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NEUROPHYSIOLOGY

Blood-Brain Barrier

Figurę 2.3 Biood-Brain Barrier_

The blood-brain barrier (BBB) is the cełlular interface between ihe blood and the central nervous system (CNS: brain and spinał cord). It serves to maintain the interstitial fluid environment to ensure optimal functipnałity oi the neurons. This barrier consists c»f the capillary endothelial cells with an elaborate network ot tight junctions and astrocytic foot processes that abut the endothelium and its basement membranę. The nuwement ot large molecules and other subslam.es (induding many drugs) from the blood to the interstitial space ot the CNS is restrit ted by the BBB. CNS endothelial t eJls also exhibit a Iow k?vel ot pinocytotic activity across the celi, so specific carrier Systems for the transport ol essential substrates of energy and amino acid melabolism are characteristic of thesc cells. The astrocytes help transfer intportant metabolites from the blood to the neurons and also remove excess K' and neurotransmilters from the interstitial fluid.

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