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1.
Vitanova L 《Cellular and molecular neurobiology》2007,27(4):407-421
Summary 1. Glutamate is one of the main neurotransmitters in the retina. Its effects are mediated by a large number of ionotropic
and metabotropic receptors.
2. The distribution of ionotropic AMPA receptor subunits GluR1–4, kainate receptor subunits GluR5–7 and KA2, as well as delta
receptors 1–2 was studied in turtle retina. Indirect immunofluorescence was used to localize the different receptor subunits
viewed using light microscopy.
3. Results show that all subunits, with excerption of GluR1 and GluR5, are widely distributed in the turtle retina.
4. They are mainly located in the both plexiform layers of the retina where punctate staining, a sign for synaptic localization,
is observed.
5. The vast majority of the subunits possess specific pattern of staining that allow to suppose that they are involved in
different retinal circuits.
6. It can be assumed that the GluR2/3 and GluR6/7 subunits are expressed on the dendrites of a subpopulation of bipolar cells
that are immunopositive for α-isoform of protein kinase C (PKCα). The GluR2/3 and GluR6/7 subunits are most probably used
by the same PKCα immunopositive bipolar cells in their synaptic contacts with the third-order retinal neurons, the amacrine
and ganglion cells. 相似文献
2.
Localization of metabotropic glutamate receptors in the outer plexiform layer of the goldfish retina
We studied the localization of metabotropic glutamate receptors (mGluRs) in the goldfish outer plexiform layer by light-and
electron-microscopical immunohistochemistry. The mGluR1α antibody labeled putative ON-type bipolar cell dendrites and horizontal
cell processes in both rod spherules and cone triads. Immunolabeling for mGluR2/3 was absent in the rod synaptic complex but
was found at horizontal cell dendrites directly opposing the cone synaptic ribbon. The mGluR5 antibody labeled Müller cell
processes wrapping rod terminals and horizontal cell somata. The mGluR7 antibody labeled mainly horizontal cell dendrites
invaginating rods and cones and some putative bipolar cell dendrites in the cone synaptic complex. The finding of abundant
expression of various mGluRs in bipolar and horizontal cell dendrites suggests multiple sites of glutamatergic modulation
in the outer retina.
Financial support for this work was provided by Conselho Nacional de Pesquisa (CNPq), Brazil (grant 200915/98-3 to C.J.) 相似文献
3.
In-Beom Kim Mun-Yong Lee S.-J. Oh Keun-Young Kim M.-H. Chun 《Cell and tissue research》1998,292(1):17-25
The synaptic connectivity between rod bipolar cells and GABAergic neurons in the inner plexiform layer (IPL) of the rat retina was studied using two immunocytochemical markers. Rod bipolar cells were stained with an antibody specific for protein kinase C (PKC, α isoenzyme), and GABAergic neurons were stained with an antiserum specific for glutamic-acid decarboxylase (GAD). Some amacrine cells were also labeled with the anti-PKC antiserum. All PKC-labeled amacrine cells examined showed GABA immunoreactivity, indicating that PKC-labeled amacrine cells constitute a subpopulation of GABAergic amacrine cells in the rat retina. A total of 150 ribbon synapses established by rod bipolar cells were observed in the IPL. One member of the postsynaptic dyads was always an unlabeled AII amacrine cell process, and the other belonged to an amacrine-cell process showing GAD immunoreactivity. The majority (n=92) (61.3%) of these processes made reciprocal synapses back to the axon terminals of rod bipolar cells. In addition, 78 conventional synapses onto rod bipolar axons were observed, and among them 52 (66.7%) were GAD-immunoreactive. Thus GABA provides the major inhibitory input to rod bipolar cells. 相似文献
4.
Zhong Huang Robert E. Anderson Wei Cao Allan F. Wiechmann Raju V. S. Rajala 《Neurochemical research》2011,36(4):627-635
Type II phosphatidylinositol 5-phosphate 4-kinase (PIPKIIα) catalyzes the synthesis of phosphatidylinositol-4,5-bisphosphate
(PI-4,5-P2), an essential lipid second messenger that may be involved in the regulation of phototransduction, neuroprotection, and morphogenesis
in the vertebrate retina. Here we report that in rodent and transgenic frogs, the light-mediated activity and membrane binding
of PIPKIIα in rod outer segments (ROS) is dependent on tyrosine phosphorylation of ROS proteins. The greater type II α PIP
kinase activity in the light-adapted ROS membrane results from light-driven translocation of PIPKIIα from the rod inner segment
to ROS, and subsequent binding to the ROS membrane, thus improving access of the kinase to its lipid substrates. These results
indicate a novel mechanism of light regulation of the PIPKIIα activity in photoreceptors, and suggest that the greater PIPKIIα
activity in light-adapted animals and the resultant accumulation of PI-4,5-P2 within the ROS membrane may be important for the function of photoreceptor cells. 相似文献
5.
