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The Journal of Neuroscience, August 15, 1998, 18(16):6549-6557
Neurofilament Proteins in Y-Cells of the Cat Lateral Geniculate
Nucleus: Normal Expression and Alteration with Visual Deprivation
Martha E.
Bickford1,
William
Guido2, and
Dwayne
W.
Godwin3
1 Department of Anatomical Sciences and Neurobiology,
University of Louisville, School of Medicine, Louisville, Kentucky
40292, 2 Department of Cell Biology and Anatomy, Louisiana
State University Medical Center, New Orleans, Louisiana 70112, and
3 Department of Neurobiology and Anatomy, Wake Forest
University School of Medicine, Winston-Salem, North Carolina 27157-1010
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ABSTRACT |
We examined neurofilament staining in the normal and visually
deprived lateral geniculate nucleus (LGN), using the SMI-32 antibody.
This antibody preferentially stains LGN cells that display the
morphological characteristics of Y-cells. The soma sizes of SMI-32-stained cells were consistent with those of the overall population of Y-cells, and the Golgi-like staining of their dendrites revealed a radial distribution that often crossed laminar boundaries. Labeled cells were distributed within the A laminae (primarily near
laminar borders), the magnocellular portion of the C laminae, and the
medial intralaminar nucleus, but they were absent in the parvocellular
C laminae. Electron microscopic examination of SMI-32-stained tissue
revealed that staining was confined to somata, dendrites, and large
myelinated axons. Retinal synapses on SMI-32-labeled dendrites were
primarily simple axodendritic contacts; few triadic arrangements were
observed. In the LGN of cats reared with monocular lid suture, SMI-32
staining was decreased significantly in the A laminae that
received input from the deprived eye. Dephosphorylation of the tissue
did not alter the cellular SMI-32 staining patterns. Analysis of
staining patterns in the C laminae and monocular zone of the A laminae
suggests that changes in the cytoskeleton after lid suture reflect cell
class and not binocular competition. Taken together, the results from
normal and lid-sutured animals suggest that the cat LGN offers a unique
model system in which the cytoskeleton of one class of cells can be
manipulated by altering neuronal activity.
Key words:
SMI-32; electron microscopy; monocular deprivation; immunocytochemistry; thalamus; cytoskeleton
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INTRODUCTION |
The SMI-32 antibody stains the
nonphosphorylated form of the high-molecular-weight neurofilament
protein. It has been used extensively to document cytoskeletal changes
in a number of neurological disorders (Sternberger et al.,
1985 ; Troncoso et al., 1986; Hof and Morrison, 1990; Hof et al., 1990;
Vickers et al., 1992; Duong and Gallagher, 1994; Gai et al., 1994;
Smith et al., 1995; Su et al., 1996). Decreases in neurofilaments, or
abnormal phosphorylation of neurofilaments, appear to be frequent
consequences of neuronal disease or damage, but the sequence of events
leading to these changes is unknown. An understanding of the normal
functions of the cytoskeleton, and the potential transformations that
occur during neuronal disease, requires an animal model. The lateral geniculate nucleus (LGN) of the cat is an excellent candidate for such
a model. Its anatomy and physiology are well characterized, both in the
normal condition as well as after experimental manipulations that
produce subtle, yet reproducible, changes in neuronal morphology.
The pathway from retina through the LGN is composed of at least two (X
and Y), perhaps three (W), morphologically and physiologically distinct
neuronal streams. Each is designed to analyze different aspects of the
visual scene (Sherman, 1985). These pathways develop at different rates
and also respond differently to abnormal visual input (Friedlander et
al., 1982; Sherman and Spear, 1982; Sur et al., 1982, 1984; Garraghty
et al., 1986, 1988). For example, Y-cells seem particularly susceptible
to monocular lid suture (MS). After early periods of MS, Y-cells in the
LGN develop abnormal receptive field properties and show a reduced soma
size and anomalous dendritic morphology. The abnormally thin and
tangled dendrites of Y-cells in deprived laminae suggest an alteration
in cytoskeletal support. Thus, MS may be a useful model to study how
modifications in neuronal activity can alter the organization of
neurofilaments.
The aim of the present study was to examine the staining pattern of the
SMI-32 antibody in the LGN of normal cats and cats raised with MS. This
antibody recently has been shown to stain preferentially the
magnocellular layers of the monkey LGN (Gutierrez et al., 1995;
Chaudhuri et al., 1996). However, SMI-32 staining has yet to be
explored in the cat LGN, where the Y-cell pathway is well characterized
and can be manipulated readily by altering visual input.
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MATERIALS AND METHODS |
A total of five cats were used for these experiments. Two were
normal adult cats. Three other adult cats were reared with monocular
lid suture that was performed before eye opening and was maintained
until death (for details on lid suture, see Friedlander et al.,
1982). The cats were given an overdose of sodium pentobarbital and
perfused through the heart with saline, followed by a fixative solution
of 4% paraformaldehyde (one normal and two MS) or 4% paraformaldehyde
and 0.5% glutaraldehyde (one normal) or 2% paraformaldehyde and 0.1%
glutaraldehyde (one MS) in 0.1 M sodium phosphate buffer (PB), pH 7.4. Previous studies that used the SMI-32 antibody excluded the use of glutaraldehyde fixation (Campbell and Morrison, 1989). However, we found that, although the low percentage of glutaraldehyde slightly decreased the staining intensity, the overall staining pattern
was similar with each fixation protocol.
