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Heinz Wässle - One of the best experts on this subject based on the ideXlab platform.
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immunocytochemical description of five bipolar cell types of the mouse Retina
The Journal of Comparative Neurology, 2003Co-Authors: Silke Haverkamp, Arlene A Hirano, Krishna K Ghosh, Heinz WässleAbstract:With the ever-growing number of transgenic mice being used in vision research, a precise knowledge of the cellular organization of the mouse Retina is required. As with the cat, rabbit, rat, and primate Retinae, as many as 10 cone bipolar types and one rod bipolar type can be expected to exist in the mouse Retina; however, they still have to be defined. In the current study, several immunocytochemical markers were applied to sections of mouse Retina, and the labeling of bipolar cells was studied using confocal microscopy and electron microscopy. By using antibodies against the neurokinin-3 receptor NK3R; the plasma membrane calcium ATPase1 (PMCA1); and the calcium (Ca)-binding proteins CaB1, CaB5, caldendrin, and recoverin, three different OFF-cone bipolar cells could be identified. One type of ON-cone bipolar cell was identified through its immunoreactivity for CaB5 and PMCA1. Rod bipolar cells, comparable in morphology to those of other mammalian Retinae, expressed protein kinase Cα and CaB5. It was also shown that putative OFF-cone bipolar cells receive light signals through flat contacts at the cone pedicle base, whereas ON-cone bipolar signaling involves invaginating contacts. The distribution of the kainate receptor subunit GluR5 was studied by confocal and electron microscopy. GluR5 was expressed at flat bipolar cell contacts; however, it appears to be involved with only certain types of OFF-cone bipolar cells. This suggests that different bipolar cell types receive their light signals through different sets of glutamate receptors.
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Glycinergic amacrine cells of the rat Retina
The Journal of comparative neurology, 1998Co-Authors: Nicole Menger, David V. Pow, Heinz WässleAbstract:Physiological studies of neurons of the inner Retina, e.g., of amacrine cells, are now possible in a mammalian Retinal slice preparation. The present anatomical study characterizes glycinergic amacrine cells of the rat Retina and thus lays the ground for such future physiological and pharmacological experiments. Rat Retinae were immunolabeled with antibodies against glycine and the glycine transporter-1 (GLYT-1), respectively. Glycine immunoreactivity was found in approximately 50% of the amacrine and 25% of the bipolar cells. GLYT-1 immunoreactivity was restricted to glycinergic amacrine cells. They were morphologically characterized by the intracellular injection of Lucifer Yellow followed by GLYT-1 immunolabeling. Eight different types of glycinergic amacrine cells could be distinguished. They were all small-field amacrine cells with bushy dendritic trees terminating at different levels within the inner plexiform layer. The well-known AII amacrine cell was encountered most frequently. From our measurements of the dendritic field sizes and the density of glycinergic cells, we estimate that there are enough glycinergic amacrine cells available to make sure that all eight types and possibly more tile the Retina regularly with their dendritic fields.
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the synaptic complex of cones in the fovea and in the periphery of the macaque monkey Retina
Vision Research, 1996Co-Authors: Myunghoon Chun, Paul R Martin, Ulrike Grunert, Heinz WässleAbstract:Parallel pathways for visual information processing start at the first synapse of the Retina, at the cone pedicle. At least eight different types of bipolar cells receive direct synaptic input from an individual cone. The present study explores whether enough synaptic sites are available at the cone pedicle to supply all these bipolar cells. Monkey Retinae were optimally fixed for electron microscopy. Serial horizontal sections were cut through the cone pedicle layer in a piece close to the fovea (eccentricity: 0.75 mm) and in a peripheral piece (eccentricity: 5-6 mm). The ribbon synapses (triads) at the cone pedicle base were analysed. The average number of synaptic ribbons per cone pedicle increased from 21.4 +/- 1.6 (n = 26) in central Retina to 41.8 +/- 3 (n = 14) in peripheral Retina. Five central and five peripheral pedicles were reconstructed and the invaginating bipolar cell dendrites forming the central elements of the triads were characterized. Close to the fovea an average of 18 invaginating bipolar cell dendrites was found, in peripheral Retina the average was 90. Pedicles of foveal cones have one invaginating central process per ribbon, pedicles of peripheral cones have two. It is possible that midget bipolar cell dendrites occupy the majority of triads in the fovea, while in peripheral Retina both midget and diffuse bipolar cell dendrites share the triads.
