bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complexity and scaling properties of amacrine, ganglion, horizontal, and bipolar cells in the turtle retina
Authors: Fernandez Eduardo , Eldred William D. , Ammermüller Josef , Block Arthur , Von Bloh Werner , Kolb Helga 
Published: January 2005

AbstractIn the present studies we have evaluated the complexity and scaling properties of the morphology of retinal neurons using fractal dimension as a quantitative parameter. We examined a large number of cells from Pseudemys scripta and Mauremys caspica turtles that had been labeled using Golgi‐impregnation techniques, intracellular injection of Lucifer Yellow followed by photooxidation, intracellular injection of rhodamine conjugated horseradish peroxidase, or intracellular injection of Lucifer Yellow or horseradish peroxidase alone. The fractal dimensions of two dimensional projections of the cells were calculated using a box counting method. Discriminant analysis revealed fractal dimension to be a significant classification parameter among several other parameters typically used for placing turtle retinal neurons in different cell classes. The fractal dimension of amacrine cells was significantly correlated with dendritic field diameters, while the fractal dimensions of ganglion cells did not vary with dendritic field span. There were no significant differences between the same cell types in two different turtle species, or between the same types of neurons in the same species after labeling with different techniques. The application of fractal dimension, as a quantitative measure of complexity and scaling properties and as a classification criterion of neuronal types, appears to be useful and may have wide applicability to other parts of the central nervous system. © 1994 Wiley‐Liss, Inc.
Two major types of premotoneurons in the feline trigeminal nucleus oralis as demonstrated by intracellular staining with horseradish peroxidase
Authors: Yoshida Atsushi , Yasuda Kouichi , Dostrovsky Jonathan O. , Bae Yong Chul , Takemura Motohide , Shigenaga Yoshio , Sessle Barry J. 
Published: January 2005

AbstractPrevious studies suggest that neurons in the dorsomedial subdivisions of trigeminal nucleus oralis (Vo) may contribute, to reflex control of jaw movements and to modulation of sensory information. The present study has addressed this possibility by the use of intracellular staining with horseradish peroxidase of physiologically identified neurons in Vo to examine functional and morphological properties of these neurons. Of 14 labeled neurons, eight had axon collaterals terminating exclusively in the dorsolateral subdivision of the trigeminal motor nucleus (DL neurons) and four in its ventromedial subdivision (VM neurons); axon collaterals of two neurons were not traced. Both groups of neurons sent terminal arbors into other nuclei of the lower brainstem. The DL neurons were distinguishable from the VM neurons in their receptive field (RF) location, neuronal position, somadendritic architecture, and projections to other brainstem nuclei. All neurons, except for two that were exclusively activated by noxious stimuli applied to the tongue, were responsive to light mechanical stimulation of peri‐ and intraoral structures. The RFs of the DL neurons were located in more posterior oral structures than those of the VM neurons. The RF of nearly all low‐threshold DL neurons was located in the maxillary region, and that of the VM neurons, in contrast, involved the mandibular region. The VM neurons were located medial or ventral to the DL neurons. The soma size of the VM neurons was significantly higher than that of the DL neurons. Dendritic arbors of both groups could be separated into medial and lateral components. The ratio of the dendritic transverse areas in the medial vs. later component was significantly higher in the VM neurons than in the DL neurons. The DL neurons also issued collaterals that terminated in larger brainstem areas than those of the VIM neurons. These observations provide new evidence on the morphological and functional properties of Vo neurons that contribute to reflex control of jaw and facial movements and modulation of sensory information. © 1994 Wiley‐Liss, Inc.
Ultrastructural and morphometric features of the acetylcholine innervation in adult rat parietal cortex: An electron microscopic study in serial sections
Authors: Umbriaco Denis , Watkins Kenneth C. , Descarries Laurent , Cozzari Costantino , Hartman Boyd K. 
Published: January 2005

