Journal of Neuroscience, Vol 4, 3069-3079, Copyright © 1984 by Society for Neuroscience
Localization, chromatographic characterization, and development of somatostatin-like immunoreactivity in the guinea pig retina
AW Spira, Y Shimizu and OP Rorstad
We have studied the anatomical localization, chromatographic properties,
and development of somatostatin-like immunoreactivity (SLI) in the guinea
pig retina. The majority of guinea pig retinal SLI in the adult and fetus
eluted similarly to somatostatin-28 by gel filtration and high pressure
liquid chromatography. This represents a higher ratio of
somatostatin-28-like material to total SLI than had been observed in
retinal extracts from most other animal species. Somatostatin-like-
immunoreactive cells and fibers were localized using two antisera in
cryostat-sectioned and flat mounted retinae. Distribution of cells and
fibers differed uniquely from that in other species previously reported.
Reactive perikarya were located only in the far peripheral region: in the
innermost layer of the inner nuclear layer (INL), in the inner plexiform
layer (IPL), and in the ganglion cell layer. Reactive fibers were prominent
in the IPL and nerve fiber layer (NFL) in both the peripheral and central
retina. Less frequently, processes were observed between the NFL and IPL,
between the IPL and INL, and, rarely, in the outer plexiform layer and
outer nuclear layer. Small numbers of reactive fibers were found in the
optic nerve and disc. These observations suggest that processes of
intrinsic (amacrine or associational ganglion cells) and projection neurons
(true ganglion cells or efferent fibers) containing SLI are intermingled in
the guinea pig retina. SLI, quantified by radioimmunoassay, was present in
the developing retina as early as the 6th week of gestation (full term is
10 weeks). Immunohistochemically detected somatostatin-like- immunoreactive
elements were seen first at 2 weeks before birth, coincident with the onset
of the period of most rapid increase in levels of assayed SLI.
Somatostatin-like-immunoreactive peptides reached two-thirds of adult
levels by birth.