After fixation, the brains were removed and cut in the coronal or
sagittal plane into 50-µm-thick sections with a vibratome. Series of
sections from all five cats were stained with the SMI-32 antibody.
Series of sections from two cats (one normal and one MS) were mounted
on slides and stained for Nissl substance. Additional sections from two
cats (one normal and one MS) were incubated in alkaline phosphatase
(400 µg/ml; Sigma type VII-L, Sigma, St. Louis, MO) in 0.1 M Tris buffer, pH 8, for 2 hr at 37°C, rinsed in Tris
buffer, and stained with the SMI-32 antibody as described below.
For immunocytochemistry, sections through the LGN were incubated in
10% normal goat serum (NGS) in PBS (0.01 M; 0.9%
NaCl) for 30 min. Then the sections were transferred to a solution of the SMI-32 antibody (monoclonal, made in mouse, Sternberger Monoclonal, Jarrettsville, MD) diluted 1:5000, 1:10,000, or 1:20,000 in 1% NGS in
PBS with 0.5% Triton X-100 and incubated overnight with agitation at
4°C. The next day the sections were rinsed three times (10 min each)
in PB and incubated for 1 hr in a 1:100 dilution of biotinylated goat
anti-mouse antibody (Vector Laboratories, Burlingame, CA) in 1% NGS in
PBS. Then the sections were rinsed three times (10 min each) in PB and
incubated for 1 hr in a 1:100 dilution of a complex of avidin and
biotinylated horseradish peroxidase (ABC; Vector Laboratories) in 1%
NGS in PBS. The sections were rinsed three times (10 min each) and
reacted with nickel-enhanced diaminobenzidine solution (Adams, 1981)
for 5 min. The sections were rinsed and mounted on slides or prepared
for electron microscopy as described below.
For electron microscopy the sections were post-fixed in osmium (2% in
PB) for 1 hr, rinsed, dehydrated in an ethanol series, and embedded in
Durcupan resin (Ted Pella, Redding, CA). Sections were cut from the
resin blocks on an ultramicrotome, collected on Formvar-coated slot
grids, stained with uranyl acetate (10% in methanol) for 30 min, and
examined with a transmission electron microscope. SMI-32-labeled
dendrites postsynaptic to retinal terminals were photographed.
Drawings of soma sizes from Nissl- and SMI-32-stained tissue were made
with a camera lucida. The areas of these drawings subsequently were
measured by a digitizing tablet and SigmaScan computer software (Jandel
Scientific, Corte Madera, CA). For statistical analysis of soma sizes,
a two-tailed nonparametric Mann-Whitney U test was used to
evaluate the differences between population means. To determine the
underlying distributions of cell soma size, we pooled the soma area
data from the A laminae. We assumed for this analysis that the
underlying distributions of neuronal soma sizes were distributed
normally. We fit the histograms derived from these pooled data with
gaussian functions, using the PStat program (Axon Instruments, Foster
City, CA). Using a Simplex fitting algorithm, we achieved the
best fit (least mean error per data point) for the Nissl data with two
gaussian terms and with one gaussian term for the SMI-32 data. We
evaluated with a comparison of Z scores whether significant
differences existed between the gaussian distributions derived from
these fits.
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RESULTS |
Nature of SMI-32 label in the normal LGN
A number of observations suggest that SMI-32 staining in the
normal LGN is restricted to the Y-cell population. First, the distribution of staining is similar to that of Y-cells (Sherman, 1985).
As shown in Figure 1, cells are
distributed in laminae A, A1, the magnocellular portion of C, and the
medial intralaminar nucleus (MIN), but the cells are lacking in
parvocellular C laminae (C1-C3). Within the A laminae, the majority of
the SMI-32-stained cells is near the laminar boundaries.
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Figure 1.
SMI-32-stained cells in the normal LGN match the
distribution of Y-cells. Stained cells are located in laminae
A and A1, the magnocellular portion of
the C laminae (C), and medial intralaminar
nucleus (MIN), as shown in coronal
(A) and sagittal (B)
sections through the LGN. Higher magnification
(C) shows that stained cells are located near
laminar borders, and their radially distributed dendritic arbors cross
laminar borders. Scale bars: in A (also applies to
B), 1 mm; in C, 100 µm.
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In addition, the morphology of SMI-32-stained cells is similar to that
of Y-cells. As shown in Figures 1C and
2, well stained cells exhibit class I
morphology (Guillery, 1966; Friedlander et al., 1981; Wilson et al.,
1984; Raczkowski and Sherman, 1985); they have large somata, with
numerous radiating dendrites. SMI-32-stained dendrites frequently cross
the interlaminar zone between the A laminae as well as the boundary
between the A1 and C laminae (Figs. 1C, 2C).
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Figure 2.
SMI-32-stained cells in the normal LGN display
class I morphology. A, Cell in lamina A. B, Cell in lamina A1. C, Cell in lamina
A1 extending dendrites into the interlaminar zone (border indicated by
the dashed line). D, Cells in the medial
intralaminar nucleus. Scale bar in A (also applies to
B-D), 50 µm.