AbstractThis study was aimed at characterizing the ultrastructural morphology of the normal acetylcholine (ACh) innervation in adult rat parietal cortex. After immunostaining with a monoclonal antibody against purified rat brain choline acetyltransferase (ChAT), more than 100 immunoreactive axonal varicosities (terminals) from each layer of the Par 1 area were photographed and examined in serial thin sections across their entire volume. These varicosities were relatively small, averaging 0.6 μm in diameter, 1.6 μM2 in surface, and 0.12 μM3 in volume. In every layer, a relatively low proportion exhibited a synaptic membrane differentiation (10% in layer I, 14% in II–III, 11% in IV, 21% in V, 14% in VI), for a I–VI average of 14%. These synaptic junctions were usually single, symmetrical (>99%), and occupied a small portion of the surface of varicosities (<3%). A majority were found on dendritic branches (76%), some on spines (24%), and none on cell bodies. On the whole, the ACh junctional varicosities were significantly larger than their nonjunctional counterparts, and both synaptic and nonsynaptic varicosities could be observed on the same fiber.A subsample of randomized single thin sections from these whole varicosities Yielded similar values for size and synaptic frequency as the result of a stereological extrapolation. Also analyzed in single sections, the microenvironment of the ChAT‐immunostained varicosities appeared markedly different from that of unlabeled varicosity profiles randomly selected from their vicinity, mainly due to a lower incidence of synaptically targeted dendritic spines. Thus, the normal ACh innervation of adult rat parietal cortex is predominantly nonjunctional (>85% of its varicosities), and the composition of the microenvironment of its varicosities suggests some randomness in their distribution at the microscopic level. It is unlikely that these ultrastructural characteristics are exclusive to the parietal region. Among other functional implications, they suggest that this system depends predominantly on volume transmission to exert its modulatory effects on cortical activity. © 1994 Wiley‐Liss, Inc.
Glomus cell differentiation in the carotid body region of chick embryos studied by neuron‐specific class III β‐tubulin isotype and leu‐7 monoclonal antibodies
Authors: Kameda Yoko , Yamatsu Yoshiyasu , Kameya Toru , Frankfurter Anthony 
Published: January 2005

AbstractDevelopment of the carotid body and the glomus cell groups in the wall of the common carotid artery and its branches was examined in chickens at various developmental stages by immunohistochemistry using three different monoclonal antibodies, i. e., anti‐neuron‐specific class III β‐tubulin isotype (TuJ1), anti‐rat brain β‐tubulin, and anti‐Leu‐7 (HNK‐1) antibodies. All the antibodies reacted with neurons. The carotid body anlage was first discerned at 6 days of incubation at the lateral portion of the third branchial artery. The cells and nerve fibers immunoreactive for TuJ1, brain β‐tubulin and Leu‐7, which were connected with the distal ganglion of the vagus nerve, were found around the carotid body anlage at this stage. Within the carotid body anlage, no immunoreactivity yet appeared. The immunoreactive cells were accumulated around the carotid body anlage until 8 days of incubation. From 9 days of incubation, the immunoreactive cells continuing with the distal vagal ganglion began to enter into the carotid body anlage and also dispersed widely along the common carotid artery and its branches, giving rise to the glomus cells. At 12 days of incubation, a large portion of the carotid body was occupied by the immunoreactive cells. Thus, the present study evidences that the glomus cells in the carotid body and around the arteries are emigrés that arrive in each residential place from the distal vagal ganglion. Immunoreactivity for TuJ1, brain β‐tubulin, and Leu‐7 in the glomus cells started to decrease at late stages of embryonic development. After hatching, no TuJ1‐immunoreactive cells were detected in the carotid body region. © 1994 Wiley‐Liss, Inc.
Electron microscopic study on the development of the carotid body and glomus cell groups distributed in the wall of the common carotid artery and its branches in the chicken
Authors: Kameda Yoko 
Published: January 2005

