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Type: Artigo de periódico
Title: Acute Blood-brain Barrier Permeabilization In Rats After Systemic Phoneutria Nigriventer Venom.
Author: Rapôso, Catarina
Zago, Gabriela Mariotoni
da Silva, Gustavo Henrique
da Cruz Höfling, Maria Alice
Abstract: A highly controlled transport of substances at the interface between blood and brain characterizes the blood-brain barrier (BBB), fundamental for maintenance of the homeostasis of the cerebral milieu. In this study, we investigated the time course (15 min, 1, 2, and 5 h) of BBB opening induced by intravenous (i.v.) injection of Phoneutria nigriventer spider venom (PNV) using quantitative and morphological approaches on cerebellum and hippocampus vessels for assessment of BBB permeability. The results showed vasogenic edema and tracer extravasation faster and severalfold higher in hippocampus than in cerebellum. Reactive astrocytes with swollen perivascular end-feet processes were found only in cerebellum. An immediate and total degradation of laminin in capillaries occurred resulting in the disappearance of the basement membrane. In medium-sized vessels, this effect was less prominent. The changes were transient, with cerebellum in general presenting a faster recovery. However, at 5 h laminin was overexpressed, principally in hippocampus. The rapid and abrupt shift of laminin expression in capillaries (at 15 min) coincided with the immediate and severe signs of intoxication shown by the animals, but not with the peak of leakage of vessels and vasogenic edema, which occurred later (1-2 h). The findings suggest a complex regulatory mechanism, since the extension of BBB impairment caused by PNV depends on the region of the SNC, and on the vessels types. It is suggested that the components of the BBB (gliovascular unit) have a critical role in these differences. P. nigriventer venom can be a useful tool to explore the mechanisms of BBB.
Subject: Animals
Basement Membrane
Blood-brain Barrier
Capillary Permeability
Fluorescent Antibody Technique
Microscopy, Electron, Transmission
Rats, Wistar
Time Factors
Rights: fechado
Identifier DOI: 10.1016/j.brainres.2007.02.086
Date Issue: 2007
Appears in Collections:Unicamp - Artigos e Outros Documentos

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