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Anti-Opsin, Red/Green antibody

RRID:AB_177456

Antibody ID

AB_177456

Target Antigen

Opsin Red/Green h, m, mk, non-human primate

Proper Citation

(Millipore Cat# AB5405, RRID:AB_177456)

Clonality

polyclonal antibody

Comments

seller recommendations: IH(P); Immunohistochemistry; Consolidated with RRID: AB_11212667 by curator 09/27/2017

Host Organism

rabbit

Vendor

Millipore

Immunohistochemical Procedures for Characterizing the Retinal Expression Patterns of Cre Driver Mouse Lines.

  • Lu Q
  • Methods Mol. Biol.
  • 2018 Apr 26

Literature context:


Abstract:

The retina is a thin neural tissue sitting on the backside of the eye, composed of light-sensing cells, interneurons, and output ganglion neurons. The latter send electrical signals to higher visual centers in the brain. Transgenic mouse lines are becoming one of the most valuable mammalian animal models for the study of visual signal processing within the retina. Especially, the generation of Cre recombinase transgenic mouse lines provides a powerful tool for genetic manipulation. A key step for the utilization of transgenic lines is the characterization of their transgene expression patterns in the retina. Here we describe a standard protocol for characterizing the expression pattern of the Cre recombinase or fluorescent proteins in the retina with an immunohistochemical approach.

Local Signals in Mouse Horizontal Cell Dendrites.

  • Chapot CA
  • Curr. Biol.
  • 2017 Dec 4

Literature context:


Abstract:

The mouse retina contains a single type of horizontal cell, a GABAergic interneuron that samples from all cone photoreceptors within reach and modulates their glutamatergic output via parallel feedback mechanisms. Because horizontal cells form an electrically coupled network, they have been implicated in global signal processing, such as large-scale contrast enhancement. Recently, it has been proposed that horizontal cells can also act locally at the level of individual cone photoreceptors. To test this possibility physiologically, we used two-photon microscopy to record light stimulus-evoked Ca2+ signals in cone axon terminals and horizontal cell dendrites as well as glutamate release in the outer plexiform layer. By selectively stimulating the two mouse cone opsins with green and UV light, we assessed whether signals from individual cones remain isolated within horizontal cell dendritic tips or whether they spread across the dendritic arbor. Consistent with the mouse's opsin expression gradient, we found that the Ca2+ signals recorded from dendrites of dorsal horizontal cells were dominated by M-opsin and those of ventral horizontal cells by S-opsin activation. The signals measured in neighboring horizontal cell dendritic tips varied markedly in their chromatic preference, arguing against global processing. Rather, our experimental data and results from biophysically realistic modeling support the idea that horizontal cells can process cone input locally, extending the classical view of horizontal cell function. Pharmacologically removing horizontal cells from the circuitry reduced the sensitivity of the cone signal to low frequencies, suggesting that local horizontal cell feedback shapes the temporal properties of cone output.

Funding information:
  • NIAID NIH HHS - AI097333(United States)

The formation of the light-sensing compartment of cone photoreceptors coincides with a transcriptional switch.

  • Daum JM
  • Elife
  • 2017 Nov 6

Literature context:


Abstract:

High-resolution daylight vision is mediated by cone photoreceptors. The molecular program responsible for the formation of their light sensor, the outer segment, is not well understood. We correlated daily changes in ultrastructure and gene expression in postmitotic mouse cones, between birth and eye opening, using serial block-face electron microscopy (EM) and RNA sequencing. Outer segments appeared rapidly at postnatal day six and their appearance coincided with a switch in gene expression. The switch affected over 14% of all expressed genes. Genes that switched off were rich in transcription factors and neurogenic genes. Those that switched on contained genes relevant for cone function. Chromatin rearrangements in enhancer regions occurred before the switch was completed, but not after. We provide a resource comprised of correlated EM, RNAseq, and ATACseq data, showing that the growth of a key compartment of a postmitotic cell involves an extensive switch in gene expression and chromatin accessibility.

Study of retinal neurodegeneration and maculopathy in diabetic Meriones shawi: A particular animal model with human-like macula.