《Journal of Ultrastructure and Molecular Structure Research》1989,102(1):39-46
Cones are connected to bipolar cells connected to rods by processes extending laterally from the cone terminals (Sjöstrand, 1958). The cone connections have been studied further in the rabbit retina. Structurally these connections are typical synaptic connections. It can be deduced that these connections must affect the on responses of bipolar cells connected to rods in such a way that spatial brightness contrast is enhanced. The connections raise the threshold for rod vision and slow down the changes in the membrane potential of on-bipolar cells. These effects offer an explanation for the duplicity of vision. 相似文献
6.
H. Ueda Takeshi Baba Nobuo Terada Yasuko Kato Shigeo Tsukahara Shinichi Ohno 《Histochemistry and cell biology》1997,108(3):243-248
It is known that the retina contains the protein dystrophin in the ribbon synapse, but the ultrastructural analysis is not
yet fully elucidated. Our previous study reported that dystrophin is localized under the rod cell membranes in rat retinas.
In the present study, we have investigated the relationship between dystrophin-rich regions of rod cell membranes and other
neuronal processes in mouse retinas with a monoclonal antibody raised against the human dystrophin C-terminus. Immunoblotting,
immunofluorescence stainings, and immunoelectron microscopy were employed. Immunoblotting analysis indicated that mouse retinas
possessed some of the dystrophin isoforms of approximately 260 kDa, 140 kDa, and 70 kDa molecular weight. Confocal images
showed a punctate appearance in the outer plexiform layer, as previously described. Immunoelectron microscopy showed that
dystrophin immunoreactive products were always observed at submembranous dense regions of the rod spherule abutting bipolar
processes. These results suggest that retinal dystrophin may be closely involved in signal transmission from rods to bipolar
cells.
Accepted: 7 May 1997 相似文献
7.
Recently, we reported the existence of AII "rod" amacrine cells in the retina of the greater horseshoe bat Rhinolophus ferrumequinum (Jeon et al., 2007). In order to enhance our understanding of bat vision, in the present study, we report on a quantitative analysis of cone and rod photoreceptors. The average cone density was 9,535 cells/mm2, giving a total number of cones of 33,538 cells/retina. The average rod density was 368,891 cells/mm2, giving a total number of rods of 1,303,517 cells. On average, the total populations of rods were 97.49%, and cones were 2.51% of all the photoreceptors. Rod: cone ratios ranged from 33.85:1 centrally to 42.26:1 peripherally, with a mean ratio of 38.96:1. The average regularity index of the cone mosaic in bat retina was 3.04. The present results confirm the greater horseshoe bat retina to be strongly rod-dominated. The rod-dominated retina, with the existence of AII cells discovered in our previous study, strongly suggests that the greater horseshoe bat retina has a functional scotopic property of vision. However, the existence of cone cells also suggests that the bat retina has a functional photopic property of vision. 相似文献
8.
Sillman AJ Dahlin DA 《Journal of experimental zoology. Part A, Comparative experimental biology》2004,301(8):674-681
Retinal whole-mount preparations from the eyes of the North American paddlefish, Polyodon spathula, were examined with a combination of bright field and differential interference contrast microscopy. The entire retina was mapped and population counts of rod and cone photoreceptors were made at regular intervals throughout the retina. The retina is dominated by rods, but a significant percentage (ca. 38%) of the photoreceptors are cones. Mean cone packing density for the entire retina is 6,402+/-1,216 cones/mm2. There is a small (16%) but statistically significant difference between cone packing density in the dorsal retina (6,674+/-1,168 cones/mm2) and the ventral retina (5,745+/-1,076 cones/mm2). There is no region of unusually high cone concentration that might be construed as a fovea or a visual streak. Mean rod packing density for the entire retina is 10,271+/-1,205 rods/mm2. Except in the far periphery, where rods are less numerous, the density of rods is fairly uniform throughout the retina. The data are discussed with regard to paddlefish habitat and behavior. 相似文献
9.
10.
