bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential response of neutral endopeptidase 24.11 (“enkephalinase”), and cholinergic and opioidergic markers to hypoglossal axotomy
Authors: Back Stephen A. , Gorenstein Charles 
Published: January 2005

AbstractNeutral endopeptidase 24.11 (NEP; “enkephalinase”) may inactivate a number of centrally active neuropeptides including the enkephalins and substance P. In most areas of the central nervous system, the cell types which express NEP activity are not known. The hypoglossal nucleus (N. XII) was selected as a model system to characterize the cytochemical localization of NEP. The effect of hypoglossal nerve axotomy upon the distribution of NEP activity in the hypoglossal nucleus was compared to the effect upon cholinergic markers, the muopiate receptor, and the enkephalins.By use of a fluorescence histochemical method, NEP was localized at all levels of N.XII to
the soma and proximal processes of the majority of the apparent motor neurons in the nucleus.
Fluorescent double‐labeling studies revealed the presence of numerous enkephalinergic
varicosities which localized to the neuropil surrounding NEP‐stained motor neurons. To
determine whether NEP was synthesized by these motor neurons, 18 rats received a unilateral
transection of the hypoglossal nerve. A pronounced decrease in NEP staining in N.XII was
observed on the operated side as early as 3 days following axotomy. This decrease persisted at all
levels of the nucleus for about 5 weeks. By 7 weeks, the staining between the control and
operated sides was indistinguishable. By contrast, there was no apparent change in the density
or distribution of enkephalin‐immunoreactive varicosities in five animals examined 6 to 32 days
following axotomy. Radioligand binding of [3H]DAMGO to the μ‐opiate receptor in N.XII was
studied in 20 animals by quantitative autoradiography at 2, 6, and 11 days after axotomy. No
significant changes in the level of radioligand binding to the μ‐receptor were detected in
response to axotomy. In contrast to the opiate system, the cholinergic enzymes choline
acetyltransferase, acetylcholinesterase, and pseudocholinesterase showed a coordinate decrease
in motor neuron‐associated staining on the operated side of N.XII at 3 ,6 , and 11 days following
axotomy which paralleled the decrease in NEP staining. By contrast, the lysosomal enzyme
marker, acid phosphatase, showed a pronounced increase in staining on the operated side.The results of this study are consistent with the synthesis of NEP by cholinergic N.XII motor neurons and indicates that the enkephalins and NEP in N.XII are closely associated, but derive from separate neuronal populations. The widespread overlap in the distribution of NEP‐stained motor neurons and enkephalinergic varicosities in N.XII provides additional anatomical support for a potential role for NEP in the inactivation of centrally active enkephalins. The apparently stable levels of the enkephalins and μ‐opiate receptor after axotomy, in contrast to the coordinate decrease in cholinergic enzyme staining, suggest a differential regulation of the opiate and cholinergic systems in response to axotomy. © 1994 Wiley‐Liss, Inc.
Central terminations of low‐threshold mechanoreceptive afferents in the trigeminal nuclei interpolaris and caudalis of the cat
Authors: Miyoshi Y. , Suemune Setsuko , Yoshida Atsushi , Takemura Motohide , Nagase Yoshitaka , Shigenaga Yoshio 
Published: January 2005