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Like Y-cells, SMI-32-stained cells are the largest in the LGN, as
demonstrated by a comparison of the soma areas of cells stained for
Nissl substance to those stained with the SMI-32 antibody (Fig.
3). The size of SMI-32-stained cells is
significantly different from the overall population of LGN cells (Fig.
3A; n = 400 Nissl and 400 SMI-32;
p < 0.0001) as well as cells in either laminae A or A1
(Fig. 3B,C; n = 100 Nissl and 100 SMI-32;
p < 0.0001 for lamina A and A1). In the magnocellular
C lamina there is a slight, but significant, difference in the size
distribution of SMI-32-stained cells and Nissl-stained cells (Fig.
3D; n = 100 Nissl and 100 SMI-32;
p < 0.003). In the interlaminar zone between lamina A and A1 there was no significant difference between the sizes of SMI-32-stained and Nissl-stained cells (Fig. 3E;
n = 100 Nissl and 100 SMI-32).
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Figure 3.
SMI-32-stained cells are the largest in the
LGN. Histograms compare the distribution of soma areas of samples of
Nissl- and SMI-32-stained cells in adjacent sections. A,
Pooled data (400 Nissl- and 400 SMI-32-stained cells) from all laminae.
B, The 100 Nissl- and 100 SMI-32-stained cells from
lamina A. C, The 100 Nissl- and 100 SMI-32-stained cells
from lamina A1. D, The 100 Nissl- and 100 SMI-32-stained
cells from lamina C. E, The 100 Nissl- and 100 SMI-32-stained cells from the interlaminar zone between lamina A and
A1.
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In addition to these comparisons, we also examined whether there were
significant differences between the population of larger (presumably Y)
cells and the SMI-32-stained neurons. The LGN A laminae contain three
major types of cells: X- and Y-cells and interneurons. The soma size
distributions of these populations overlap, which prompted our effort
to fit gaussians to the data set in an attempt to derive the underlying
distribution functions of these cells. However, we note that the best
fits of the pooled A laminae Nissl data were achieved with two gaussian
terms. This likely reflects that two of these types could not be
discriminated with the sample size we used. Of the three, previous
studies have shown the most overlap between X-cells and interneurons
(Friedlander et al., 1981). Thus, the distribution of large
Nissl-stained cells likely represents the distribution of Y-cells. As
is apparent from the graphical comparison of gaussian distributions in
Figure 4, the distribution of
SMI-32-stained neurons was significantly different from that of the
small Nissl-stained cells (p < 0.001), but not
significantly different from the distribution of large Nissl-stained
cells. Thus, the most reasonable interpretation of these data is that
the antibody is labeling Y-cells.
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Figure 4.
The soma areas of SMI-32-labeled cells are
consistent with the population of Y-like cells. Histograms show the
pooled data from the A laminae of LGN (see Fig. 3B,C).
Gaussian functions were fit to the data by a Simplex least-squares
algorithm. The two gaussians derived from the Nissl data significantly
differ from each other, but the gaussians fitting the SMI-32 data and
the larger population of Nissl-labeled cells were not significantly
different.
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Electron microscopic examination of SMI-32-stained tissue (lamina A)
confirmed that label is found in somata and dendrites. Within somata
the label displayed a patchy distribution that was not clearly
associated with any particular organelle (Fig.
5A). The label was seen to
coalesce as dendrites emerged from somata, and most dendritic staining
was distributed evenly throughout the cytoplasm. In some cases,
reaction product was denser toward synaptic contact zones or puncta
adherentia (Fig. 5B-E).
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Figure 5.
Ultrastructure of SMI-32 staining in the normal
LGN. A, SMI-32 staining in cell somata is patchy and
becomes more intense in dendrites. B-D, Simple
axodendritic contacts (arrows) are made between retinal
terminals and SMI-32-stained dendrites, although retinal terminals also
may contact unlabeled dendritic terminals (asterisk in
B). E, SMI-32 staining also is seen at
puncta adherentia (arrowheads). Scale bars: in
A, 5 µm; in B (also applies to
C-E), 1 µm.
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A sample of 52 synaptic contacts made by retinal terminals onto
SMI-32-stained dendrites was examined. Retinal terminals can be
identified on the basis of their morphology as large
terminals with round vesicles and pale
mitochondria (RLP profiles). Previous studies indicate that
Y-cells receive retinal contacts on proximal dendritic shafts; the
synaptic arrangements of RLP profiles on Y-cells are generally less
complex than those made by RLP profiles that innervate the dendritic
appendages of X-cells (Wilson et al., 1984; Hamos et al., 1986, 1987;
Bickford et al., 1992). Consistent with the hypothesis that SMI-32
stains Y-cells, a majority of contacts between RLP profiles and
SMI-32-stained dendrites were simple axodendritic contacts on dendritic
shafts. Occasionally (13 of 52 or 25%), retinal terminals presynaptic
to SMI-32-labeled dendrites also contacted dendritic terminals (F2
profiles; Fig. 5B). However, only one triadic arrangement
(frequently seen in the X-cell pathway; Wilson et al., 1984; Hamos et
al., 1987) was encountered in the sample that was examined.
