Blood-brain barrier and electromagnetic fields: effects of scopolamine methylbromide on working memory after whole-body exposure to 2.45 GHz microwaves in rats.
We first verified that our 12-arm radial maze test enabled demonstration of memory deficits in rats treated with the muscarinic antagonist scopolamine hydrobromide (0.5mg/kg, i.p.). We then investigated whether a systemically-injected quaternary-ammonium derivate of this antagonist (scopolamine methylbromide; MBR), which poorly crosses the blood-brain barrier (BBB), altered maze performance after a 45-min exposure to 2.45 GHz electromagnetic field (EMF; 2 micros pulse width, 500 pps, whole-body specific energy absorption rate [SAR] of 2.0 W/kg, +/-2dB and brain averaged SAR of 3.0 W/kg, +/-3 dB); if observed, such an alteration would reflect changes in BBB permeability. The drug was injected before or after exposure. Controls were naive rats (no experience of the exposure device) and sham-exposed rats (experience of the exposure device without microwaves). In a final approach, rats were subjected to i.v. injections of Evans blue, a dye binding serum albumin, before or after EMF exposure. Whether scopolamine MBR was injected before or after exposure, the exposed rats did not perform differently from their naive or sham-exposed counterparts. Thus, EMFs most probably failed to disrupt the BBB. This conclusion was further supported by the absence of Evans blue extravasation into the brain parenchyma of our exposed rats.
Cosquer
Brigitte
B
LN2C UMR 7521 Université Louis Pasteur, CNRS, Institut Fédérératif de Recherche 37, GDR CNRS 2905, 12 rue Goethe, F67000 Strasbourg, France.
Vasconcelos
Anne Pereira de
AP
Fröhlich
Jürg
J
Cassel
Jean-Christophe
JC
D000418:Albumins / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000528:radiation effects; D001812:Blood-Brain Barrier / Q000502:physiology / Q000528:radiation effects*; D001930:Brain Injuries / Q000209:etiology / Q000473:pathology; D004334:Drug Administration Schedule; D004574:Electromagnetic Fields; D005070:Evans Blue / Q000378:metabolism; D007839:Functional Laterality; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000528:radiation effects; D008570:Memory, Short-Term / Q000187:drug effects* / Q000528:radiation effects*; D008872:Microwaves; D019832:N-Methylscopolamine / Q000494:pharmacology*; D010276:Parasympatholytics / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014916:Whole-Body Irradiation / Q000379:methods
D000418:Albumins; D010276:Parasympatholytics; D005070:Evans Blue; D019832:N-Methylscopolamine