AbstractDevelopment of the carotid body and the glomus cell groups in the wall of the common carotid artery and its branches was studied in chickens at various developmental stages by electron microscopy. At 8 days of incubation, the carotid body anlage consisted of mesenchyme‐like cells, whereas the clusters of epithelial cells, which occasionally contained a few dense‐cored vesicles and were accompanied by unmyelinated nerve fibers, were located in the region surrounding the carotid body anlage and in the wall of the common carotid artery. Subsequently, the granule‐containing cells together with nerve fibers were detected in the periphery of the carotid body anlage. At 12 days of incubation, a large number of granule‐containing cells (glomus cells) were dispersed throughout the carotid body parenchyma and were also widely distributed along the common carotid artery and its branches. The cells frequently extended long cytoplasmic processes that made contact with other glomus cells and nerve fibers. Synaptic junctions which showed desmosome‐like thickening of pre‐ and postsynaptic membranes and accumulations of small clear vesicles (around 50 nm in diameter) were first detected along the contact between the long axons and glomus cells at 12 days of incubation. In the wall of the common carotid artery, interdigitations between the cytoplasmic processes of glomus cells and smooth muscle cells began to form. Sustentacular cells investing partly the glomus cells were also discerned both in the carotid body and around the arteries at this stage. At 14 days of incubation, the glomus cells expressed most of the characteristics of the mature cells, and the synaptic junctions displaying afferent morphology appeared; the secretory granules of glomus cells were accumulated near and attached to the desmosome‐like thickening of apposed membranes. © 1994 Wiley‐Liss, Inc.
Localization and developmental expression of the NMDA receptor subunit NR2A in the mammalian retina
Authors: Hartveit E. , Brandstätter J. H. , Sassoè‐Pognetto M. , Laurie D. J. , Seeburg P. H. , Wässle H. 
Published: January 2005

AbstractThe localization of the N‐methyl‐D‐aspartate receptor subunit NR2A was studied, by using light microscopic immunocytochemistry, in the retina of adult rat, rabbit, cat, and monkey. Strong, punctate immunolabeling was observed in the inner plexiform layer indicating a synaptic localization of the NR2A subunit. The punctate labeling was concentrated in two bands corresponding to the on‐ and off‐sublaminae of the inner plexiform layer.The punctate character of immunofluorescence suggested a synaptic localization of the receptor. This was confirmed by electron microscopy of immunostained adult rat retina. The staining was localized postsynaptic to cone bipolar cells, and only one of the two postsynaptic elements of the dyad was labeled. Staining was not observed at extrasynaptic plasma membranes.In situ hybridization of adult rat retina showed expression of the NR2A subunit in virtually all ganglion cells and displaced amacrine cells in the ganglion cell layer and in a subset of amacrine cells in the inner nuclear layer.The postnatal developmental expression of the NR2A subunit was studied in rat retina by light microscopic immunocytochemistry. Punctate immunolabeling appeared prior to eye opening, and the developmental profile of NR2A could be compatible with a role in development of circuitry in the inner plexiform layer. © 1994 Wiley‐Liss, Inc.
Restricted expression of a new paired‐class homeobox gene in normal and regenerating adult goldfish retina
Authors: Levine Edward M. , Hitchcock Peter F. , Glasgow Eric , Schechter Nisson 
Published: January 2005

AbstractWe describe the cloning and expression pattern of a new paired‐class homeobox gene, Vsx‐1, in the continuously growing retina of the goldfish. Vsx‐1 belongs to a subset of paired‐class homeobox genes that lack a second DNA binding domain, the paired‐domain, and is closely related to the C. elegans ceh‐10 gene. In the adult goldfish, Vsx‐1 expression is restricted to the neural retina. In the central, mature retina, Vsx‐1 mRNA is synthesized in a subset of differentiated cells in the inner nuclear layer in a pattern suggestive of bipolar cells. In immature retina, adjacent to the retinal margin, Vsx‐1 is expressed in a relatively broader subset of newly postmitotic cells but is downregulated in some of these cells to form the mature expression pattern. Following retinal injury, during the early phase of regeneration, Vsx‐1 mRNA synthesis appears tp be upregulated in cells in the inner nuclear layer and is expressed de novo in cells outside this layer. By virtue of its identity as a transcriptional regulatory gene and its patterns of expression, we speculate that Vsx‐1 may stabilize the differentiated state of a subset of cells in the inner nuclear layer and may be involved in cellular differentiation during retinal development and regeneration. © 1994 Wiley‐Liss, Inc.
Immunocytochemical localization of the α7 subunit of the nicotinic acetylcholine receptor in the rat central nervous system
Authors: del Toro Eduardo Dominguez , Juiz Jose M. , Peng Xiao , Lindstrom Jon , Criado Manuel 
Published: January 2005

