J. Navascues et al., MICROGLIA IN THE AVIAN RETINA - IMMUNOCYTOCHEMICAL DEMONSTRATION IN THE ADULT QUAIL, Journal of comparative neurology, 350(2), 1994, pp. 171-186
Immunocytochemical techniques were used in conjunction with the QH1 an
tibody to study the morphological characteristics and distribution of
microglia in the avascular retina of an avian species (the quail). The
majority of microglial cells appeared in the outer and inner plexifor
m layers throughout the entire retina, whereas a few microglial cells
in the nerve fiber layer were seen only in the central zone of the ret
ina, near the optic nerve head. In the outer plexiform layer, microgli
al cells were star-shaped, with processes that ramified profusely in t
he horizontal plane. Fine process tips extended outward radially, insi
nuating themselves among the photoreceptors. A regular mosaic-like arr
angement of microglial cells was evident in the outer plexiform layer,
with no overlapping between adjacent cell territories. Microglial cel
ls in the inner plexiform layer ramified through the entire width of t
his layer, showing radial and horizontal processes. Microglia in the i
nner plexiform layer also tended to be regularly distributed in a mosa
ic-like fashion, although there was slight overlapping between adjacen
t cell territories. Microglia density in this layer was approximately
twice that in the outer plexiform layer. This pattern of microglial di
stribution was similar to that described in vascular retinae of severa
l species of mammals, a finding that suggests that blood vessels are n
ot responsible for the final locations of microglia in the adult retin
a, and that microglial precursors must migrate through long distances
before they reach their precise destination. (C) 1994 Wiley-Liss, Inc.