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the rod pathway of the macaque monkey Retina identification of aii amacrine cells with antibodies against calretinin
The Journal of Comparative Neurology, 1995Co-Authors: Heinz Wässle, Ulrike Gruunert, Myungnoon Chun, Brian Blundell BoycottAbstract:AII-amacrine cells were characterized from Golgi-stained sections and wholemounts of the macaque monkey Retina. Similar to other mammalian Retinae, they are narrow-field, bistratified amacrine cells with lobular appendages in the outer half of the inner plexiform layer (IPL) and a bushy, smoother dendritic tree in the inner half. AII cells of the monkey Retina were stained immunocytochemically with antibodies against the calcium-binding protein Calretinin. Their Retinal mosaic was elaborated, and their density distribution across the Retina was measured. Convergence within the rod pathway was calculated. Electron microscopy of Calretinin-immunolabelled sections was used to study the synaptic connections of the AII cells. They receive a major input from rod bipolar cells, and their output is largely onto cone bipolar cells. Thus, the rod pathway of the primate Retina follows the general mammalian scheme as it is known from the cat, the rabbit, and the rat Retina. The spatial sampling properties of macaque AII-amacrine cells are discussed and related to human scotopic visual acuity.© 1995 Wiley-Liss, Inc.
Ahmed A Elmansi - One of the best experts on this subject based on the ideXlab platform.
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visual adaptability and Retinal characterization of the egyptian fruit bat rousettus aegyptiacus pteropodidae new insights into photoreceptors spatial distribution and melanosomal activity
Micron, 2020Co-Authors: Ahmed A Elmansi, M A Alkahtani, K M Alsayyad, E A Ahmed, A R GadAbstract:Our study was conducted to characterize the Retinal structure of the Egyptian fruit bat, Rousettus aegyptiacus to determine the distribution of photoreceptors and melanosomal populations in various Retinal zones. Also, we paid attention to the specific structural and functional adaptations related to their nocturnal habits. We analyzed the Retinae of 12 adult male Egyptian fruit bats using morphometrical, histological, ultrastructural, and immunoblotting standard techniques. Histological findings revealed that the Retinal cells have variations in geometrical architecture and different Retinal thickness together with their corresponding layers bearing specific choroidal papillae projecting towards the inner Retina. Immunoblotting and ultrastructure results showed that the microstructure of the Retina conforms to that pattern found in mammalian species. The Retinal photoreceptors are rod-dominant; alternatively, possess two spectral types of cones: SWS and LW/MWS cones as evidence for the basis for dichromatic vision. In addition, the outer Retina showed densely-distributed melanin granules with a significant increase in the number of pigment epithelium cells in the eccentric Retina. Furthermore, the asymmetric distribution among the Retinal quadrants for the visual pigments of both rods and cones coinciding with neuronal cells such as bipolar and ganglion cells confers instructive information about their visual perception and orientation. In conclusion, our findings indicate that R. aegyptiacus efficiently discriminates colors with complex visual adaptations to mediate increased visual acuity coopted for the nocturnal niches.
Ulrike Janssenbienhold - One of the best experts on this subject based on the ideXlab platform.
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localisation of the putative magnetoreceptive protein cryptochrome 1b in the Retinae of migratory birds and homing pigeons
PLOS ONE, 2016Co-Authors: Petra Bolte, Miriam Liedvogel, Florian Bleibaum, Anja Gunther, Dominik Heyers, Anne Depping, Angelika Einwich, Lars Wohlbrand, Ralf Rabus, Ulrike JanssenbienholdAbstract:Cryptochromes are ubiquitously expressed in various animal tissues including the Retina. Some cryptochromes are involved in regulating circadian activity. Cryptochrome proteins have also been suggested to mediate the primary mechanism in light-dependent magnetic compass orientation in birds. Cryptochrome 1b (Cry1b) exhibits a unique carboxy terminus exclusively found in birds so far, which might be indicative for a specialised function. Cryptochrome 1a (Cry1a) is so far the only cryptochrome protein that has been localised to specific cell types within the Retina of migratory birds. Here we show that Cry1b, an alternative splice variant of Cry1a, is also expressed in the Retina of migratory birds, but it is primarily located in other cell types than Cry1a. This could suggest different functions for the two splice products. Using diagnostic bird-specific antibodies (that allow for a precise discrimination between both proteins), we show that Cry1b protein is found in the Retinae of migratory European robins (Erithacus rubecula), migratory Northern Wheatears (Oenanthe oenanthe) and pigeons (Columba livia). In all three species, Retinal Cry1b is localised in cell types which have been discussed as potentially well suited locations for magnetoreception: Cry1b is observed in the cytosol of ganglion cells, displaced ganglion cells, and in photoreceptor inner segments. The cytosolic rather than nucleic location of Cry1b in the Retina reported here speaks against a circadian clock regulatory function of Cry1b and it allows for the possible involvement of Cry1b in a radical-pair-based magnetoreception mechanism.