  • Hammoum I
  • J. Comp. Neurol.
  • 2017 Sep 1

Literature context:


Abstract:

The purpose of this work was to evaluate a potentially useful animal model, Meriones shawi (M.sh)-developing metabolic X syndrome, diabetes and possessing a visual streak similar to human macula-in the study of diabetic retinopathy and diabetic macular edema (DME). Type 2 diabetes (T2D) was induced by high fat diet administration in M.sh. Body weights, blood glucose levels were monitored throughout the study. Diabetic retinal histopathology was evaluated 3 and 7 months after diabetes induction. Retinal thickness was measured, retinal cell types were labeled by immunohistochemistry and the number of stained elements were quantified. Apoptosis was determined with TUNEL assay. T2D induced progressive changes in retinal histology. A significant decrease of retinal thickness and glial reactivity was observed without an increase in apoptosis rate. Photoreceptor outer segment degeneration was evident, with a significant decrease in the number of all cones and M-cone subtype, but-surprisingly-an increase in S-cones. Damage of the pigment epithelium was also confirmed. A decrease in the number and labeling intensity of parvalbumin- and calretinin-positive amacrine cells and a loss of ganglion cells was detected. Other cell types showed no evident alterations. No DME-like condition was noticed even after 7 months. M.sh could be a useful model to study the evolution of diabetic retinal pathology and to identify the role of hypertension and dyslipidemia in the development of the reported alterations. Longer follow up would be needed to evaluate the potential use of the visual streak in modeling human macular diseases.

Loss of Tmem30a leads to photoreceptor degeneration.

  • Zhang L
  • Sci Rep
  • 2017 Aug 24

Literature context:


Abstract:

Phosphatidylserine (PS) is asymmetrically distributed between the outer and inner leaflets of the plasma membrane in eukaryotic cells. PS asymmetry on the plasma membrane depends on the activities of P4-ATPases, and disruption of PS distribution can lead to various disease conditions. Folding and transporting of P4-ATPases to their cellular destination requires the β subunit TMEM30A proteins. However, the in vivo functions of Tmem30a remain unknown. To this end, we generated retinal-specific Tmem30a-knockout mice to investigate its roles in vivo for the first time. Our data demonstrated that loss of Tmem30a in mouse cone cells leads to mislocalization of cone opsin, loss of photopic electroretinogram (ERG) responses and loss of cone cells. Mechanistically, Tmem30a-mutant mouse embryonic fibroblasts (MEFs) exhibited diminished PS flippase activity and increased exposure of PS on the cell surface. The broad loss of Tmem30a in adult mice led to a reduced scotopic photoresponse, mislocalization of ATP8A2 to the inner segment and cell body, and increased apoptosis in the retina. Our data demonstrated novel essential roles of Tmem30a in the retina.

Deletion of the Thyroid Hormone-Activating Type 2 Deiodinase Rescues Cone Photoreceptor Degeneration but Not Deafness in Mice Lacking Type 3 Deiodinase.

  • Ng L
  • Endocrinology
  • 2017 Jun 1

Literature context:


Abstract:

Type 2 deiodinase amplifies and type 3 deiodinase depletes levels of the active form of thyroid hormone, triiodothyronine. Given the opposing activities of these enzymes, we tested the hypothesis that they counteract each other's developmental functions by investigating whether deletion of type 2 deiodinase (encoded by Dio2) modifies sensory phenotypes in type 3 deiodinase-deficient (Dio3-/-) mice. Dio3-/- mice display degeneration of retinal cones, the photoreceptors that mediate daylight and color vision. In Dio2-/- mice, cone function was largely normal but deletion of Dio2 in Dio3-/- mice markedly recovered cone numbers and electroretinogram responses, suggesting counterbalancing roles for both enzymes in cone survival. Both Dio3-/- and Dio2-/- strains exhibit deafness with cochlear abnormalities. In Dio3-/-;Dio2-/- mice, deafness was exacerbated rather than alleviated, suggesting unevenly balanced actions by these enzymes during auditory development. Dio3-/- mice also exhibit an atrophic thyroid gland, low thyroxine, and high triiodothyronine levels, but this phenotype was ameliorated in Dio3-/-;Dio2-/- mice, indicating counterbalancing roles for the enzymes in determining the thyroid hormone status. The results suggest that the composite action of these two enzymes is a critical determinant in visual and auditory development and in setting the systemic thyroid hormone status.

Funding information:
  • NIDDK NIH HHS - R01 DK095908()

Retinal remodeling in human retinitis pigmentosa.