AbstractPrevious molecular cloning studies have revealed that α‐bungarotoxin binding proteins present in the brain are members of the neuronal nicotinic acetylcholine receptor gene family. The α7 subunit is structurally related to the agonist binding subunits present in the central and peripheral nervous systems and, when expressed in Xenopus oocytes, forms functional channels blockable by α‐bungarotoxin. In the present study, three different monoclonal antibodies raised against the α7 subunit were used to map its distribution throughout the central nervous system of the rat.Immunohistochemical localization revealed that the α7 subunit is expressed in most regions of the brain, being, overall, well correlated with previous “in situ” localization of α7 transcripts and α‐bungarotoxin autoradiographic binding studies. Particularly strong immuno‐reactivity was observed in several sensory and motor nuclei of the brainstem as well as the red nucleus. At the cellular level, α7 immunostaining was usually found both in somata and dendrites, whereas axonal and terminal labeling was not observed.The widespread distribution of the α7 subunit polypeptide is consistent with immunoprecipitation data demonstrating that it is a component of the predominant subtype of brain α‐bungarotoxin‐sensitive nicotinic receptors. © 1994 Wiley‐Liss, Inc.
Morphology of retinal axon arbors induced to arborize in a novel target, the medial geniculate nucleus. II. Comparison with axons from the inferior colliculus
Authors: Pallas S. L. , Sur M. 
Published: January 2005

AbstractSpecific neonatal lesions in ferrets can induce retinal axons to project into the medial geniculate nucleus (MGN). In the accompanying paper (Pallas et al., this issue), we described the morphology of these retinal ganglion cell axons. Those results and others (Roe et al. [1993] J. Comp. Neurol. 334:263) suggest that these axons belong to the W class of retinal axons.In this paper, the retino‐MGN axons are compared with the normal inputs to the MGN from the brachium of the inferior colliculus (BIC). We first sought to determine further the extent to which a novel target might influence retinal axon arbor morphology. The second issue concerns retinal topography. Ferrets with retinal projections to the MGN have a two‐dimensional retinotopic map in the MGN and the primary auditory cortex rather than the one‐dimensional tonotopic map normally present (Roe et al. [1990] Science 250:818). To investigate whether there might be an anatomical substrate for a two‐dimensional retinotopic map in the MGN, we compared the space‐filling characteristics of the retino‐MGN axons with the IC‐MGN axons.Our results show that the branched retino‐MGN axons resemble normal retinal W axons much more closely than they resemble the normal inputs to MGN. In addition, most of the axon arbors from the BIC are elongated along the rostrocaudal (isofrequency) axis, whereas the branched retino‐MGN axons are more spatially restricted, suggesting an anatomical substrate for a retinotopic map in the MGN of the rewired ferrets. © 1994 Wiley‐Liss, Inc.
Cytoarchitecture and responsiveness of the medial ansate region of the cat primary somatosensory cortex
Authors: Myasnikov Alexandre A. , Dykes Robert W. , Avendano Carlos 
Published: January 2005

AbstractTo understand its relationship to somatosensory areas in other species, we studied the rostral bank of the medial ansate sulcus in adult cats. Neurons in the shoulder and upper part of the sulcal wall responded to low‐threshold cutaneous stimuli much like neurons on the crown of the gyrus, whereas neurons in some deeper portions of the sulcus required more intense but innocuous somatic stimuli. Because we found much of the body surface re‐represented in this area, we suggest that, besides the representation in area 3b, there is another cutaneous representation of the hindlimb and trunk located on the gyral crown near the medial end of the medial ansate sulcus and of the forelimb and trunk within the medial ansate sulcus. Posterior to this second cutaneous representation, many parts of the body were also represented in regions activated by more intense stimuli and having a different cytoarchitecture, suggesting that they were part of another body representation.Area 3b and the shoulder of the gyrus were distinguished by relatively intense acetylcholinesterase staining of layers III and IV. In the wall of the sulcus, all layers except layer I were uniformly stained to a point where electrophysiological recordings showed the cortex to be unresponsive, whereupon the outer two‐thirds of layer I became very pale. Neurons activated by afferents from knee joints were found only in a small area; we did not find a mediolateral band serving joint afferents as is reported in primates. These data suggest that cat somatosensory cortex differs in some ways from primates but that it contains multiple representations of the body, as do most other mammals. © 1994 Wiley‐Liss, Inc.
Metabotropic glutamate receptor mGluR1 distribution and ultrastructural localization in hypothalamus
Authors: van den Pol Anthony N. 
Published: January 2005