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localisation of the putative magnetoreceptive protein cryptochrome 1b in the Retinae of migratory birds and homing pigeons
PLOS ONE, 2016Co-Authors: Petra Bolte, Miriam Liedvogel, Florian Bleibaum, Anja Gunther, Dominik Heyers, Anne Depping, Angelika Einwich, Lars Wohlbrand, Ralf Rabus, Ulrike JanssenbienholdAbstract:Cryptochromes are ubiquitously expressed in various animal tissues including the Retina. Some cryptochromes are involved in regulating circadian activity. Cryptochrome proteins have also been suggested to mediate the primary mechanism in light-dependent magnetic compass orientation in birds. Cryptochrome 1b (Cry1b) exhibits a unique carboxy terminus exclusively found in birds so far, which might be indicative for a specialised function. Cryptochrome 1a (Cry1a) is so far the only cryptochrome protein that has been localised to specific cell types within the Retina of migratory birds. Here we show that Cry1b, an alternative splice variant of Cry1a, is also expressed in the Retina of migratory birds, but it is primarily located in other cell types than Cry1a. This could suggest different functions for the two splice products. Using diagnostic bird-specific antibodies (that allow for a precise discrimination between both proteins), we show that Cry1b protein is found in the Retinae of migratory European robins (Erithacus rubecula), migratory Northern Wheatears (Oenanthe oenanthe) and pigeons (Columba livia). In all three species, Retinal Cry1b is localised in cell types which have been discussed as potentially well suited locations for magnetoreception: Cry1b is observed in the cytosol of ganglion cells, displaced ganglion cells, and in photoreceptor inner segments. The cytosolic rather than nucleic location of Cry1b in the Retina reported here speaks against a circadian clock regulatory function of Cry1b and it allows for the possible involvement of Cry1b in a radical-pair-based magnetoreception mechanism.
Petra Bolte - One of the best experts on this subject based on the ideXlab platform.
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double cone localization and seasonal expression pattern suggest a role in magnetoreception for european robin cryptochrome 4
Current Biology, 2018Co-Authors: Anja Gunther, Petra Bolte, Angelika Einwich, Emil Sjulstok, Regina Feederle, Karlwilhelm Koch, Ilia A Solovyov, Henrik MouritsenAbstract:Summary Birds seem to use a light-dependent, radical-pair-based magnetic compass. In vertebrates, cryptochromes are the only class of proteins that form radical pairs upon photo-excitation. Therefore, they are currently the only candidate proteins for light-dependent magnetoreception. Cryptochrome 4 (Cry4) is particularly interesting because it has only been found in vertebrates that use a magnetic compass. However, its structure and localization within the Retina has remained unknown. Here, we sequenced night-migratory European robin ( Erithacus rubecula ) Cry4 from the Retina and predicted the currently unresolved structure of the erCry4 protein, which suggests that erCry4 should bind Flavin. We also found that Cry1a , Cry1b , and Cry2 mRNA display robust circadian oscillation patterns, whereas Cry4 shows only a weak circadian oscillation. When we compared the relative mRNA expression levels of the cryptochromes during the spring and autumn migratory seasons relative to the non-migratory seasons in European robins and domestic chickens ( Gallus gallus ), the Cry4 mRNA expression level in European robin Retinae, but not in chicken Retinae, is significantly higher during the migratory season compared to the non-migratory seasons. Cry4 protein is specifically expressed in the outer segments of the double cones and long-wavelength single cones in European robins and chickens. A localization of Cry4 in double cones seems to be ideal for light-dependent magnetoreception. Considering all of the data presented here, especially including its localization within the European robin Retina, its likely binding of Flavin, and its increased expression during the migratory season in the migratory bird but not in chicken, Cry4 could be the magnetoreceptive protein.
