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Cerebrovascular permeability to 86 Rb in the rat after exposure to pulsed microwaves
Author(s) -
Goldman Harold,
Lin James C.,
Murphy Sharon,
Lin Mei F.
Publication year - 1984
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/bem.2250050305
Subject(s) - permeability (electromagnetism) , microwave , nuclear magnetic resonance , radiochemistry , chemistry , physics , biophysics , biology , membrane , biochemistry , quantum mechanics
Microwaves (pulsed, 2,450 MHz) at an average power density of 3 W/cm 2 were applied directly to the head for 5, 10, or 20 min, producing a peak specific absorption rate of 240 W/kg in the brain, which, after a 10‐min exposure, resulted in brain temperatures in excess of 43°C. A bolus of 86 Rb in isotonic saline was injected intravenously and an arterial sample was collected for 20 s to determine cardiac output. Compared with unexposed controls, uptake of 86 Rb increased most in those regions directly in the path of the irradiation, namely, the occipital and parietal cortex, as well as the dorsal hippocampus, midbrain, and basal ganglia. In a separate group of animals, regional brain‐vascular spaces were found to increase with brain temperature. These results support previous observations indicating that reliably demonstrable increases of blood‐brain barrier permeability are associated with intense, microwave‐induced hyperthermia, and that the observed changes are not due to field‐specific interaction.