  • Jones BW
  • Exp. Eye Res.
  • 2017 Jun 15

Literature context:


Abstract:

Retinitis Pigmentosa (RP) in the human is a progressive, currently irreversible neural degenerative disease usually caused by gene defects that disrupt the function or architecture of the photoreceptors. While RP can initially be a disease of photoreceptors, there is increasing evidence that the inner retina becomes progressively disorganized as the outer retina degenerates. These alterations have been extensively described in animal models, but remodeling in humans has not been as well characterized. This study, using computational molecular phenotyping (CMP) seeks to advance our understanding of the retinal remodeling process in humans. We describe cone mediated preservation of overall topology, retinal reprogramming in the earliest stages of the disease in retinal bipolar cells, and alterations in both small molecule and protein signatures of neurons and glia. Furthermore, while Müller glia appear to be some of the last cells left in the degenerate retina, they are also one of the first cell classes in the neural retina to respond to stress which may reveal mechanisms related to remodeling and cell death in other retinal cell classes. Also fundamentally important is the finding that retinal network topologies are altered. Our results suggest interventions that presume substantial preservation of the neural retina will likely fail in late stages of the disease. Even early intervention offers no guarantee that the interventions will be immune to progressive remodeling. Fundamental work in the biology and mechanisms of disease progression are needed to support vision rescue strategies.

Photoreceptor topography and spectral sensitivity in the common brushtail possum (Trichosurus vulpecula).

  • Vlahos LM
  • J. Comp. Neurol.
  • 2014 Oct 15

Literature context:


Abstract:

Marsupials are believed to be the only non-primate mammals with both trichromatic and dichromatic color vision. The diversity of color vision systems present in marsupials remains mostly unexplored. Marsupials occupy a diverse range of habitats, which may have led to considerable variation in the presence, density, distribution, and spectral sensitivity of retinal photoreceptors. In this study we analyzed the distribution of photoreceptors in the common brushtail possum (Trichosurus vulpecula). Immunohistochemistry in wholemounts revealed three cone subpopulations recognized within two spectrally distinct cone classes. Long-wavelength sensitive (LWS) single cones were the largest cone subgroup (67-86%), and formed a weak horizontal visual streak (peak density 2,106 ± 435/mm2) across the central retina. LWS double cones were strongly concentrated ventrally (569 ± 66/mm2), and created a "negative" visual streak (134 ± 45/mm2) in the central retina. The strong regionalization between LWS cone topographies suggests differing visual functions. Short-wavelength sensitive (SWS) cones were present in much lower densities (3-10%), mostly located ventrally (179 ± 101/mm2). A minority population of cones (0-2.4%) remained unlabeled by both SWS- and LWS-specific antibodies, and may represent another cone population. Microspectrophotometry of LWS cone and rod visual pigments shows peak spectral sensitivities at 544 nm and 500 nm, respectively. Cone to ganglion cell convergences remain low and constant across the retina, thereby maintaining good visual acuity, but poor contrast sensitivity during photopic vision. Given that brushtail possums are so strongly nocturnal, we hypothesize that their acuity is set by the scotopic visual system, and have minimized the number of cones necessary to serve the ganglion cells for photopic vision.

Suppression of microglial activation is neuroprotective in a mouse model of human retinitis pigmentosa.

  • Peng B
  • J. Neurosci.
  • 2014 Jun 11

Literature context:


Abstract:

Retinitis pigmentosa (RP) is a photoreceptor-degenerative disease caused by various mutations and is characterized by death of rod photoreceptor cell followed by gradual death of cone photoreceptors. The molecular mechanisms that lead to rod and cone death are not yet fully understood. Neuroinflammation contributes to the progression of many chronic neurodegenerative disorders. However, it remains to be determined how microglia contribute to photoreceptor disruption in RP. In this study, we explored the role of microglia as a contributor to photoreceptor degeneration in the rd10 mouse model of RP. First, we demonstrated that microglia activation was an early alteration in RP retinas. Inhibition of microglia activation by minocycline reduced photoreceptor apoptosis and significantly improved retinal structure and function and visual behavior in rd10 mice. Second, we identified that minocycline exerted its neuroprotective effects through both anti-inflammatory and anti-apoptotic mechanisms. Third, we found that Cx3cr1 deficiency dysregulated microglia activation and subsequently resulted in increased photoreceptor vulnerability in rd10 mice, suggesting that the Cx3cl1/Cx3cr1 signaling pathway might protect against microglia neurotoxicity. We concluded that suppression of neuroinflammatory responses could be a potential treatment strategy aimed at improving photoreceptor survival in human RP.