Sampath AP Strissel KJ Elias R Arshavsky VY McGinnis JF Chen J Kawamura S Rieke F Hurley JB 《Neuron》2005,46(3):413-420
Vision in dim light requires that photons absorbed by rod photoreceptors evoke signals that reliably propagate through the retina. We investigated how a perturbation in rod physiology affects propagation of those signals in the retina and ultimately visual sensitivity. Recoverin is a protein in rods that prolongs phototransduction and enhances visual sensitivity. It is not present in neurons postsynaptic to rods, yet we found that light-evoked responses of rod bipolar and ganglion cells were shortened when measured in recoverin-deficient retinas. Unexpectedly, the effect of recoverin on postsynaptic signals could not be explained by its effect on phototransduction. Instead, it is an effect of recoverin downstream of phototransduction in rods that prolongs signal transmission and enhances visual sensitivity. An important implication of our findings is that the recovery phase of the rod photoresponse does not contribute significantly to visual sensitivity near absolute threshold. 相似文献
11.
The localization and immunochemical identification of the novel protein kinase C ϕ (nPKC ϕ) and the atypical protein kinase
C λ (aPKC λ) isoforms in retinas of different species were analyzed by immunohistochemistry and SDS-PAGE/Western blotting.
nPKC ϕ immunoreactivity is associated with bipolar cells of mammalian (rabbit, rat and guinea pig) retinas but not the non-mammalian
goldfish retina which has a lower concentration of nPKC ϕ. However, SDS-PAGE and Western blotting data indicate the antigen
recognized by the nPKC ϕ monoclonal antibody in the retina is of a lower molecular weight than that expected for nPKC ϕ. This
would suggest nPKC ϕ is more susceptible to degradation/breakdown than other PKC isoforms found in the retina or that the
nPKC ϕ antibody may be recognizing an unknown retinal antigen. A comparison of nPKC ϕ and nPKC ϕ is present in the developing
retina at an earlier stage than cPKC α. The typical ‘transport’ of cPKC α toward axonal terminals by phorbol-12,13-dibutyrate
does not occur for nPKC ϕ yet both are translocated from the cytosolic to membrane compartments. The inner plexiform layer
and the inner nuclear layer (putative horizontal cells) of all species examined (rabbit, rat, guinea pig and goldfish) exhibited
positive immunoreactivity for aPKC λ as confirmed by SDS-PAGE/Western blotting.
Special issue dedicated to Dr. Kinya Kuriyama. 相似文献
12.
Ji Young Kim Hyun Joon Sohn Eun Young Lee Yong Sook Goo Dong Woon Kim Je Hoon Seo 《Neurochemical research》2011,36(1):76-82
Peripapillary glial cells (PPGCs) are a peculiar macroglia in avian species, located in the central retina adjacent to the
optic nerve head. PPGCs have a similar shape and orientation to Müller cells, which traverse the entire layer of the retina;
however, there are differences in protein expression between the two cell types. In the present study, we first demonstrated
that PPGCs expressed αB-crystallin, which is not expressed in Müller cells, during retinal development. αB-crystallin was
first faintly expressed in PPGCs of the E5 retina, adjacent to the optic nerve head. Further, αB-crystallin was exclusively
expressed in PPGCs up to E14. The shape of these cells was bipolar with vitread and ventricular processes. The vitread processes
of αB-crystallin+ PPGCs became finer at E18. Double labeling analysis clearly demonstrated that only vimentin+ or GFAP+ astrocytes
were located in the optic nerve head and were demarcated from the retina by αB-crystallin+ PPGCs. Furthermore, we determined
that αB-crystallin+ PPGCs, with a number of processes, completely wrapped the optic nerve head and were densely located in
the junction of the optic nerve head and the retina in a whole mount preparation and in vertical-sectioned retinae. The results
of present study, together with reports that retinal astrocytes migrate from the optic nerve head, suggest that PPGCs prevent
astrocytes from migrating into the retina in avian species. 相似文献
13.
The structure of light- and dark-adapted retina of the black bass, Micropterus salmoides has been studied by light and electron microscopy. This retina lacks blood vessels at all levels. The optic fiber layer is divided into fascicles by the processes of Müller cells and the ganglion cell layer is represented by a single row of voluminous cells. The inner nuclear layer consists of two layers of horizontal cells and bipolar, amacrine and interplexiform cells. In the outer plexiform layer we observed the synaptic terminals of photoreceptor cells, rod spherules and cone pedicles and terminal processes of bipolar and horizontal cells. The spherules have a single synaptic ribbon and the pedicles possess multiple synaptic ribbons. Morphologically, we have identified three types of photoreceptors: rods, single cones and equal double cones which undergo retinomotor movements in response to changes in light conditions. The cones are arranged in a square mosaic whereas the rods are dispersed between the cones. 相似文献
14.
