Blood-Brain Barrier Modulations and Low-Level Exposure to Xenobiotics

Hermona Soreq, Daniela Kaufer, Alon Friedman, David Glick

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

3 Scopus citations

Abstract

Separation of the brain from the peripheral blood is crucial for protecting this most delicate and important organ from various insidious agents that circulate in the blood. Conversely, the separation must allow for the nutrition of the brain and the removal from it of waste products. The existence of a physical barrier that separates the brain tissue from the general circulation was first proposed 100 years ago, by Ehrlich, who discovered that injection of a series of dyes into laboratory animals resulted in uncolored brains, as opposed to highly stained visceral organs.1 The blood-brain barrier (BBB) is formed during the late embryonic and early postnatal period. It is an endothelial barrier present in the capillaries throughout the brain, contact-influenced by neighboring astrocytes.2 Electron microscopic studies reveal two major factors that distinguish brain endothelial cells from their peripheral relatives: first, they contain lower amounts of endocytic vesicles, and second, the space between adjacent cells is sealed by tight junctions; both factors restrict intercellular flux. These features enable the formation of a barrier that hinders the entry of most xenobiotics into the brain, and is actively involved in exporting such substances from the brain when they do enter it. Small lipophilic molecules enter the brain fairly freely, but hydrophilic molecules enter via active transport, and specific transporters exist for required nutrients such as glucose, L-DOPA, and certain amino acids.3.

Original languageEnglish
Title of host publicationChemical Warfare Agents
Subtitle of host publicationToxicity at Low Levels
PublisherCRC Press
Pages121-144
Number of pages24
ISBN (Electronic)9781420041576
ISBN (Print)9780849308727
DOIs
StatePublished - 1 Jan 2000

Bibliographical note

Publisher Copyright:
© 2001 by Taylor and Francis Group, LLC.

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