REVERSIBILITY OF MICROWAVE-INDUCED BLOOD-BRAIN-BARRIER PERMEABILITY

Ultrastructural studies have revealed increased permeation of the blood‐brain barrier by protein in Chinese hamsters after exposure to 2450‐MHz microwaves (CW) at 10 mW cm−2. Reversibility of this microwave‐induced permeability in microvasculature of Wistar rats and Chinese hamsters was assessed. The animals were anesthetized and their heads were irradiated in the near field with 2800‐MHz CW microwaves at 10 mW cm−2 for two hours. Horseradish‐peroxidase protein was injected as a tracer to study its transport across capillaries in all regions of the brain. Gross‐ and electron‐microscopic observations indicated that the relative impermeability of the blood‐brain barrier is re‐established within two hours after irradiation. A significant but incomplete increase of permeability was observed one hour after exposure. Preliminary data indicate that the blood‐ocular barrier was similarly affected. Copyright 1979 by the American Geophysical Union.