bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monoclonal antibody rat 401 recognizes schwann cells in mature and developing peripheral nerve
Authors: Friedman Beth , Zaremba Sam , Hockfield Susan 
Published: January 2005

AbstractMonoclonal antibody Rat 401 recognizes subsets of cells in the developing central and peripheral nervous systems. Previous studies have shown that in the central nervous system (CNS) Rat 401 immunoreactivity diminishes sharply with cellular differentiation. Here we have examined the time course, cellular localization, and biochemical nature of the Rat 401 antigen in the rat peripheral nerve. In contrast to the CNS, in the periphery Rat 401 immunoreactivity is maintained into adulthood. Rat 401 staining is restricted to Schwann cells in mature peripheral nerve. Myelin‐related Schwann cells are intensely immunoreactive, whereas nonmyelin‐related Schwann cells are weakly immunoreactive. Unlike many Schwann cell markers, Rat 401 staining is maintained in cultured Schwann cells that lack axon contact. Biochemical analyses show that the antigen recognized by Rat 401 in the peripheral nerve is identical to that in embryonic CNS. The results demonstrate that the capacity for maintained Rat 401 immunoreactivity is restricted to Schwann cells as these cells are stained in adult animals as well as in embryos. In contrast, the same antigens are lost from the CNS at an early stage of development.
Cytoskeletal components of the adherens junctions between the photoreceptors and the supportive müller cells
Authors: Williams David S. , Arikawa Kentaro , Paallysaho Taru 
Published: January 2005

AbstractThe outer limiting “membrane” (OLM) of the vertebrate retina comprises a series of heterotypic adherens junctions between the photoreceptors and the supportive Müller cells. These junctions appear to support the photoreceptors, which in teleosts, anurans, and birds are motile, and thus help them maintain their orientation with respect to incoming light. In an unusual role for this type of junction, they also provide a semipermeable barrier, preventing the diffusion of some proteins out of the extracellular space that surrounds the inner and outer segments of the photoreceptors. Using immunoelectron microscopy, we examined the association of actin, myosin, alpha‐actinin, and vinculin with the OLM junctions of the adult chicken retina. Vinculin was detected close to the plasma membrane in the cytoplasmic plaques of the junctions, as it was in the adherens junctions of the retinal epithelium. Labelling of actin, myosin, and alpha‐actinin was spread more throughout the plaques and was distributed unevenly about the junctions; labelling was much more extensive in the Müller cells than in the photoreceptors. Thus, the junctions of the OLM show similarity to the other adherens junctions in that their cytoplasmic plaques contain actin, myosin, alpha‐actinin, and vinculin. But the large aggregation of actin, myosin, and alpha‐actinin in the Müller cells, and their resulting asymmetrical distribution about the junctions, is unusual, and possibly an adaptation for the special function of the OLM junctions, in providing both structural support for the motile photoreceptors and a semipermeable barrier.
Axonal regrowth in the amyelinated optic nerve of the myelin‐deficient rat: Ultrastructural observations and effects of ganglioside administration
Authors: Marciano F. F. , Gocht A. , Dentinger M. P. , Hof L. , Csiza C. K. , Barron K. D. 
Published: January 2005