Hu K 《Bulletin of mathematical biology》2007,69(3):1019-1030
Supercoiling of a closed circular DNA rod may result from an application of terminal twist to the DNA rod by cutting the rod,
rotating one of the cut faces as the other being fixed and then sealing the cut. According to White's formula, DNA supercoiling
is probably accompanied by a writhe of the DNA axis. Deduced from the elastic rod model for DNA structure, an intrinsically
straight closed circular DNA rod does not writhe as subject to a terminal twist, until the number of rotation exceeds a rod-dependent
threshold. By contrast, a closed circular DNA rod with intrinsic curvature writhes instantly as subject to a terminal twist.
This noteworthy character in fact belongs to many intrinsically curved DNA rods. By solving the dynamic equations, the linearization
of the Euler–Lagrange equations governing intrinsically curved DNA rods, this paper shows that almost every clamped-end intrinsically
curved DNA rod writhes instantly when subject to a terminal twist (clamped-end DNA rods include closed circular DNA rods and
topological domains of open DNA rods). In terms of physical quantities, the exceptions are identified with points in ℝ6 whose projections onto ℝ5 (through ignoring the total energy density of a rod) form a subset of a quadratic hypersurface. This paper also suggests
that the terminal twist induced writhe is due to the elasticity and the clamped-end boundary conditions of the DNA rods.
To my sister for her 50th birthday. 相似文献
15.
David V. Pow 《Cell and tissue research》1994,278(2):311-326
The morphology of the retina of the Australian lungfish Neoceratodus forsteri was investigated by means of light- and electron microscopy, whilst immunocytochemical studies were performed to determine the cellular distributions of the major amino acid neurotransmitters and other amino acids. The distributions of glycine and GABA were similar to those previously described for teleost, amphibian and mammalian retinae. Labelling was abundant in amacrine cells, whilst GABA was also present in one layer of horizontal cells and some bipolar cells. Taurine was present in both rods and cones, but, unlike the mammalian or avian retina, was absent from other cellular structures, including glial elements. Unexpectedly, the photoreceptor terminals lacked an apparent content of the excitatory amino acid transmitter glutamate. The glutamate that was present in the rods and cones occupied a crescentic arc corresponding to the location of glycogen-rich paraboloids. Asparagine was also present in rods, albeit in the modified mitochondria that formed the elipsoids of the rod inner segments. Arginine, the precursor for formation of nitric oxide, was present in glial cells, and in the paraboloids of both rods and cones. 相似文献
16.
Mosaics of photoreceptors, and horizontal and bipolar cells of the Xenopus laevis retina were studied in whole-mount preparations applying lectin-cytochemical, immunocytochemical and intracellular labeling techniques. The combined density of all photoreceptor types was about 13700/mm2, of which rods represented 53%. Of the cones, the large long-wavelength-sensitive (86% of all cones) and the miniature ultraviolet-wavelength-sensitive (4%) ones could be labeled with peanut agglutinin, whereas the large short-wavelength-sensitive (10%) cones remained unlabeled. There were no significant regional differences in photoreceptor distribution. Bipolar cells were selectively labeled with antibodies against calretinin. Their density was between 4000 and 6000 cells/cm2, with slightly elevated numbers in the superior nasal quadrant. Two types of horizontal cell were injected intracellularly. The luminosity-type cells were more frequent (approximately 1000 cells/mm2) than the chromaticity cells (approximately 450 cells/mm2). The dendritic field size of the latter cell type was threefold bigger than that of the luminosity cells. The coverage factors were estimated to be 3.3 for the luminosity cells and 5.2 for the chromaticity cells. The luminosity cells contacted all photoreceptor types, whereas chromatic horizontal cells received their inputs from the short-wavelength-sensitive cones and from some, but not all, rods. Luminosity cells encounter about 50-60 potential synaptic partners within their dendritic fields, whereas chromatic horizontal cells only about 20. Chromatic horizontal cells form multiple synaptic contacts with the short-wavelength-sensitive cones. The results indicate that the overall photoreceptor to bipolar and bipolar to ganglion cell convergence in Xenopus retina is similar to that in the central retinal specialized regions of mammals, predicting comparable spatial resolutions. 相似文献
17.