AbstractPrevious studies indicate that vibrissa, nonvibrissa, guard hair, hairy skin, and periodontal ligament afferents give rise to morphologically distinct terminal arbors in the trigeminal nuclei principalis (Vp) and oralis (Vo) in the cat. The present study describes the extent to which morphological and functional relationships exist in the nuclei interpolaris (Vi) and caudalis (Vc). Twenty‐two fibers were physiologically characterized and stained by intra‐axonal HRP injection techniques. The fast adapting (FA) vibrissa (VF) afferents gave rise to compact and circumscribed arbors in Vj and Vc. These tended to be larger in Vc than in Vi. The slowly adapting (SA) vibrissa (VS) afferents in Vi and Vc had more widespread and larger arbors than those of the VF afferents. The VS arbors in Vc tended to be larger and less circular than those in Vi. Guard hair (GH) afferents gave rise to circumscribed arbors in both nuclei, but those in Vc tended to have larger and more circular arbors than those in Vi. Down hair (DH) afferents gave rise to small, circumscribed arbors or a few distinct patches of boutons within a small area in Vi; arbors in Vc were less extensive and “stringy.” Unlike other afferents, DH arbors were larger in Vi than in Vc, but smaller than those of GH afferents in either nuclei. The SA hairy skin (SS) afferents had arbors that were widespread with a few distinct patches of boutons; the arbors in Vc were larger than those in Vi. The arbors of SS afferents were smaller than those of VS and GH afferents in both nuclei. Like GH afferents, FA periodontal ligament (PF) afferents gave rise to large and circumscribed arbors in Vi, although the arbors in Vc were smaller and less dense. The present study demonstrated significant functional and morphological relationships for primary afferents in Vi and Vc, thus suggesting that sensory information from each of the distinct fiber or functional classes is processed in a characteristic manner in the individual nuclei. © Wiley‐Liss, Inc.
Human fetal neocortical tissue grafted to rat brain cavities survives, leads to reciprocal nerve fiber growth, and accumulates host IgG
Authors: Humpel Christian , Bygdeman Marc , Olson Lars , Strömberg Ingrid 
Published: January 2005

AbstractThe human‐to‐rat xenograft approach offers possibilities to study aspects of primate cortex development and function without monkeys. Human fetal cortical tissue was grafted to prepared cortical cavities of immunosuppressed host rats. Fetal tissue fragments were collected after routine low‐pressure vacuum aspiration abortions performed in the first trimester of gestation. Human derived neurons and human nerve fiber outgrowth were visualized by immunohistochemistry with antibodies against human neurofilament protein 70 kD (hNFP70). Ingrowth from rat host striatum or cortex into the grafts was analyzed by immunohistochemistry with antibodies against tyrosine hydroxylase. Astrocytes were evaluated by immunohistochemistry with antibodies against glial fibrillary acidic protein. The grafts grew into different sizes (1–10 mm in diameter) and contained large numbers of hNFP70‐positive nerve fibers. All grafts gave rise to outgrowth of hNFP70‐positive fibers into the host with partly a cortical layering; layers III and IV received a majority of the human fibers. In several cases, the graft‐derived nerve fibers entered the host brain at restricted areas, while there was no crossing over of nerve fibers at the rest of the graft‐host interface. Tyrosine hydroxylase‐positive fibers were usually not abundant in the grafts. Interestingly, cases of massive ingrowth occurred from host striatum into the graft in a pattern suggesting “permissive sites” at the graft‐host interface in the same way as outgrowth from graft to host was found. Additionally, tyrosine hydroxylase‐immunoreactive fibers from host cortex were found to grow into the transplant. Glial fibrillary acidic protein immunoreactivity was increased at the interfaces between graft and host cortex or host striatum. Immunohistochemistry using antibodies against rat IgG indicated the presence of rat IgG within the grafts, and in bordering areas of host brain, possibly indicating a defective graft‐host barrier. Taken together, these results show that human cortical‐tissue pieces grafted to cortical cavities of immunosuppressed rats survive grafting and develop, and that reciprocal nerve fiber growth between grafts and hosts occur. Human cortical neurons can grow into the rat host brain in a pattern which is partly determined by host cortical architecture. © Wiley‐Liss, Inc.
Differential distribution of amyloid protein precursor immunoreactivity in the rat brain studied by using five different antibodies
Authors: Beeson James G. , Shelton Earl R. , Chan Hardy W. , Gage Fred H. 
Published: January 2005

AbstractThe β‐amyloid or A4 protein is found deposited in neuritic plaques and neurofibrillary tangles in Alzheimer's disease (AD) affected brains and in the brains of adults with Down's Syndrome. The precursor to this 42 amino acid protein is the 695 amino acid long amyloid protein precursor (APP‐695). Two additional APP species, APP‐751 and APP‐770, each contain a 56‐amino‐acid insert sequence that is analogous to Kunitz protease inhibitors. APP mRNA is widely distributed in both the human and rat brain, although the adult rat does not develop mature amyloid pathology. In this study we used antibodies against the N‐terminus, junction site (unique to APP‐695) insert sequence (unique to APP‐751,‐770), A4 region, and C‐terminus of APP to immunolabel sections from throughout the young adult rat brain. From these results we constructed maps of the staining pattern of each antibody. We found that APP is widely distributed throughout the brain, that labelling is predominantly neuronal in character, and that there is marked variation among the antibodies in the extent of labelling, the particular cell populations stained, and the structures labelled within individual cells. The differential staining patterns observed with the five different antibodies suggest that the way APP is processed differs from one region to another and within different compartments in the cell. The specificity of the antibodies was established by Western blot analysis, in which APP species of approximately 95 and 110 kD were found. Our findings on the distribution of APP provide a foundation for further investigations into the normal role of APP and the pathogenesis of AD. © 1994 Wiley‐Liss, Inc.
Interplay between the dendritic trees of alpha and beta ganglion cells during the development of the cat retina
Authors: Deplano S. , Ratto G. M. , Bisti S. 
Published: January 2005