AbstractIt has been postulated that myelin degradation products may inhibit regrowth of mammalian central axons and that central nervous system (CNS) myelin and oligodendrocytes may constitute a “nonpermissive substrate” for axonal growth. To address these issues, we utilized an X‐linked rat mutant, myelin‐deficient or md. In the optic nerve of this mutant, 40 days and more postnally, normal myelin is absent and oligodendrocytes are few (Dentinger et al. Brain Res. 344:255–266, 1985). Twenty‐eight days before sacrifice, we operated on four groups of 50‐day‐old md rats and age‐matched normal littermates according to the following protocols: (1) unilateral intraorbital optic nerve crush; (2) beginning within 1 hour of nerve crush, daily intraperitoneal injection of GM1 ganglioside (20 mg/kg) dissolved in phosphate‐buffered saline (PBS); (3) daily intraperitoneal injection of PBS alone, also begun within 1 hour of nerve crush; (4) severance of the optic nerve immediately behind the papilla 16 or 21 days after the primary crush lesions. Additionally, normal and md rats were killed 4 and 14 days after unilateral optic nerve injury. Nerves of unoperated md rats and their normal littermates were also processed. In the operated animals that did not receive GM1, ultrastructural analysis 4, 14, and 28 days after lesioning revealed that md optic nerves contained significantly greater numbers of regenerating axons, including growth cones and varicosities, than nerves of normal rats. Notably, 28 days postoperatively, (group 1), regenerating axons were still abundant in md nerve, whereas, in nerves of normally myelinated littermates, axonal numbers were diminished markedly. Regenerating optic axons of both md and normally myelinated rats were oriented by linear astrocytic arrays and often were enclosed by astrocytic cytoplasm. In normal litternates, GM1 administration (group 2) induced a significant increase in the number of axons within the operative lesion. Paradoxically, GM1 inhibited the ordinarily robust regeneration of md axons. PBS‐injected md and normal rats (group 3) showed no significant differences from noninjected, operated animals. Severance of the nerve at the papilla (group 4) 7–12 days before sacrifice confirmed the origination of axonal regrowth by retinal ganglion cells. The data provide in vivo support for a role of myelin breakdown products or the secretory products of oligodendroglia in the inhibition of regenerative axonal sprouting within mammalian CNS.
Synaptology of luteinizing hormone‐releasing hormone (LHRH)‐immunoreactive cells in the nervus terminalis of the gray short‐tailed opossum (monodelphis domestica)
Authors: Zheng Li‐Mou , Pfaff Donald W. , Schwanzel‐Fukuda Marlene 
Published: January 2005

AbstractLight and electron microscopic immunocytochemistry were used to examine the structure of LHRH neurons and fibers in the nervus terminalis of the gray short‐tailed opossum (Monodelphis domestica).LHRH‐immunoreactive neurons and fibers form a loose plexus within the fascicular network of the ganglion terminale on the median surface of the olfactory bulb. There are at least two populations of LHRH‐immunoreactive neurons within the network of the ganglion terminale: fusiform and round neurons similar to those described in the forebrain. At the ultrastructural level, axosomatic and axodendritic contacts were seen between LHRH‐immunoreactive and nonimmunoreactive elements in the ganglion terminale. These contacts were classified as (1) synaptic input, with asymmetric synapses seen between a nonimmunoreactive axon terminal and a LHRH‐immunoreactive cell body or a nonimmunoreactive axon terminal and a LHRH‐immunoreactive dendritic process. (2) synaptic output, with symmetric synapses seen between LHRH‐immunoreactive and nonimmunoreactive processes.This study is the first systematic examination of the ultrastructure of the LHRH‐immunoreactive neurons and their synaptic contacts in the nervus terminalis. The possible integrative roles for this LHRH‐immunoreactive system are discussed.
Synaptic connections of rod bipolar cells in the inner plexiform layer of the rabbit retina
Authors: Strettoi Enrica , Dacheux Ramon F. , Raviola Elio 
Published: January 2005

AbstractWe have reconstructed from electron micrographs of a continuous series of thin sections the synaptic connections of the axonal arborizations of all the rod bipolar cells contained in a small region of the retina of the rabbit.We observed that all rod bipolars share the same pattern of connectivity and are probably functionally equivalent. As a rule, they do not contact ganglion cells. Their prevalent synaptic output is on narrow‐field, bistratified, and indoleamine‐accumulating amacrine cells. Their dominant inputs are the reciprocal synapses from the indoleamine‐accumulating amacrines, but they also receive a sizable number of synaptic contacts from other, non‐reciprocal, amacrine cells. The lateral spread of scotopic signals at the synapse between rod bipolars and narrow‐field, bistratified amacrines is small. Finally, in the rabbit, as in the cat, a narrow‐field, bistratified amacrine is inserted in series along the rod pathway.
Alpha2‐adrenergic binding sites in the medulla oblongata of tree shrews demonstrated by in vitro autoradiography: Species related differences in comparison to the rat
Authors: Flügge G. , Jurdzinski A. , Brandt S. , Fuchs E. 
Published: January 2005