Axonal labeling with SMI-32 was also consistent with staining in
Y-cells. Intensely stained axonal profiles were of large caliber and
heavily myelinated (Friedlander et al., 1981; Humphrey et al.,
1985a,b). These axons did not contain pale mitochondria and thus were
not retinal axons. The distribution and size of these axons suggested
that they were thalamocortical Y-cell axons, most likely originating
from the SMI-32-stained cells. However, if this is the case, the
staining did not extend far from the somata, because axonal labeling
was not seen in the optic radiations.
SMI-32 labeling after early monocular lid suture
Because the SMI-32 antibody appears to stain Y-cells
preferentially, it was of interest to examine staining with this
antibody in cats raised with MS, a manipulation that affects the form
and function of the Y-cell pathway. As illustrated in Figures
6 and 7,
SMI-32 staining is reduced dramatically in geniculate A laminae deprived of normal visual input. The number of well stained cells and
the general neuropil staining are both decreased in the deprived laminae when compared with the nondeprived laminae. Within the nondeprived laminae, cells with class I morphology continue to stain
with the SMI-32 antibody. Within the deprived laminae, occasional cells
that display class I morphology are labeled, but the staining intensity
is decreased when compared with cells stained in the nondeprived
lamina.
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Figure 6.
After MS, SMI-32 staining is reduced in the
deprived A laminae. Shown are caudal (A,
B) and rostral (C, D)
sections through the LGN of a cat with right MS. In the left LGN
(A, C), staining is reduced in lamina A. In the right LGN (B, D), staining is
reduced in lamina A1. Scale bar in A (also applies to
B-D), 1 mm.
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Figure 7.
SMI-32-stained cells in C laminae and the
nondeprived A laminae of MS cats display class I morphology. Shown is a
section through the left (A) and right
(B) LGN of a cat with right MS. Scale bar in
A (also applies to B), 100 µm.
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In contrast to the A laminae, the SMI-32 staining in lamina C is
intense on both sides of the LGN of monocularly deprived cats. As
previously described (Wiesel and Hubel, 1963; Guillery and Stelzner,
1970; Hickey, 1980; Murakami and Wilson, 1983, 1987), the deprived
lamina C is slightly thinner than the nondeprived lamina C (Figs.
6-8). Nonetheless, both deprived and
nondeprived lamina C cells are well stained with the SMI-32 antibody
and display normal class I morphology. However, some differences were
detected when the soma sizes of lamina C cells on either side of the
LGN were compared. In each of the three cases the SMI-32-stained cells in deprived lamina C were slightly smaller (15%) than those in the
nondeprived lamina C. The size differences of samples of 100 SMI-32-stained cells in the deprived and nondeprived C laminae were
significant in each of the three cases (Fig.
9; case 97-11, p < 0.001; case 97-16, p < 0.0001; case 97-17, p < 0.0001).
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Figure 8.
Cells in both the deprived and nondeprived C
laminae stain with the SMI-32 antibody. Shown are the left
(A) and right (B) C laminae
of a cat with right MS. The borders between the A1 and C lamina are
indicated by lines. The arrows point to
cells shown at higher magnification in C and
D. Scale bars: in A (also applies to
B), 100 µm; in C (also applies to
D), 20 µm.
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Figure 9.
SMI-32-stained cells in the deprived lamina C are
smaller than SMI-32-stained cells in the nondeprived lamina C. Histograms illustrate the soma size distributions of C lamina cells
from three MS cats.
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It is also apparent that, unlike other changes associated with MS, the
reduction in SMI-32 staining occurs in both the binocular and monocular
segments of lamina A. As previously reported for Nissl-stained sections
(Guillery and Stelzner, 1970), cells in the deprived binocular segment
are noticeably smaller than those in the monocular segment (Fig.
10A,B). However, in
adjacent sections it is apparent that, although monocular segment cells
have normal soma sizes, they do not retain their normal capacity to
stain with the SMI-32 antibody (Fig. 10C,D). In contrast,
the deprived monocular segment of lamina C is stained with the SMI-32
antibody, indicated by a band of label beneath the monocular segment of lamina A.
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Figure 10.
SMI-32 staining is reduced in both the
binocular and monocular zones of the deprived A lamina. Shown are the
Nissl-stained (A, B) and SMI-32-stained
(C, D) sections through the left LGN of a
cat with right MS. The border between the binocular and monocular zones
is indicated by lines in A and
C. Higher magnifications of the deprived monocular zone
are shown in B and D. Monocular lamina A
and C indicated. Scale bars: in A (also applies to
C), 500 µm; in B (also applies to
D), 100 µm.
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Alkaline phosphate pretreatment
To begin to examine possible mechanisms that could account for the
decrease in SMI-32 staining after monocular deprivation, we pretreated
sections with alkaline phosphatase before immunocytochemical staining.