AbstractWe have analyzed the effect of a small lesion to the retina of a two‐day‐old kitten and observed that after degeneration of ganglion cells whose axons were severed, a restricted region of the retina remained depleted of cells. Cells located near the borders of the depleted zone showed an abnormal elongation of dendrites towards the bare area. By means of a computer‐aided system, we analyzed the whole population of cells at the two borders, and in agreement with previous data found that the effect was most prominent at the border and progressively decreased to eventually disappear at a distance of approximately 500 μm. The distance from the border, however, is not the only factor to influence the degree of asymmetry; with comparable distances, the vicinity of an α‐cell reduces the projection of the β‐cell dendrites toward the empty area. We suggest that the organization of the adult retinal pattern is also influenced by interactions occurring between dendrites of different classes of ganglion cells. © 1994 Wiley‐Liss, Inc.
Development of interneurons with ipsilateral projections in embryonic rat spinal cord
Authors: Silos‐Santiago Inmaculada , Snider William D. 
Published: January 2005

AbstractConsiderable progress has been made in recent years in identifying molecules with restricted expression in mammalian spinal cord at early developmental stages. However, the significance of the different expression patterns for most of these molecules is nuclear because so little is known about the development of various classes of spinal interneurons. Recently, we have characterized the development of rat spinal cord interneurons with an axon that crosses in the ventral commissure (Silos‐Santiago and Snider, J. Comp. Neurol., 325:514, 1992). In the current study, we describe the morphological development of ipsilaterally projecting spinal interneurons in laminae V–VIII of the thoracic spinal cord. These neurons were labelled by retrograde lateral diffusion of DiI after crystals were placed in various locations in the embryonic thoracic cord.By E14, approximately 48 hours after the first interneurons are generated, eight different groups of ipsilateral interneurons are present in the spinal cord. By E15, these groups of ipsilateral interneurons have reached distinct locations within the gray matter. Even at this early stage, different groups of cells have elaborated characteristic dendritic arborizations. By E19, at least 17 different types of ipsilateral interneurons can be identified on the basis of location and dendritic morphology. In general, ipsilateral interneurons are located more dorsally and laterally than commissural interneurons at all stages of embryonic development. Furthermore, in comparison with commissural neurons, fewer ipsilateral interneurons have dendritic arbors with a mediolateral orientation in the transverse plane.This work demonstrates that rat embryonic spinal cord contains a large number of morphologically distinct classes of interneurons that extend axons into the ipsilateral lateral funiculus. These neurons can be distinguished from commissural neurons on the basis of location and morphology. These results, taken together with those from our previous study, provide a framework for the localization of gene expression to different classes of spinal interneurons at early developmental stages. © 1994 Wiley‐Liss, Inc.
Hindlimb sensory neuron number increases with body size
Authors: St. Wecker Peter G. R. , Farel Paul B. 
Published: January 2005