Unique photoreceptor arrangements in a fish with polarized light discrimination.

  • Novales Flamarique I
  • J. Comp. Neurol.
  • 2011 Mar 1

Literature context:


Abstract:

In contrast to other vertebrates, some anchovies have cone photoreceptors with longitudinally oriented outer segment lamellae. These photoreceptors are axially dichroic (i.e., they are sensitive to the polarization of axially incident light) and form the basis of a polarization detection system in the northern anchovy, Engraulis mordax. Whether other cone types exist in the retina of this animal, and whether multiple cone opsins are expressed in the retinas of anchovies, is unknown. Likewise, a detailed examination of photoreceptor ultrastructure in nondichroic photoreceptors has not been carried out despite its importance to understand visual specializations within the retina and its use in the formulation of models to explain cellular structure. Here, I combined light and electron microscopy with immunohistochemical studies of opsin expression to infer mechanisms of lamellar formation and to evaluate the potential for color vision in the northern anchovy retina. Morphological observations revealed three cone formations: 1) continuous rows made up of alternating long and short (bilobed) cones with longitudinally oriented lamellae that are orthogonal between cone types; 2) continuous rows of alternating long and short cones in which only the short cones have longitudinally oriented lamellae; and 3) rows of triple cones with transversely oriented lamellae, each triple cone consisting of two lateral cones flanking a small central cone. Ultrastructure investigations supported two models of outer segment formation resulting in the longitudinally oriented lamellae of long and short cones. In the case of the long cone, lateral compression of the outer segment, potentially via the formation of guanine platelet stacks in neighboring pigment epithelium cells, results in a shape transformation from conical to cunate and a tilt from transverse to longitudinal lamellae. In the case of the short (bilobed) cone, membrane invaginations from the connecting ciliary structure grow longitudinally to form a dichroic stack. Opsin expression studies indicated that all cones express middle-to-long wavelength opsins, with long and lateral cones possessing a different opsin from that in short and central cones, confirming the potential for color vision. Together with the ultrastructural observations, these results suggest that the unique cone topography in the northern anchovy retina may underlie a visual system with segregated color and polarization detection channels.

Funding information:
  • Canadian Institutes of Health Research - NS 16446(Canada)
  • NHGRI NIH HHS - R01 HG004881(United States)

cGMP-dependent cone photoreceptor degeneration in the cpfl1 mouse retina.

  • Trifunović D
  • J. Comp. Neurol.
  • 2010 Sep 1

Literature context:


Abstract:

Inherited retinal degeneration affecting both rod and cone photoreceptors constitutes one of the leading causes of blindness in the developed world. Such degeneration is at present untreatable, and the underlying neurodegenerative mechanisms are unknown, even though certain genetic causes have been established. The rd1 mouse is one of the best characterized animal models for rod photoreceptor degeneration, whereas the cpfl1 mouse is a recently discovered model for cone cell death. Because both animal models are affected by functionally similar mutations in the rod and cone phosphodiesterase 6 genes, respectively, we asked whether the mechanisms of photoreceptor degeneration in these two mouse lines share common pathways. In the present study, we followed the temporal progression of photoreceptor degeneration in the cpfl1 retina, correlated it with specific metabolic markers, and compared it with the wild-type and the rd1 situation. Similar to corresponding rd1 observations, cpfl1 cone photoreceptor cell death was associated with an accumulation of cyclic guanosine monophosphate (cGMP), activity of calpains, and phosphorylation of vasodilator-stimulated protein (VASP). Cone degeneration progressed rapidly, with a peak in cell death around postnatal day 24. Furthermore, cpfl1 cone photoreceptor migration during early postnatal development was delayed significantly compared with the corresponding wild-type retina. The finding that rod and cone photoreceptor degeneration was associated with the same metabolic markers suggests that in both cell types similar degenerative mechanisms are active. This raises the possibility that equivalent neuroprotective strategies may be used to prevent both rod and cone photoreceptor degeneration.

Funding information:
  • NEI NIH HHS - PN2EY018228(United States)

Neurogenin1 effectively reprograms cultured chick retinal pigment epithelial cells to differentiate toward photoreceptors.

