Journal of Neuroscience, Vol 6, 1272-1283, Copyright © 1986 by Society for Neuroscience
Immunofluorescent localization of two different Na,K-ATPases in the rat retina and in identified dissociated retinal cells
KM McGrail and KJ Sweadner
Two isozymes of the Na,K-ATPase are made in the brain and retina. Antisera
have been produced that contain antibodies specific for each of the
catalytic subunits of the two isozymes, alpha and alpha(+) (Sweadner &
Gilkeson, 1985a). To determine which classes of cells express which form of
the Na,K-ATPase, and whether cells can express both forms, the antisera
were used to stain sections of the rat retina and dissociated retinal cells
by indirect immunofluorescence. In sections of the retina, bright stain
specific for both isozymes was seen in the inner segments of the
photoreceptor cells, the outer and inner plexiform layers, and in the
ganglion cell axons. Cell bodies were outlined in the inner nuclear layer.
Stain specific for the alpha isozyme was seen in adhering pigment
epithelium and at the position of the apical processes of the Muller glial
cells. In sections of the optic nerve, the nerve itself stained for both
isozymes, although the stain for the alpha(+) isozyme was stronger. The
sheath, in contrast, stained selectively for the alpha isozyme. Cells were
dissociated from the retina, and they were identified by their morphology
and by cell class-specific monoclonal antibodies. Muller glial cells were
found to stain brightly for only the alpha isozyme, while horizontal and
ganglion cells stained brightly for both isozymes. Bipolar cells stained
faintly for only the alpha(+) isozyme, while amacrine cells stained faintly
for both isozymes. The evidence indicates that different kinds of neurons
can express one or both isozymes of the Na,K- ATPase, and at quantitatively
different levels.