AbstractAs an animal grows, its sensory systems face the task of maintaining sensitivity and discrimination in peripheral fields that are continually enlarging. Without the addition of neurons, existing cells would have to innervate a wider skin area, leading to a decrease in the precision with which stimuli are localized. Neurons were counted in the three dorsal root ganglia (DRGs) that innervate the hindlimb of the bullfrog (Rana catesbeiana). Profiles of neuronal nuclei containing the single nucleolus found in these cells were counted in every third section of serially cut ganglia. This means of assessing neuron number was validated by comparing these profile counts with three‐dimensional reconstructions of sensory neurons. Large frogs (10–17 cm) had more than twice as many DRG neurons as small frogs (3.3–5 cm). The rate of increase was greatest between 3 and 8 cm, when over 1,300 hindlimb sensory neurons were added for each 1 cm increase in body length. The possibility that selective survival of frogs with many neurons biases estimates of mean neuron number was ruled out by the finding that frogs drawn from the same closed population, half of which were sacrificed immediately and half of which were sacrificed after 1 year's survival, showed expected differences in neuron number. Horseradish peroxidase applied to particular hindlimb nerves retrogradely labeled more neurons in large frogs than small frogs, supporting the hypothesis that added neurons extend their axons to the periphery.No evidence of tritium labeling was found following injection of 3H‐thymidine (a marker of DNA synthesis) every third day for 20–22 weeks, a period over which, on the basis of changes in body length, substantial numbers of neurons were likely added. These results, combined with previous studies of motoneuron addition in the lumbar lateral motor column, are consistent with the hypothesis that the population of sensory neurons is augmented by late differentiation of existing precursor cells. © 1994 Wiley‐Liss, Inc.
Quantitative morphological analysis of the cerebellar nuclei in normal and lurcher mutant mice. I. Morphology and cell number
Authors: Heckroth John A. 
Published: January 2005

AbstractThe present study indicates that the cerebellar nuclei of the mouse are essentially identical in structure with those described in the rat, and that the atrophic cerebellar nuclei in lurcher mutant mice exhibit a comparable anatomical organization. A quantitative estimate of the atrophy observed in the cerebellar nuclei of the adult lurcher mutant mouse reveals an overall 60% decrease in volume. Cell counts in the wild‐type cerebellar nuclei reveal a total of 8,528 principal neurons and 10,203 small neurons. The ratio of small/principal neurons is 0.5 in the fastigal nucleus and between 1 and 1.5 in other subdivisions. In lurcher, the principal neurons are slightly reduced in number (−20%) in the nuclear complex, while the population of small neurons is reduced by 37% in the interposed and dentate nuclei, but is unchanged in the fastigal nucleus. These results suggest that the massive deafferentation of the cerebellar nuclei that occurs between 10 and 30 days of age in lurcher mutants has a relatively mild effect on the principal cerebellar nuclear neurons. In the population of small neurons, however, the effect of deafferentation may be exacerbated by a secondary retrograde transneuronal degeneration brought on by the severe degeneration of inferior olivary neurons and cerebellar cortex in this mutant. © 1994 Wiley‐Liss, Inc.
Distribution of myomodulin‐like immunoreactivity in the adult and developing ventral nervous system of the locust Schistocerca gregaria
Authors: Swalles Lesley S. , Evans Peter D. 
Published: January 2005

AbstractThe distribution of myomodulin‐like immunoreactivity in the ventral nervous system of an insect, the locust Schistocerca gregaria, both in the adult and during development, is described. The result suggest the presence of a novel modulatory system in insects which uses myomodulin‐like neuropeptides. The study also indicates that the myomodulins, which were first identified in mollusks, may represent another interphyletic family of neuropeptides.In the suboesophageal ganglion, immunoreactive cells occur in five groups. The processes from the two anterior ventral midline groups of cells projects to the corpora allata via nervi corpora allata II. Thus myomodulin‐like neuropeptides may be involved in the control of the release of juvenile hormone from the corpora allata.The thoracic ganglia contain three groups of immunoreactive cells, including a bilaterally symmetrical group of 12–15 posterior lateral cells, which project to the median nerve and its neurohaemal organs, suggesting a possible neurohaemal role for myomodulin‐like peptides. Each thoracic neuromere also contains a single, intensely stained, dorsal unpaired median (DUM) cell that may correspond to the so‐called H cell. In the abdominal ganglia, the staining shows sexual dimorphism, both in terms of the number of dorsal and ventral midline cells stained and in terms of the distribution of their immunoreactive processes.Myomodulin‐like immunoreactivity is one of the earliest neurotransmitter/neurohormone phenotypes detectable during the development of the locust nervous system. It first appears in the single DUM cells in each of the thoracic neuromeres at 50% development, and the complete adult pattern of staining is present at 85%‐90% of development. © 1994 Wiley‐Liss, Inc.
Synaptic innervation of neurons in the internal pallidal segment by the subthalamic nucleus and the external pallidum in monkeys
Authors: Smith Y. , Wichmann T. , DeLong M. R. 
Published: January 2005