This treatment has been used previously to reveal abnormal phosphorylation of neurofilaments (Su et al., 1996). As shown in Figure
11A, SMI-32 staining
in normal tissue revealed few axons because axonal neurofilaments
normally are phosphorylated, and the SMI-32 antibody recognizes only
nonphosphorylated neurofilament proteins. As shown in Figure
11B, dephosphorylation of the tissue before SMI-32
staining resulted in a dramatic increase in axonal staining. However,
the alkaline phosphatase pretreatment did not affect the overall
pattern of cellular staining in the monocularly deprived LGN. The
nondeprived laminae served as an internal control for any effects of
the alkaline phosphatase treatment on the intensity of cellular SMI-32
staining. After alkaline phosphatase pretreatment the SMI-32 antibody
stained cells in the nondeprived laminae. However, staining was still
reduced in the deprived A laminae as compared with the nondeprived A
laminae. Thus, it is unlikely that abnormal phosphorylation of
neurofilaments accounts for the loss of SMI-32 staining in LGN cells
deprived of normal visual input.
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Figure 11.
Alkaline phosphatase treatment before SMI-32
staining does not alter the cellular staining pattern in the LGN.
SMI-32 staining is reduced in the right LGN A1 lamina of a cat with
right MS (A). Pretreatment of the tissue with
alkaline phosphatase (B) increases axonal
labeling, but cellular staining remains reduced in the deprived lamina
A1. Scale bar in A (also applies to B), 1 mm.
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DISCUSSION |
The SMI-32 antibody as a marker for Y-cells
This study shows that the SMI-32 antibody preferentially stains
Y-cells in the cat LGN. The distribution, morphology, and synaptic
arrangements of LGN cells stained with this antibody match the
characteristics of Y-cells. This is consistent with previous reports
that the SMI-32 antibody preferentially stains the magnocellular layers
in the monkey LGN (Gutierrez et al., 1995; Chaudhuri et al., 1996). In
other areas of the brain, specific subsets of neurons stain with the
SMI-32 antibody. In general, cells stained by this antibody are large,
with thick dendrites and/or large-diameter axons. For example, the
SMI-32 antibody stains the stout apical dendrites of cortical pyramidal
cells (Campbell and Morrison, 1989; Carmichael and Price, 1994; del Rio
and Defelipe, 1994; Cusick et al., 1995; Hof and Morrison, 1995; Hof et
al., 1995). Within the visual system large cells in other structures
are labeled. For example, the SMI-32 antibody labels a subset of large
neurons in the pulvinar nucleus of the monkey (Gutierrez et al., 1995),
and, in the retina, a relation to the Y-cell pathway has been
demonstrated; in a variety of species SMI-32 or other neurofilament
antibodies have been shown to stain large  -ganglion cells (Drager et
al., 1984; Gabriel and Straznicky, 1992; Straznicky et al., 1992).
Evidence that neurofilament changes are attributable to cell
class competition
Two mechanisms have been proposed to account for the changes seen
in the LGN after MS, namely, cell class and binocular competition. Cell
class competition arises in laminae A and A1, where X and Y
retinogeniculate arbors co-mingle and compete for terminal space on
their geniculate cell counterparts. After MS, Y retinogeniculate arbors
are reduced significantly, whereas the X retinogeniculate arbors
maintain a broad terminal field (Sur et al., 1982; Garraghty et al.,
1986). Thus, the Y-relay cells receive less, or abnormal, retinal input
(Friedlander et al., 1982). Binocular competition arises in portions of
the LGN where input from the two eyes innervate separate laminae. In
this case, competitive mechanisms in the cortex result in reduced
thalamocortical arbors arising from cells in the deprived laminae
(Shatz and Stryker, 1978; Friedlander and Martin, 1991). This leads to
a corresponding reduction in the soma sizes of cells in the binocular
portions of the deprived laminae (Guillery and Stelzner, 1970;
Guillery, 1972). It has been proposed that the abnormal properties of
Y-cells seen in the binocular portions of the A laminae result from the
combined effects of both cell class and binocular competition (Spear et al., 1989).
Our results suggest that the reduction in SMI-32 staining that
accompanies MS is attributable to cell class competition and not to
binocular competition. SMI-32 staining is reduced only in A-laminae,
where X and Y retinogeniculate arbors compete for terminal space. In
laminae C, where cells are subject to binocular competition but not
cell class competition, cells retain their ability to stain with the
SMI-32 antibody. In the monocular zone of lamina A, where cells are
subject to cell class competition but not binocular competition, SMI-32
staining is lost (Sherman and Spear, 1982; Spear et al., 1989).
Indeed, these results also suggest that the consequences of MS on
Y-cell morphology are attributable to different mechanisms. Changes in
the cytoskeleton of Y-cells, which presumably account for the changes
seen in dendritic morphology (Friedlander et al., 1982), appear to be
attributable to cell class competition. In contrast, changes in soma
size that appear to occur independent of the cytoskeletal changes are
attributable mainly to binocular competition (Guillery and Stelzner,
1970; Guillery, 1972; Sherman et al., 1975). Thus, the nature of the
input that Y-cells receive may have a major influence on the
organization of their neurofilaments, whereas the extent of their
axonal arbors influences their soma size.