AbstractAlpha2‐adrenergic binding sites in the medulla oblongata of tree shrews and rats were detected and quantified by in vitro‐autoradiography with the α2‐antagonist 3H‐rauwolscine (3H‐RAUW).The autoradiographic pattern of the radioligand binding in the tree shrew medulla oblongata resembles that which has been described by others for the human myelencephalon. This pattern coincides well with the occurrence of catecholaminergic structures detected by immunocytochemistry with antibodies against phenylethanolamine‐N‐methyltransferase and tyrosine hydroxylase. In contrast to the rat, where only the nucleus tractus solitarii and the nucleus dorsalis nervi vagi were labeled, five discrete nuclei specifically bound 3H‐RAUW in tree shrews. The highest number of binding sites was detected in the nucleus dorsalis nervi vagi (nX; Bmax: 333 fmoles/mg) and the nucleus tractus solitarii (NTS; 311 fmoles/mg), followed by the nucleus nervi hypoglossi nXII; 297 fmoles/mg), the nucleus reticularis parvocellularis (FRS; 230 fmoles/mg), and the area of the catecholamine cell groups A1 and C1 (area C1; 202 fmoles/mg). Maximal binding in the two labeled nuclei of the rat was 158 fmoles/mg. The discrete nuclei of the two species also showed different affinities for 3H‐RAUW with Kd ranging from 0.17 to 0.83 nM in tree shrews and 1.80 to 1.95 nM in rats.Competition experiments revealed that the radioligand bound specifically to α2‐binding sites. In the tree shrew, nX, nXII and the area C1, also have a relatively high affinity for the α1‐antagonist prazosin which is a quality of the adrenoceptor subtype α2B. Furthermore, in the area C1, 3H‐RAUW binding was inhibited by the dopamine antagonist haloperidol.There are thus species related as well as regional differences with respect to the number, the affinity, and the pharmacological properties of α2‐binding sites in the medulla oblongata. In tree shrews, α2‐adrenoceptors can be autoradiographically quantified in regions which are not labeled in the rat, although former data predicted the existence of such receptors, e.g., in the area of the adrenaline cell group C1.
Light and electron microscopical studies on the spherical neurons in the electrosensory lateral line lobe of the gymnotiform fish, Sternopygus
Authors: Losier Bruno J. , Matsubara Joanne A. 
Published: January 2005

AbstractSpherical cells are a principal cell type of the electrosensory lateral line lobe (ELLL) and play a crucial role in the jamming avoidance response (JAR) behavior. Since Sternopygus, a low frequency gymnotiform genus, does not display a JAR we searched for spherical cells in its ELLL. While present in Sternopygus, spherical cells differed remarkedly from those in the high‐frequency gymnotiforms, Eigenmannia and Apteronotus. This study reveals species‐characteristic differences in the morphology and synaptology of the spherical cell, a projection neuron located in the deep neuropil layer (DNL) of the ELLL. In contrast to the adendritic spherical cell of other species, the spherical neuron in Sternopygus exhibits an extensive basilar dendrite that extends into the primary electroreceptive afferent zone, the deep fiber layer (DFL). In Sternopygus, these neurons are distributed evenly across the full length of each tuberous subdivision, with cell densities highest in the centrolateral subdivision. At the ultrastructural level, the contacts on the soma, proximal, and distal dendrite of the spherical neuron in Sternopygus are asymmetrical chemical synapses, quite distinct from the electrotonic gap junctions found on the spherical neurons of other species.
Organization of projections from olfactory epithelium to olfactory bulb in the frog, Rana pipiens
Authors: Duncan H. J. , Nickell W. T. , Shipley M. T. , Gesteland R. C. 
Published: January 2005