AbstractIn order to better understand the way by which the subthalamic nucleus interacts with the globus pallidus to control the output of the basal ganglia, we carried out a series of experiments to investigate the pattern of synaptic innervation of the pallidal neurons by the subthalamic terminals in the squirrel monkey. To address this problem we used the anterograde transport of biocytin.Following injections of biocytin in the subthalamic nucleus, rich plexuses of labelled fibres and varicosities formed bands that lay along the medullary lamina in both segments of the ipsilateral pallidum. At the electron microscopic level, two populations of bioctyin‐containing terminals were identified in the internal pallidum (GPi). A first group of small to medium‐sized terminals (type 1) mean cross‐sectional area ±S. D. = 0.41 ± 0.04 μm2contained round vesicles and formed asymmetric synapses with dendritic shafts (95%) of mixed sizes (maximum diameter ranging from 0.3 to 4.0 μm) and spine‐like structures (5%). This second group of terminals (type 2) contained pleiomorphic vesicles, had a larger cross‐sectional area (mean ± S. D. = 0.9 ± 0.4 μm2) and formed symmetric synapses predominantly with perikarya (41%) and large dendrites (57%). In some cases, the two types of terminals converged at the level of single GPi neurons. Postembedding immunogold method revealed that the type 2 terminals displayed gamma‐aminobutyric acid (GABA) immunoreactivity, whereas the type 1 terminals did not. In the external pallidum (GPe), injections in the subthalamic nucleus labelled both type 1 or type 2 terminals. However, the labelled type 2 boutons were much less abundant in GPe than in GPi. The presence of biocytin‐labelled perikarya in GPe and the fact that the type 2 terminals displayed GABA immunoreactivity led us to suspect that these terminals were derived from axons of GPe neurons. In agreement with this hypothesis, injctions ofPhaseolus vulgaris‐leucoagglutinin (PHA‐L) in GPe labelled terminals in GPi that displayed the morphological features and a pattern of synaptic organization similar to the type 2 terminals.In conclusion, the results of our study demonstrate that the subthalamopallidal terminals form asymmetric synapses that are distributed along the dendritic tree of GPe and Gpi neurons. In contrast, the GPe projection to GPi give rise to large GABA‐containing terminals that form symmetric synapses predominantly with the proximal region of pallidal neurons. Because the GABAergic axon terminals from GPe form synapses onto the perikarya and proximal dendrites of GPi neurons, the Gpe input is in a strategic position to reduce the excitatory influence generated more distally on the dendritic tree by the subthalamic nucleus. © 1994 Wiley‐Liss, Inc.
Differential expression of keratins in goldfish optic nerve during regeneration
Authors: Fuchs Chana , Druger Robert K. , Glasgow Eric , Schechter Nisson 
Published: January 2005

AbstractThe goldfish visual pathway, unlike the visual pathway of higher vertebrates, retains continuous growth and development throughout life and is capable of functional regeneration. The structure and expression of proteins that support the physiological attributes of this system are of interest. Glial cells in this pathway express keratins as the predominant intermediate filament proteins rather than the expected glial fibrillary acidic protein. Previously we identified and characterized cDNA clones representing two type I keratins from the goldfish optic nerve, GK48 and GK49. The GK48 protein is the type I keratin partner to the type II keratin ON3, while the GK49 protein is expressed in a different cell type. Here, we extend our studies on the expression of mRNA for the GK48, GK49, and ON3 proteins at the early stages of optic nerve regeneration. Rnase protection assays show that at 10 days post‐crush, there is no overall change in levels of mRNA for these proteins as compared to uncrushed control nerves and nerves from unoperated fish. In addition, we show by in situ hybridization that the GK49 protein shows no changes in its distribution of mRNA in the optic nerve after crush. In contrast, the level of GK48 and ON3 mRNA are greatly reduced within the crush zone. However, these two mRNAs are differentially expressed at different time points during regeneration, with GK48 mRNA appearing in the crush zone before ON3. These results indicate that the mRNA for the GK48 and ON3 proteins are differentially regulated during regeneration and that these two proteins are expressed in a different cell type from the GK49 protein. © 1994 Wiley‐Liss, Inc.