血脑屏障相关知识.ppt

Key functions of the BBB are: Protecting the brain from foreign substances (such as viruses and bacteria) in the blood that could injure the brain Shielding the brain from hormones and neurotransmitters in the rest of the body Maintaining a constant environment (homeostasis) for the brain (A) Diagram of a brain capillary in cross section and reconstructed views, showing endothelial tight junctions and the investment of the capillary by astrocytic end feet. (B) Electron micrograph of boxed area in (A), showing the appearance of tight junctions between neighboring endothelial cells (arrows). (A after Goldstein, Goldstein and Betz, 1986; B from Peters et al., 1991.) Blood-brain barrier permeability in the mouse brain Blood-brain barrier permeability in the rat brain blood-brain barrier (BBB)  Hua fu Q:279486524 Key functions of the BBB Discovery of the blood-brain barrier Anatomy of the blood-brain barrier Circumventricular organs Factors that can lower the blood-brain barrier Blood-brain border and Glucose Blood-brain barrier permeability in the mouse brain Outline Key functions of the BBB  A mechanism that controls the passage of substances from the blood into the cerobrospinal fluid and thus into the brain and spinal cord. The blood-brain barrier (BBB) lets essential metabolites, such as oxygen and glucose, pass from the blood to the brain and central nervous system (CNS) but blocks most molecules that are more massive than about 500 daltons. This is a low mass in biomolecular terms and means that everything from hormones and neurotransmitters to viruses and bacteria are refused access to the brain by the BBB. It also means that many drugs, which would otherwise be capable of treating disorders of the CNS, are denied access to the very regions where they would be affective.  Discovery of the blood-brain barrier The special properties of the blood-brain barrier were first observed in the late 19th century by the German bac