when fluorescent albumin or sodium fluorescein was concurrently used with radioactive inulin or sucrose. 6. A pronounced inhibition of C14methyl-O-glucose brain uptake was observed on the side of a slight mercurial blood-brain barrier damage, which otherwise failed to produce any abnormal penetration of sodium fluorescein. 7. The features of selective vulnerability of the blood-brain barrier are discussed with regard to possible mechanisms involved.