The carp retina was examined by NADPH diaphorase histochemistry to determine if the staining pattern of retinal cells was changed depending on the adaptation state of the retina. When dark-adapted for 5 h, ellipsoids of inner segments of both rods and cones and some horizontal cells were heavily stained. Staining was also found in subpopulations of amacrine cells and ganglion cells. In addition, Muller cells were strongly positive for NADPH diaphorase. When light-adapted for 5h, ellipsoids of photoreceptors and ganglion cells were less intensely stained, whereas Muller cells and horizontal cells became negative for NADPH diaphorase. Furthermore, rod ON-center bipolar cells were clearly stained. The difference of staining of amacrine cells between dark- and light-adapted retinas was not significant. The differences in diaphorase-staining pattern between dark- and light-adapted retinas suggest that Muller cells, some horizontal cells and rod ON-center bipolar cells contain inducible nitric oxide synthase, 相似文献
18.
Light stimulates dopamine release in the retina and has been shown to rapidly up-regulate rod opsin mRNA. In the present study, we tested the effect of dopamine on rod opsin mRNA expression and examined the hypothesis that dopamine can mediate a light-evoked increase in opsin gene expression. Northern blots showed that a 30-min light-exposure increased rod opsin mRNA expression 27%. In situ hybridization on isolated rods showed that 500 nM dopamine and 1 microM quinpirole (dopamine D2/D3/D4 agonist) increased opsin mRNA 45% and 26%, respectively. The effect of quinpirole was selectively blocked by the D4 antagonist, L750,667 (20 microM). In very low density cultures, quinpirole increased opsin expression 46%, suggesting a direct effect on rod photoreceptors. Consistent with a dopamine D4 receptor mechanism, 1 microM H-89 (protein kinase A inhibitor) increased opsin mRNA 39%. Finally, intravitreal injection of quinpirole increased opsin mRNA 21% whereas injection of L750,667 (10 microM) blocked the light-evoked increase in opsin expression. These data show that rod opsin mRNA is up-regulated by dopamine binding a D4-like receptor on rods, possibly through inhibition of protein kinase A, and that endogenous dopamine can mediate the light-evoked increase in opsin mRNA expression. 相似文献
19.
N Usuda Y Kong M Hagiwara C Uchida M Terasawa T Nagata H Hidaka 《The Journal of cell biology》1991,112(6):1241-1247
We report the immunohistochemical localization of protein kinase C isozymes (types I, II, and III) in the rabbit retina using the monospecific monoclonal antibodies MC-1a, MC-2a, and MC-3a. Using immunoblot analysis of partially purified protein kinase C preparations of rabbit retina, types II and III isozymes alone were detected. The activity of type III was the stronger. By light microscopic immunohistochemical analysis, retinal neurons were negative for type I and positive for type II and type III isozymes. Type II was more diffusely distributed through the retinal layers, but was distinctive in ganglion cells, bipolar cells, and outer segments. The immunoreactivity was stronger for type III isozyme, and it was observed in mop (rod) bipolar cells and amacrine cells. By using immunoelectron microscopy, the cytoplasm of the cell body, the axon, and dendrites of the mop bipolar cells were strongly immunoreactive for type III. The so-called rod bipolar cells were for the first time seen to form synapses with rod photoreceptor cells. These differential localizations of respective isozymes in retinal neurons suggest that each isozyme has a different site of function in each neuron. 相似文献
20.
Green sturgeon and pallid sturgeon photoreceptors were studied with scanning electron microscopy (SEM), microspectrophotometry
and, in the case of the green sturgeon, retinal whole-mounts. The retinas of both species contain both rods and cones: cones
comprise between 23% (whole-mount) and 36% (SEM) of the photoreceptors. The cone population of both species is dominated by
large single cones, but a rare small single cone is also present. In both species, most rods have long outer segments of large
diameter. A rod with a relatively thin outer segment is present in the pallid sturgeon retina. Mean cone packing density for
the entire green sturgeon retina is 4,690±891 cones/mm2, with the dorsal retina 14% more dense than the ventral. There is evidence for a horizontal visual streak just above and
including the optic disc. Mean rod packing density is 16,006±1,668 rods/mm2 for the entire retina, and fairly uniform throughout. Both species have rods with peak absorbance near 540 nm, as well as
short-wavelength-sensitive cones (green: 464.5±0.7 nm; pallid: 439.7±3.5 nm); middle-wavelength-sensitive cones (green: 538.0±1.4 nm;
pallid: 537.0±1.7 nm); and long-wavelength-sensitive cones (green: 613.9±3.0 nm; pallid: 617.8±7.6 nm). 相似文献