[Abstract Title]. - Society for Neuroscience

after direct probe implantation, i.e without guide cannula. At this time point, acute tissue damage
caused by the stereotaxic implantation has declined, while potential long term tissue alteration,
such as gliosis around the probe, has not yet evolved. A suitable test substance to measure barrier
breakdown should have a very low permeability at the healthy BBB and not be a substrate of any
influx or efflux transport system. Hence, to determine the effect of probe implantation on BBB
integrity, we measured the permeability of a low molecular hydrophilic solute, [ 14 C]sucrose. For
this, 24 hr after probe implantation, [ 14 C]sucrose (40µCi/animal) was injected intravenously
followed by collection of plasma samples and brain extracellular fluid (ECF) dialysate samples
for different time periods. The permeability surface area product (PS) of [ 14 C]sucrose at the BBB
was calculated based on dialysate values, and compared to values determined by the „classical‟
method of whole tissue sampling. Within the time period covered in our study (30 min), we
found that the PS product of [ 14 C]sucrose determined by microdialysis (0.37 ± 0.1 µl/min/gm)
was not significantly different from that determined by the classical method (0.34 ± 0.02
µl/min/gm), suggesting that microdialysis probe implantation does not result in significant BBB
leakage to a poorly permeable drug-like substance.
Disclosures: R.K. Sumbria , None; U. Bickel, None.
Poster
287. Blood Brain Barrier and CSF
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 287.7/RR1
Topic: E.09.c. Blood brain barrier
Support: CONACyT SEP-2004-C01-48002
Title: Ultrastructural vascular permeability changes in the brain circumventricular organs of
adult rats, in response to electromagnetic fields (120Hz harmonic waves and 0.66mT rms)
Authors: *Y. K. GUTIERREZ-MERCADO 1 , L. CAÑEDO-DORANTES 3 , J. BAÑUELOS-
PINEDA 2 , G. SERRANO 3 , A. FERIA-VELASCO 1 ;
1 Cell Biol. and Mol., 2 Vet., Univ. Guadalajara, Zapopan Jalisco, Mexico; 3 Medicin, Autonomous
Univ. of Morelos, Cuernavaca Morelos, Mexico
Abstract: A limited number of studies dealing with the effects of electromagnetic fields (EMF)
have been reported, mainly referring to microcirculation and microvasculature related to
pressure. There are few reports on the effects of EMF on vascular permeability of brain blood
vessels and no studies have been published as the evaluation of the effects of EMF on vascular
permeability to non-liposoluble substances of some CVO of the adult rat, at light microscopy and