Abstract
The leptomeninges, superficial subpial brain tissue and some blood vessels became radioactive following a subarachnoid injection of iodinated bovine albumin. Contact autographs and histological sections were made of brains from 20 adult rabbits, 6 dogs and 3 cats in this study. The radioactivity noted was attributed to 2 routes, absorption onto the leptomeninges or penetration along the meningeal surface of the brain and along some penetrating blood vessels. Twenty minutes after injection only the leptomeninges were radioactive, after 3 hours the most intense and extensive reactions appeared and after 24 no radioactivity was apparent in the autographs. No species differences were observed and variations in the amount of fluid injected had no appreciable effect on the intensity of distribution of radioactivity. These experiments indicate that radioactive iodinated albumin molecules can penetrate nervous tissue from the cerebrospinal fluid thus supporting the idea that pathogenic agents could travel from the cerebrospinal fluid along the perivascular spaces into the nervous tissue.