Modifications of the neuronal cytoskeleton
Our results suggest that abnormal input to Y-cells induces a
restructuring of their cytoskeleton. Other reported changes in neurofilaments, resulting from neurological disorders and after a
variety of experimental conditions, indicate the dynamic nature of the
neuronal cytoskeleton (Sternberger et al., 1985; Troncoso et al., 1986;
Hof and Morrison, 1990; Hof et al., 1990; Vickers et al., 1992; Duong
and Gallagher, 1994; Gai et al., 1994; Smith et al., 1995; Su et al.,
1996). In the visual cortex of cats with monocular lid suture or
monkeys with monocular tetrodotoxin injections, neurofilament staining
becomes patchy (Eckert et al., 1997; Yoshioka, 1997), suggesting that
cortical cells receiving input from the deprived eye also undergo
cytoskeletal changes.
A well documented change in neurofilaments is abnormal phosphorylation.
Generally, in adult tissue, neurofilaments in somata and dendrites are
not phosphorylated, but those in axons are (Matus, 1988). The
phosphorylation of neurofilaments in axons may allow the bundling of
groups of neurofilaments, which confers compactness and stability to
the axonal cytoskeleton. In Alzheimer's disease the neurofilaments in
somata become abnormally phosphorylated, and this abnormal
phosphorylation appears to accompany the formation of neurofibrillary
tangles (Sternberger et al., 1985; Duong and Gallagher, 1994).
Additionally, it is the cortical neurons that normally stain with the
SMI-32 antibody that are particularly susceptible to cytoskeletal
changes during Alzheimer's disease (Hof et al., 1990). One explanation
for the vulnerability of SMI-32-positive neurons to cytoskeletal
changes may be that the large C terminus of the NF-H protein has a high
affinity for several kinases that phosphorylate the protein (Wible et
al., 1989; Xiao and Montiero, 1994).
We ruled out abnormal phosphorylation of neurofilaments as a reason for
the decreased SMI-32 staining of Y-cells in the deprived laminae,
because removal of phosphate in sections pretreated with alkaline
phosphatase did not alter the cellular staining pattern. A similar
result was found in the substantia nigra of brains from patients with
Parkinson's disease (Gai et al., 1994). Compared with the
substantia nigra of control brains, the percentage of SMI-32-stained
cells in the diseased brains was reduced, and this pattern remained in
tissue pretreated with alkaline phosphatase. These authors suggested
that the reduced SMI-32 staining might mark an initial stage of
neuronal degeneration in which neurofilaments are one of the first
proteins to be degraded.
Because LGN cells in deprived laminae do not degenerate, it is unlikely
that the decreased SMI-32 staining shown in this study represents a
process of neuronal degeneration. Thus, it remains to be determined
whether deprived LGN Y-cells lack neurofilaments or whether their
neurofilaments are reorganized such that they are not recognized by the
SMI-32 antibody. In either case, our results demonstrate that changes
in synaptic input can influence the organization of the neuronal
cytoskeleton and suggest that the cat LGN offers a novel model system
to study the normal function and pathological reorganization of
neurofilaments.
| |
FOOTNOTES |
Received Feb. 3, 1998; revised May 6, 1998; accepted June 2, 1998.
This work was supported by National Institute of Neurological Diseases
and Stroke Grant R29NS35377 and National Science Foundation Grant
97628089 to M.B., National Science Foundation Grant 9396270 to W.G.,
and National Eye Institute Grant EY11695 to D.G. We thank Martin Boyce
for his excellent technical assistance.
Correspondence should be addressed to Dr. Martha E. Bickford,
Department of Anatomical Sciences and Neurobiology, 500 South Preston
Street, University of Louisville, School of Medicine, Louisville, KY
40292.
| |
REFERENCES |
-
Adams JC
(1981)
Heavy metal intensification of DAB-based HRP reaction product.
J Histochem Cytochem
29:775[Web of Science][Medline].
-
Bickford ME,
Van Horn SC,
Sherman SM
(1992)
Retinal Y axons contact interneurons in the lateral geniculate nucleus of the cat.
Soc Neurosci Abstr
18:141.
-
Campbell MJ,
Morrison JH
(1989)
Monoclonal antibody to neurofilament protein (SMI-32) labels a subpopulation of pyramidal neurons in the human and monkey cortex.
J Comp Neurol
282:191-205[Web of Science][Medline].
-
Carmichael ST,
Price JL
(1994)
Architectonic subdivision of the orbital and prefrontal cortex in the macaque monkey.
J Comp Neurol
346:366-402[Web of Science][Medline].
-
Chaudhuri A,
Zangenehpour S,
Matsubara JA,
Cynader MS
(1996)
Differential expression of neurofilament protein in the visual system of the vervet monkey.
Brain Res
709:17-26[Web of Science][Medline].
-
Cusick CG,
Seltzer B,
Cola M,
Griggs E
(1995)
Chemoarchitectonics and corticocortical terminations within the superior temporal sulcus of the rhesus monkey: evidence for subdivisions of superior temporal polysensory cortex.
J Comp Neurol
360:513-535[Web of Science][Medline].
-
del Rio MR,
Defelipe J
(1994)
A study of SMI-32-stained pyramidal cells, parvalbumin-immunoreactive chandelier cells, and presumptive thalamocortical axons in the human temporal neocortex.
J Comp Neurol
342:389-408[Web of Science][Medline].
-
Drager UC,
Edwards DL,
Barnstable CJ
(1984)
Antibodies against filamentous components in discrete cell types of the mouse retina.
