AJP - Regulatory, Integrative and Comparative Physiology, Vol 246, Issue 3 277-R288, Copyright © 1984 by American Physiological Society
Blood-brain interfaces in vertebrates: a comparative approach
H. F. Cserr and M. Bundgaard
The neuronal microenvironment in the vertebrate brain is isolated from
plasma by a series of selective membranes, including the blood-brain
barrier, the choroid plexus, and the meningeal barrier. This review deals
with the structure and function of these selective membranes in the
different vertebrate classes. Present knowledge indicates that all
vertebrates have brain barrier membranes and, further, that functional
characteristics of these membranes are basically similar in all the
vertebrate classes. The blood-brain barrier (or capillary-glial complex)
and the meningeal barrier have many of the properties of a tight
epithelium, including the presence of tight junctions and specific
transport mechanisms. The choroidal epithelium is a typical secretory
epithelium. The functional significance of the specialized membranes
located at the blood-brain interface is considered, and we suggest that the
phylogenetic development of a blood-brain barrier provided neurons of the
vertebrate brain with a unique extracellular milieu optimal both for
synaptic communication and for nonsynaptic communication via the entire
extracellular space.