AbstractOne hypothesis for the coding of olfactory quality is that regions of the olfactory epithelium are differentially sensitive to particular odor qualities and that this regional sensitivity is conveyed to the olfactory bulb in a topographic manner by the olfactory nerve. A corollary to this hypothesis is that there is a sufficiently orderly connection between the epithelium and the olfactory bulb to convey this topographical coding. Thus we examined topography in the projection from epithelium to bulb in the frog, which has been the subject of numerous electrophysiological studies but has not yet been examined using modern neuroanatomical techniques.The tracer WGA‐HRP was applied to the ventral or to the dorsal olfactory epithelium, or both. Anterograde transport of label to the olfactory bulb was seen after as few as 2 days; label was still present in the bulb as long as 21 days postinjection. In cases where WGA‐HRP was applied to the entire epithelium, there was dense anterograde labelling of the ipsilateral olfactory bulb. In addition, a small medial portion of the contralateral bulb was labelled.Injections limited to either the ventral or dorsal epithelium produced patterns of anterograde labelling in the glomerular layer of the olfactory bulb, which varied with the size and location of the injection. With very large injections in either the dorsal or ventral epithelium, label appeared to be evenly distributed in the glomerular layer. With smaller injections in the ventral epithelium, there was heavier labelling in the lateral than in the medial portions of the glomerular layer, although light labelling was found in all regions of the glomerular layer. In contrast, injection sites restricted to the dorsal epithelium produced more anterograde labelling in the medial than lateral portions of the glomerular layer. These patterns extended throughout the dorsal‐ventral extent of the bulb.Within the limits of the anterograde tracing technique used, we were unable to detect any systematic relationship between the pattern of labelling in the glomerular layer and the medial‐lateral or rostral‐caudal location of the injection site in either the ventral or dorsal epithelium.We conclude that in the frog, as in other amphibia, there is only a limited degree of topographic order between the epithelium and the olfactory bulb.
Substance P and enkephalins in the superficial layers of the rat superior colliculus: Differential plastic effects of retinal deafferentation
Authors: Miguel‐Hidalgo Jose Javier , Senba Emiko , Takatsuji Koichi , Tohyama Masaya 
Published: January 2005

AbstractIn this work we studied the effects of unilateral eye enucleation on the contents and distribution of leu‐enkephalin‐, met‐enkephalin‐arg6‐gly7‐leu8‐, and substance‐P‐like immunoreactivities (L‐ENK‐I, ENK‐8‐I, and SP‐I, respectively) in the superficial layers of the rat superior colliculus (SC) by means of the unlabelled antibody peroxidase‐antiperoxidase method. In the normal rat only a few L‐ENK‐I neurons appear dispersed in the stratum griseum superficiale. No immunostained somata appear in the stratum opticum. The most striking effect of unilateral enucleation was the dramatic appearance of a laminarly distributed population of L‐ENK‐I and/or ENK‐8‐I neurons in the dorsal stratum opticum of the SC contralateral to the enucleated side. This population of immunoreactive cells was observed with all the survival times examined in the present study (3, 7, 15, and 30 days) and was always accompanied by an increase in the immunostaining of L‐ENK‐I and/or ENK‐8‐I fibers in the contralateral stratum griseum superficiale. Enucleation also produced a decrease in the immunostaining of SP‐I dendrites that only became obvious 15 days after enucleation. However, the number of SP‐I somata or terminal‐like immunoreactive structures showed no detectable changes.These results show that retinal deafferentation of the superficial layers of the rat SC has different effects on some immunohistochemically distinguishable neuronal subgroups in the SC, suggesting different functional or trophic relationships of the retinal input to these groups of neurons.
Neonatal infraorbital nerve transection in the rat: Comparison of effects on substance P immunoreactive primary afferents and those recognized by the lectin Bandierea simplicifolia‐I
Authors: White Fletcher A. , Bennett‐Clarke Carol A. , Macdonald Gordon J. , Enfiejian Howard L. , Chiaia Nicolas L. , Rhoades Robert W. 
Published: January 2005