J Neurosci
4:2025-2042[Abstract].
-
Duong T,
Gallagher KA
(1994)
Immunoreactivity patterns in neurofibrillary tangles of the inferior temporal cortex in Alzheimer's disease.
Mol Chem Neuropathol
22:105-122[Medline].
-
Eckert MJ,
Pegado VD,
Duffy KR,
Murphy KM
(1997)
Development of pyramidal neurons in cat visual cortex following normal or monocular visual experience.
Soc Neurosci Abstr
23:2260.
-
Friedlander MJ,
Martin KA
(1991)
Effects of monocular visual deprivation on geniculocortical innervation of area 18 in cat.
J Neurosci
11:3268-3288[Abstract].
-
Friedlander MJ,
Lin C-S,
Stanford LR,
Sherman SM
(1981)
Morphology of functionally identified neurons in lateral geniculate nucleus of the cat.
J Neurophysiol
46:80-129[Free Full Text].
-
Friedlander MJ,
Stanford LR,
Sherman SM
(1982)
Effects of monocular deprivation on the structure-function relationship of individual neurons in the cat's lateral geniculate nucleus.
J Neurosci
2:321-330[Abstract].
-
Gabriel R,
Straznicky C
(1992)
Immunocytochemical localization of parvalbumin and neurofilament triplet protein immunoreactivity in the cat retina: colocalization in a subpopulation of AII amacrine cells.
Brain Res
595:133-136[Web of Science][Medline].
-
Gai WP,
Vickers JC,
Blumbergs PC,
Blessing WW
(1994)
Loss of non-phosphorylated neurofilament immunoreactivity, with preservation of tyrosine hydroxylase, in surviving substantia nigra neurons in Parkinson's disease.
J Neurol Neurosurg Psychiatry
57:1039-1046[Abstract/Free Full Text].
-
Garraghty PE,
Sur M,
Sherman SM
(1986)
The role of competitive mechanisms in the postnatal development of X and Y retinogeniculate axons.
J Comp Neurol
251:198-215[Web of Science][Medline].
-
Garraghty PE,
Shatz CJ,
Stretavan DW,
Sur M
(1988)
Axon arbors of X and Y retinal ganglion cells are differentially affected by prenatal disruption of binocular inputs.
Proc National Acad Sci USA
85:7361-7365[Abstract/Free Full Text].
-
Guillery RW
(1966)
A study of Golgi preparations from the dorsal lateral geniculate nucleus of the adult cat.
J Comp Neurol
128:21-50[Web of Science][Medline].
-
Guillery RW
(1972)
Binocular competition in the control of geniculate cell growth.
J Comp Neurol
144:117-130[Web of Science][Medline].
-
Guillery RW,
Stelzner DJ
(1970)
The differential effects of unilateral lid closure upon the monocular and binocular segments of the dorsal lateral geniculate nucleus in the cat.
J Comp Neurol
139:413-422[Web of Science][Medline].
-
Gutierrez C,
Yuan A,
Cusick CG
(1995)
Neurochemical subdivisions of the inferior pulvinar in macaque monkeys.
J Comp Neurol
363:545-562[Web of Science][Medline].
-
Hamos JE,
Van Horn SC,
Sherman SM
(1986)
Synaptic circuitry of an individual retinogeniculate axon from a retinal Y-cell.
Soc Neurosci Abstr
12:1037.
-
Hamos JE,
Van Horn SC,
Raczkowski D,
Sherman SM
(1987)
Synaptic circuits involving an individual retinogeniculate axon in the cat.
J Comp Neurol
259:165-192[Web of Science][Medline].
-
Hickey TL
(1980)
Development of the dorsal lateral geniculate nucleus in normal and visually deprived cats.
J Comp Neurol
189:467-481[Web of Science][Medline].
-
Hof PR,
Morrison JH
(1990)
Quantitative analysis of a vulnerable subset of pyramidal neurons in Alzheimer's disease. II. Primary and secondary visual cortex.
J Comp Neurol
301:55-64[Web of Science][Medline].
-
Hof PR,
Morrison JH
(1995)
Neurofilament protein defines regional patterns of cortical organization in the macaque monkey visual system: a quantitative immunohistochemical analysis.
J Comp Neurol
352:161-186[Web of Science][Medline].
-
Hof PR,
Cox K,
Morrison JH
(1990)
Quantitative analysis of a vulnerable subset of pyramidal neurons in Alzheimer's disease. I. Superior frontal and inferior temporal cortex.
J Comp Neurol
301:44-54[Web of Science][Medline].
-
Hof PR,
Nimchinsky EA,
Morrison JH
(1995)
Neurochemical phenotype of corticocortical connections in the macaque monkey: quantitative analysis of a subset of neurofilament protein-immunoreactive projection neurons in frontal, parietal, temporal, and cingulate cortices.
J Comp Neurol
362:109-133[Web of Science][Medline].
-
Humphrey AL,
Sur M,
Uhlrich DJ,
Sherman SM
(1985a)
Projection patterns of individual X- and Y-cell axons from the lateral geniculate nucleus to cortical area 17 in the cat.
J Comp Neurol
233:159-189[Web of Science][Medline].