AbstractThe metabotropic glutamate receptor mGluR1 is a G‐protein‐coupled glutamate receptor whose activation induces phosphotidylinositol hydrolysis and increases diacylglycerol and cytoplasmic calcium. By using affinity‐purified antisera against a partial amino acid sequence of mGluR1α, deduced from the nucleotide sequence of the cloned gene, the heterogeneous expression of this glutamate receptor was studied immunocytochemically with light and electron microscopy in the rat hypothalamus. Immunoreactivity was restricted to cell bodies and dendrites throughout many regions of the adult hypothalamus, including the preoptic area, anterior hypothalamus, suprachiasmatic nucleus, dorsomedial hypothalamus, and periventricular region. Strong immunolabeling was found in the lateral hypothalamus where immunoreactivity could be detected as early as embryonic day 18. Intense immunoreactivity was also found in the medial mammillary nuclei. In contrast to the strong labeling in many other regions, the neuroendocrine neurons of the arcuate, supraoptic, and paraventricular nuclei showed relatively little staining in adults.With light microscopy, immunoperoxidase labeling was found distributed in patches on the cytoplasmic side of the plasma membrane of immunoreactive neurons. When the same tissue was examined ultrastructurally, the patches were not restricted to synaptic specializations but were also found distributed on perikaryal and dendritic membranes sometimes associated with synapses and sometimes not. Some immunoreactive membranes showed no immunolabeling at the synaptic junction. When the tissue was strongly stained, labeling could be found in the cytoplasm of immunoreactive cells. No immunostaining was found on axons or presynaptic boutons.Together with other evidence showing a widespread expression of many different subtypes of both ionotropic and metabotropic receptors, these data support the hypothesis that glutamate may regulate hypothalamic cellular activity with a number of physiologycally different mechanisms, and these mechanisms include second‐messenger systems activated by G proteins. © 1994 Wiley‐Liss, Inc.
Fine structure of rat septohippocampal neurons. III. Recovery of choline acetyltransferase immunoreactivity after fimbria‐fornix transection
Authors: Naumann T. , Kermer P. , Frotscher Michael 
Published: January 2005

AbstractMost cholinergic projection neurons in the medial septal nucleus (MS) lose their capability to synthesize choline acetyltransferase (ChAT) after axotomy by bilateral fimbria‐fornix transection. We have recently shown that identified septohippocampal neurons survive axotomy up to 10 weeks and display fine‐structural characteristics of cells in control rats. However, the fate and functional role of these neurons remained unclear. Here we describe observations made in rats which survived axotomy for 6 months.Adult Sprague‐Dawley rats were subjected to bilateral transection of the fimbria‐fornix system. In some animals septochippocampal projection neurons were labeled by the retrograde fluorescent tracer Fluoro‐Gold (FG) prior to axotomy. After varying survival times following fimbria‐fornix transection, the animals were fixed and sections of the septal region immunostained for ChAT.Three weeks postlesion, the number of ChAT‐positive cells in the MS was reduced to 19% of control, suggesting a severe neuronal loss. However, 10 weeks and 6 months after axotomy this value increased to 28% and 54%, respectively. Fine‐structural analysis of ChAT‐postive neurons after 6 months survial revealed all characteristics of vital cells including normal input synapses. The majority of these cells could be identified as former septohippocampal projection neurons by the presence of FG.We conclude that many neurons in the MS have the capacity to restore their transmitter synthesis in a long‐lasting process following axotomy. © Wiley‐Liss, Inc.