  • Yan RT
  • J. Comp. Neurol.
  • 2010 Feb 15

Literature context:


Abstract:

Photoreceptors are highly specialized sensory neurons in the retina, and their degeneration results in blindness. Replacement with developing photoreceptor cells promises to be an effective therapy, but it requires a supply of new photoreceptors, because the neural retina in human eyes lacks regeneration capability. We report efficient generation of differentiating, photoreceptor-like neurons from chick retinal pigment epithelial (RPE) cells propagated in culture through reprogramming with neurogenin1 (ngn1). In reprogrammed culture, a large number of the cells (85.0% +/- 5.9%) began to differentiate toward photoreceptors. Reprogrammed cells expressed transcription factors that set in motion photoreceptor differentiation, including Crx, Nr2E3, NeuroD, and RXRgamma, and phototransduction pathway components, including transducin, cGMP-gated channel, and red opsin of cone photoreceptors (equivalent to rhodopsin of rod photoreceptors). They developed inner segments rich in mitochondria. Furthermore, they responded to light by decreasing their cellular free calcium (Ca(2+)) levels and responded to 9-cis-retinal by increasing their Ca(2+) levels after photobleaching, hallmarks of photoreceptor physiology. The high efficiency and the advanced photoreceptor differentiation indicate ngn1 as a gene of choice to reprogram RPE progeny cells to differentiate into photoreceptor neurons in future cell replacement studies.

Glycine receptor-mediated synaptic transmission regulates the maturation of ganglion cell synaptic connectivity.

  • Xu HP
  • J. Comp. Neurol.
  • 2008 Jul 1

Literature context:


Abstract:

It is well documented that neuronal activity is required for the developmental segregation of retinal ganglion cell (RGC) synaptic connectivity with ON and OFF bipolar cells in mammalian retina. Our recent study showed that light deprivation preferentially blocked the developmental RGC dendritic redistribution from the center to sublamina a of the inner plexiform layer (IPL). To determine whether OFF signals in visual stimulation are required for OFF RGC dendritic development, the light-evoked responses and dendritic stratification patterns of RGCs in Spastic mutant mice, in which the OFF signal transmission in the rod pathway is largely blocked due to a reduction of glycine receptor (GlyR) expression, were quantitatively studied at different ages and rearing conditions. The dendritic distribution in the IPL of these mice was indistinguishable from wildtype controls at the age of postnatal day (P)12. However, the adult Spastic mutants had altered RGC light-evoked synaptic inputs from ON and OFF pathways, which could not be mimicked by pharmacologically blocking of glycinergic synaptic transmission on age-matched wildtype animals. Spastic mutation also blocked the developmental redistribution of RGC dendrites from the center to sublamina a of the IPL, which mimicked the effects induced by light deprivation on wildtype animals. Moreover, light deprivation of the Spastic mutants had no additional impact on the RGC dendritic distribution and light response patterns. We interpret these results as that visual stimulation regulates the maturation of RGC synaptic activity and connectivity primarily through GlyR-mediated synaptic transmission.

Early afferent signaling in the outer plexiform layer regulates development of horizontal cell morphology.

  • Raven MA
  • J. Comp. Neurol.
  • 2008 Feb 10

Literature context:


Abstract:

The dendritic patterning of retinal horizontal cells has been shown to be specified by the cone photoreceptor afferents. The present investigation has addressed whether this specification is due to visually dependent synaptic transmission in the outer plexiform layer or to some other early, pre-visual, neural activity. Individually labeled horizontal cells from dark-reared mice, as well as from mice carrying a mutation in the Cacna1f gene, which encodes the pore-forming calcium channel subunit Ca(v)1.4, were assessed for various morphological features. The dark-reared mice showed no alteration in any of these features, despite showing a compromised maximal voltage response in the electroretinograms. The retinas of Cacna1f mutant mice, by contrast, showed conspicuous morphological changes that mimicked the effects observed previously in coneless transgenic mice. These changes were present as early as postnatal day 10, when the shape and density of the cone pedicles appeared normal. Ultrastructurally, however, the pedicles at this early stage, as well as in maturity, lacked synaptic ribbons and the invaginations associated with postsynaptic processes. These results suggest a role for this calcium channel subunit in ribbon assembly in addition to its role in modulating calcium influx and glutamate release. Together, they suggest a complex cascade of interactions between developing cone pedicles and horizontal cell dendrites involving early spontaneous activity, dendritic attraction, ribbon assembly, and pedicle invagination.

Funding information:
  • NEI NIH HHS - R01 EY05665(United States)

Transient expression of LIM-domain transcription factors is coincident with delayed maturation of photoreceptors in the chicken retina.

