Two essential features of the RPE are its polarity and barrier
properties. The RPE is polarized, because it separates the neural
retina from the fenestrated capillaries in the choroid. The apical
membrane of RPE interacts with the photoreceptors; the basal membrane
interacts with the choroid. Like other epithelia, the apical and
basolateral membranes have different protein compositions that enable
each to interact with different environments. For review see:
Wilt SD, Rizzolo LJ: Unique aspects of the blood-brain barrier. In
Tight Junctions, Ed. M. Cereijido and J.M. Anderson, CRC Press, in
press, 2001.
Rizzolo
LJ: Polarity and the Development of the Outer Blood-Retinal
Barrier. Histol. Histopath. 12:1057-1067, 1997.