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localisation of the putative magnetoreceptive protein cryptochrome 1b in the Retinae of migratory birds and homing pigeons
PLOS ONE, 2016Co-Authors: Petra Bolte, Miriam Liedvogel, Florian Bleibaum, Anja Gunther, Dominik Heyers, Anne Depping, Angelika Einwich, Lars Wohlbrand, Ralf Rabus, Ulrike JanssenbienholdAbstract:Cryptochromes are ubiquitously expressed in various animal tissues including the Retina. Some cryptochromes are involved in regulating circadian activity. Cryptochrome proteins have also been suggested to mediate the primary mechanism in light-dependent magnetic compass orientation in birds. Cryptochrome 1b (Cry1b) exhibits a unique carboxy terminus exclusively found in birds so far, which might be indicative for a specialised function. Cryptochrome 1a (Cry1a) is so far the only cryptochrome protein that has been localised to specific cell types within the Retina of migratory birds. Here we show that Cry1b, an alternative splice variant of Cry1a, is also expressed in the Retina of migratory birds, but it is primarily located in other cell types than Cry1a. This could suggest different functions for the two splice products. Using diagnostic bird-specific antibodies (that allow for a precise discrimination between both proteins), we show that Cry1b protein is found in the Retinae of migratory European robins (Erithacus rubecula), migratory Northern Wheatears (Oenanthe oenanthe) and pigeons (Columba livia). In all three species, Retinal Cry1b is localised in cell types which have been discussed as potentially well suited locations for magnetoreception: Cry1b is observed in the cytosol of ganglion cells, displaced ganglion cells, and in photoreceptor inner segments. The cytosolic rather than nucleic location of Cry1b in the Retina reported here speaks against a circadian clock regulatory function of Cry1b and it allows for the possible involvement of Cry1b in a radical-pair-based magnetoreception mechanism.
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localisation of the putative magnetoreceptive protein cryptochrome 1b in the Retinae of migratory birds and homing pigeons
PLOS ONE, 2016Co-Authors: Petra Bolte, Miriam Liedvogel, Florian Bleibaum, Anja Gunther, Dominik Heyers, Anne Depping, Angelika Einwich, Lars Wohlbrand, Ralf Rabus, Ulrike JanssenbienholdAbstract:Cryptochromes are ubiquitously expressed in various animal tissues including the Retina. Some cryptochromes are involved in regulating circadian activity. Cryptochrome proteins have also been suggested to mediate the primary mechanism in light-dependent magnetic compass orientation in birds. Cryptochrome 1b (Cry1b) exhibits a unique carboxy terminus exclusively found in birds so far, which might be indicative for a specialised function. Cryptochrome 1a (Cry1a) is so far the only cryptochrome protein that has been localised to specific cell types within the Retina of migratory birds. Here we show that Cry1b, an alternative splice variant of Cry1a, is also expressed in the Retina of migratory birds, but it is primarily located in other cell types than Cry1a. This could suggest different functions for the two splice products. Using diagnostic bird-specific antibodies (that allow for a precise discrimination between both proteins), we show that Cry1b protein is found in the Retinae of migratory European robins (Erithacus rubecula), migratory Northern Wheatears (Oenanthe oenanthe) and pigeons (Columba livia). In all three species, Retinal Cry1b is localised in cell types which have been discussed as potentially well suited locations for magnetoreception: Cry1b is observed in the cytosol of ganglion cells, displaced ganglion cells, and in photoreceptor inner segments. The cytosolic rather than nucleic location of Cry1b in the Retina reported here speaks against a circadian clock regulatory function of Cry1b and it allows for the possible involvement of Cry1b in a radical-pair-based magnetoreception mechanism.
A R Gad - One of the best experts on this subject based on the ideXlab platform.
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visual adaptability and Retinal characterization of the egyptian fruit bat rousettus aegyptiacus pteropodidae new insights into photoreceptors spatial distribution and melanosomal activity
Micron, 2020Co-Authors: Ahmed A Elmansi, M A Alkahtani, K M Alsayyad, E A Ahmed, A R GadAbstract:Our study was conducted to characterize the Retinal structure of the Egyptian fruit bat, Rousettus aegyptiacus to determine the distribution of photoreceptors and melanosomal populations in various Retinal zones. Also, we paid attention to the specific structural and functional adaptations related to their nocturnal habits. We analyzed the Retinae of 12 adult male Egyptian fruit bats using morphometrical, histological, ultrastructural, and immunoblotting standard techniques. Histological findings revealed that the Retinal cells have variations in geometrical architecture and different Retinal thickness together with their corresponding layers bearing specific choroidal papillae projecting towards the inner Retina. Immunoblotting and ultrastructure results showed that the microstructure of the Retina conforms to that pattern found in mammalian species. The Retinal photoreceptors are rod-dominant; alternatively, possess two spectral types of cones: SWS and LW/MWS cones as evidence for the basis for dichromatic vision. In addition, the outer Retina showed densely-distributed melanin granules with a significant increase in the number of pigment epithelium cells in the eccentric Retina. Furthermore, the asymmetric distribution among the Retinal quadrants for the visual pigments of both rods and cones coinciding with neuronal cells such as bipolar and ganglion cells confers instructive information about their visual perception and orientation. In conclusion, our findings indicate that R. aegyptiacus efficiently discriminates colors with complex visual adaptations to mediate increased visual acuity coopted for the nocturnal niches.