-
Humphrey AL,
Sur M,
Uhlrich DJ,
Sherman SM
(1985b)
Termination patterns of individual X- and Y-cell axons in the visual cortex of the cat: projections to area 18, to the 17/18 border region, and to both areas 17 and 18.
J Comp Neurol
233:190-212[Web of Science][Medline].
-
Matus A
(1988)
Neurofilament protein phosphorylation
 where, when, and why.
Trends Neurosci
11:291-292[Web of Science][Medline]. -
Murakami DM,
Wilson PD
(1983)
Effects of early monocular deprivation on cells in the C-laminae of the cat lateral geniculate nucleus.
Dev Brain Res
9:353-358.
-
Murakami DM,
Wilson PD
(1987)
The development of soma size changes on cells in the C-laminae of the cat lateral geniculate nucleus following monocular deprivation.
Dev Brain Res
35:215-224.
-
Raczkowski D,
Sherman MS
(1985)
Morphology and physiology of single neurons in the medial interlaminar nucleus of the cat's lateral geniculate nucleus.
J Neurosci
5:2702-2718[Abstract].
-
Shatz CJ,
Stryker MP
(1978)
Ocular dominance in layer IV of the cat's visual cortex and the effects of monocular deprivation.
J Physiol (Lond)
281:267-283[Abstract/Free Full Text].
-
Sherman SM
(1985)
Functional organization of the W-, X-, and Y-cell pathways in the cat: a review and hypothesis.
In: Progress in psychobiology and physiological psychology, Vol II (Sprague JM,
Epstein AN,
eds), pp 233-314. New York: Academic.
-
Sherman SM,
Spear PD
(1982)
Organization of visual pathways in normal and visually deprived cats.
Physiol Rev
62:738-855[Free Full Text].
-
Sherman SM,
Wilson JR,
Guillery RW
(1975)
Evidence that binocular competition affects the postnatal development of Y-cells in the cat's lateral geniculate nucleus.
Brain Res
100:441-444[Web of Science][Medline].
-
Smith MC,
Mallory M,
Hansen LA,
Ge N,
Masliah E
(1995)
Fragmentation of the neuronal cytoskeleton in the Lewy body variant of Alzheimer's disease.
NeuroReport
6:673-676[Medline].
-
Spear PD,
McCall MA,
Tumosa N
(1989)
W- and Y-cells in the C layers of the cat's lateral geniculate nucleus: normal properties and effects of monocular deprivation.
J Neurophysiol
61:58-73[Abstract/Free Full Text].
-
Sternberger NH,
Sternberger LA,
Ulrich J
(1985)
Aberrant neurofilament phosphorylation in Alzheimer disease.
Proc National Acad Sci USA
82:4274-4276[Abstract/Free Full Text].
-
Straznicky C,
Vickers JC,
Gabriel R,
Costa M
(1992)
A neurofilament protein antibody selectively labels a large ganglion cell type in the human retina.
Brain Res
582:123-128[Web of Science][Medline].
-
Su JH,
Cummings BJ,
Cotman CW
(1996)
Plaque biogenesis in brain aging and Alzheimer's disease. I. Progressive changes in phosphorylation states of paired helical filaments and neurofilaments.
Brain Res
739:79-87[Web of Science][Medline].
-
Sur M,
Humphrey AL,
Sherman SM
(1982)
Monocular deprivation affects X- and Y-cell retinogeniculate terminations in cats.
Nature
300:183-185[Medline].
-
Sur M,
Weller RE,
Sherman SM
(1984)
Development of X- and Y-cell retinogeniculate terminations in kittens.
Nature
310:246-249[Medline].
-
Troncoso JC,
Sternberger LA,
Sternberger NH,
Hoffman PN,
Price DL
(1986)
Immunocytochemical studies of neurofilament antigens in the neurofibrillary pathology induced by aluminum.
Brain Res
364:295-300[Medline].
-
Vickers JC,
Delacourte A,
Morrison JH
(1992)
Progressive transformation of the cytoskeleton associated with normal aging and Alzheimer's disease.
Brain Res
594:273-278[Web of Science][Medline].
-
Wible BA,
Smith KE,
Anglelides KJ
(1989)
Resolution and purification of a neurofilament-specific kinase.
Proc National Acad Sci USA
568:209-218.
-
Wiesel TN,
Hubel DH
(1963)
Effects of visual deprivation on morphology and physiology of cells in the cat's lateral geniculate body.
J Neurophysiol
26:978-993[Free Full Text].
-
Wilson JR,
Friedlander MJ,
Sherman SM
(1984)
Fine structural morphology of identified X- and Y-cells in the cat's lateral geniculate nucleus.
Proc R Soc Lond [Biol]
221:411-436[Medline].
-
Xiao J,
Montiero MJ
(1994)
Identification and characterization of a novel (115 kDa) neurofilament-associated kinase.
J Neurosci
14:1820-1833[Abstract].
-
Yoshioka T
(1997)
Differential regulation of neurofilament triplet proteins under monocular deprivation in adult macaque V1.
Soc Neurosci Abstr
23:1664.
Copyright © 1998 Society for Neuroscience 0270-6474/98/18166549-09$05.00/0
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Abstract
Introduction