AbstractRetrograde tracing, immunocytochemical, and histochemical methods were used to determine the manner in which different classes of trigeminal (V) ganglion cells respond to transection of their axons during infancy. Retrograde tracing with true blue (TB), histochemistry using the plant lectin Bandieraea simplicifolia‐I (BS‐I), and immunocytochemistry using an antiserum directed against substance P (SP) were carried out in the V ganglion and V brainstem complex of normal adult rats. In the adult V ganglion, 11.9 ± 1.9% of the cells that sent axons into the infraorbital nerve (ION) contained SP‐like immunoreactivity (SPLI) and 26.9 ± 3.6% bound the lectin BS‐I. Only 2.7 ± 1.6% of ION cells were labelled by both the SP antiserum and BS‐I. Transection of the ION on the day of birth had very different effects upon primary afferent neurons containing SPLI and those labelled by BS‐I. We have previously shown that such lesions result in a significant expansion of the portion of SpC innervated by primary afferents containing SPLI and we have also provided data consistent with the proposal that ganglion cells recognized by an antiserum directed against SP are more likely than other primary afferent neurons to survive neonatal axotomy. In the present study, combination of retrograde tracing with TB and lectin binding histochemistry showed that cells recognized by BS‐I were selectively lost after neonatal ION transection. Only 14.2 ± 4.4% of the ION ganglion cells that projected into this nerve at the time of the lesion and that survived neonatal axotomy were BS‐I positive when the animals reached adulthood. Neonatal ION transection also resulted in a permanent reduction in the density of BS‐I binding in SpC. Bandieraea simplicifolia‐I binding in the brainstem ipsilateral to the damaged nerve was almost completely gone within 1 day of the nerve transection and recovered only partially by the time the rats were 2 months of age. In alternate sections tested with the SP antiserum, there was a slight reduction in the density of SPLI in the deafferented SpC on postnatal days 4 and 5, but this change never approached that observed for BS‐I binding.
NADPH‐diaphorase reactive neurons of the rabbit retina: Differential sensitivity to excitotoxins and unusual morphologic features
Authors: Sagar Stephen M. 
Published: January 2005

AbstractVarious populations of retinal and brain neurons display different degrees of sensitivity to the toxic effects of excitatory amino acid agonists. To further define this phenomenon, the effects of intravitreal injections of kainic acid, N‐methyl‐D‐aspartate (NMDA), quinolinic acid, and ibotenic acid on NADPH‐diaphorase (NADPHd) reactive cells of the rabbit retina were examined. In normal rabbit retinas, NADPHd histochemistry selectively stains two populations of cells at the inner margin of the inner plexiform layer: large densely staining (Type I) and more numerous, smaller and lightly staining (Type II) cells. All of the toxins studied destroy both cell types at high doses. Kainic acid, however, at low doses destroys Type I cells but selectively spares Type II cells. NMDA injections result in a more complex and less consistent pattern of cell loss; overall, the Type I cells are perhaps slightly resistant to this agent as compared to Type II cells. The Type I neurons in this respect are analogous to striatal NADPHd‐reactive neurons, which have, at most, a slight relative resistance to NMDA neurotoxicity.The excitotoxin lesions reduce the complexity of the fiber plexus in the inner plexiform layer and thereby reveal anatomic features of surviving NADPHd reactive neurons that are not apparent in normal retinas. In particular, each Type I cell gives off several fine, straight, beaded processes that emanate from dendrites and run several millimeters in the inner plexiform layer. These processes are presumably involved in long‐distance interactions within the retina. Excitotoxin lesions may provide a generally useful anatomic tool for elucidating morphological features of neurons stained by histochemical and immunohistochemical methods.
On variables that affect estimates of the true sizes and densities of radioactively labeled cell nuclei
Authors: Clark S. J. , Cynx J. , Alvarez‐Buylla A. , O'Loughlin B. , Nottebohm F. 
Published: January 2005

AbstractTritiated thymidine has been widely used as a nuclear marker of cell birth. The true diameters and packing densities (nuclei/μm3) of such radioactively labeled nuclei cannot be measured directly from tissue sections. Here we show that existing stereological corrections cannot be applied to data from radioactively labeled nuclei. We empirically measured the number of silver grains exposed by nuclei containing tritiated thymidine. The nuclei were separated from the photographic emulsion by known thicknesses of fixed, embedded avian telencephalon. The results of this experiment were used to develop an equation that estimates the number of silver grains exposed by a cell nucleus of any given diameter, containing a given amount of radioactive label, and located at any given distance from the photographic emulsion. The equation also allows one to calculate the probability that a label‐containing nucleus will be correctly classified as labeled. Simulations of the equation revealed that not all label‐containing nuclei are correctly classified by using commonly employed identification procedures and that larger nuclei are less likely to be correctly classified than smaller nuclei, given the same amount of label. The equation can be used to modify one class of existing sterological equations so as to be applicable to measurements of radioactively labeled nuclei. Finally, we discuss the assumptions and limitations of this modification.