  • Fischer AJ
  • J. Comp. Neurol.
  • 2008 Feb 1

Literature context:


Abstract:

In the retina of warm-blooded vertebrates, photoreceptors are specified many days before the onset of synaptogenesis and the expression of photopigments. The factors that regulate the maturation of photoreceptors in the developing retina remain unknown. We report here that photoreceptors transiently express LIM-domain transcription factors during the development of the chicken retina. We examined the differentiation of photoreceptors through the normal course of embryonic development and at the far periphery of the postnatal retina, where the differentiation of photoreceptors is slowed and persists across a spatial gradient. In the embryonic retina, we find visinin-positive photoreceptors that transiently express Islet2 and Lim3 starting at E8 and ending around E15, but persisting in far peripheral regions of the retina through the first 2 weeks of postnatal development. During early stages of photoreceptor maturation, there is coincident and transient expression of the LIM-domain factors with axonin1, a cell surface glycoprotein that is a member of the immunoglobulin superfamily. Coincident with the downregulation of Islet2 and Lim3, we find the upregulation of calbindin, red/green opsin, rhodopsin, and a synaptic marker in the outer plexiform layer (OPL; dystrophin). In the periphery of the postnatal retina, photoreceptors that express Islet2, Lim3, and axonin1 do not overlap with photoreceptors that express calbindin, red/green opsin, rhodopsin, and dystrophin. We propose that Islet2 and Lim3 may promote the expression of genes that are involved in the early stages of differentiation but may suppress the expression of genes that are required in the mature photoreceptors.

Funding information:
  • NIMH NIH HHS - P50MH103222(United States)

Biocytin wide-field bipolar cells in rabbit retina selectively contact blue cones.

  • MacNeil MA
  • J. Comp. Neurol.
  • 2008 Jan 1

Literature context:


Abstract:

The biocytin wide-field bipolar cell in rabbit retina has a broad axonal arbor in layer 5 of the inner plexiform layer and a wide dendritic arbor that does not contact all cones in its dendritic field. The purpose of our study was to identify the types of cones that this cell contacts. We identified the bipolar cells by selective uptake of biocytin, labeled the cones with peanut agglutinin, and then used antibodies against blue cone opsin and red-green cone opsin to identify the individual cone types. The biocytin-labeled cells selectively contacted cones whose outer segments stained for blue cone opsin and avoided cones that did not. We conclude that the biocytin wide-field bipolar cell is an ON blue cone bipolar cell in the rabbit retina and is homologous to the blue cone bipolar cells that have been previously described in primate, mouse, and ground squirrel retinas.

Funding information:
  • NIMHD NIH HHS - 8G12MD 007603-27(United States)

Heterogeneity of horizontal cells in the chicken retina.

  • Fischer AJ
  • J. Comp. Neurol.
  • 2007 Feb 20

Literature context:


Abstract:

Despite numerous reports that different markers are expressed by horizontal cells in the avian retina, it remains unknown whether different types of horizontal cells can be defined by differences in their immunocytochemical profiles. The purpose of this study was to rectify this deficiency. We identified horizontal cells by indirect immunofluorescence with antibodies to calretinin, trkA, GABA, Prox1, AP2alpha, Pax6, islet1, and Lim1 + 2. We found two major groups of horizontal cells, those that express trkA and those that express calretinin. The trkA-immunoreactive (-IR) horizontal cells had small, round somata and robust, bulbous dendritic endings, whereas calretinin-IR horizontal cells had large, polygonal cell bodies and fine, diffuse dendritic endings, both contacting the calbindin-IR pedicles of double cones. Weak gamma-aminobutyric acid (GABA) immunoreactivity was observed only in a few of the trkA-IR horizontal cells, whereas the overlap of calretinin and GABA immunoreactivities was 100%. The majority of trkA-IR horizontal cells expressed islet1, and the majority of calretinin-IR horizontal cells expressed Lim1 + 2, AP2alpha, and Pax6. Islet1 immunoreactivity was observed in a small fraction of calretinin-IR/non-trkA-IR cells. In agreement with previous reports, we detected Prox1 immunoreactivity in all types of horizontal cells. These immunolabeling profiles suggest that there are four immunochemically distinct subtypes of horizontal cells in the postnatal chick retina, which may match the four types that have been observed in Golgi-impregnated pigeon and turtle retinas.

Funding information:
  • NHGRI NIH HHS - U01 HG004271(United States)