bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology and dendritic domains of neurons in the lateral parabrachial nucleus of the rat
Authors: Herbert Horst , Bellintani‐Guardia Breno 
Published: January 2005

AbstractThe present study provides a description of the dendritic morphology and the dendritic domains of neurons in the lateral parabrachial nucleus (PB) of the rat. The cells were intracellularly stained in vitro with Lucifer yellow. A subpopulation of these cells was characterized beforehand as neurons projecting to the amygdaloid complex by retrograde transport with rhodamine beads.With respect to their dendritic arborization, different types of “spatially” organized PB neurons were discriminated. One major cell type in the external lateral PB (PBel) is characterized by long, elongated dendritic trees that are preferentially oriented parallel to the superior cerebellar peduncle. The majority of their dendrites appears to respect subnuclear boundaries, yet their distal dendrites often exceed the limits of the PBel to encroach upon adjacent subnuclei located dorsally and ventrolaterally to the PBel. Another prominent cell type in the PBel has fairly small and locally restricted dendritic trees that are also elongated, running with their main axis from ventrolateral to dorsomedial. The dendrites of the majority of these neurons apparently stay within the confines of the PBel. A distinct group of neurons is found in the ventral portion of the PBel. The majority of their dendrites is mediolaterally oriented and not confined to the PBelsubnucleus. In addition, we found a smaller number of neurons scattered within the lateral PB whose dendrites do not show a preferential orientation but travel across subnuclear boundaries into several different PB subnuclei.Our data show that the dendrites of a large proportion of neurons in the lateral PB either stay within the confines of a particular subnucleus or slightly extend across subnuclear limits. In any case, they appear to match with terminal territories of afferent axons and, thus, maintain the functional specificity of inputs by their relay through the PB. In contrast, PB neurons that extend their dendrites across subnuclear boundaries or known terminal territories are likely to receive inputs of different qualities from a variety of sources and therefore transmit a more general, integrated signal to the forebrain. © 1995 Wiley‐Liss, Inc.
Commissural fibers may guide cholinergic neuronal migration in developing rat cervical spinal cord
Authors: Phelps Patricia E. , Vaughn James E. 
Published: January 2005

AbstractThe present investigation examines the role of intercellular, relationships in the guidance of neuronal migration in embryonic rat cervical spinal cord. A “U‐shaped” group of cholinergic neurons, was first detected on embryonic days (E) 15. 5–16 surrounding the ventral proliferative zone. At these stages, no cholinergic cells were observed in the dorsal spinal cord, but by E17, many of the “U‐shaped” group of cholinergic cells appeared to have translocated dorsally, to become the cholinergic dorsal horn cells seen in older animals. Between E16 and E17, these choline acetyltransferase (ChAT)‐immunoreactive cells displayed primitive processes oriented dorsoventrally, suggesting migration along that axis. Two early forming substrates present in embryonic spinal cord have been implicated in the guidance of other populations of migrating neurons: glial cells organized in radial arrays and commissural axons aligned along the dorsoventral axis. Involvement of the commissural fibers with cholinergic cell migration seems more likely because the fibers and the translocation pathway have similar orientations. In double‐labeling immunocytochemical studies of E15. 5–17 spinal cord, some immature ChATcontaining neurons were directly adjacent to commissural fibers, as identified by SNAP/TAG‐1 immunoreactivity. The temporal and spatial coincidence of developing cholinergic neurons and commissural axons is consistent with the hypothesis that these neurons could use commissural fibers as migratory guides. In addition, conventional electron micrographs were examined to determine if immature neuronal profiles were physically apposed to commissural axons. Immature neurons with leading and trailing processes oriented dorsally and ventrally, respectively, were embedded within and aligned along bundles of commissural fibers or along other similarly oriented neurons. This direct apposition of immature cells to the surfaces of commissural axons and other bipolar neurons is consistent with the hypothesis that the “U‐shaped” group of cholinergic neurons may use commissural axons and other cohort neurons for guidance during their dorsal migration.
Synaptic organization of the interstitial subdivision of the nucleus tractus solitarii and of its laryngeal afferents in the rat
Authors: Mrini Abdelghani , Jean André 
Published: January 2005

AbstractThe nucleus tractus solitarii, the first central relay for gustatory and a variety of visceral afferents, is also an integrative center for numerous functions. Its interstitial subdivision is involved in swallowing and respiratory reflexes. The ultrastructural characteristics of this subdivision and of its laryngeal afferents were investigated in adult rat by a serial‐section study and by application of wheat germ agglutinin‐horseradish peroxidase conjugate to the peripheral afferent fibers. The interstitial subnucleus contained scattered small neuronal cell bodies with such ultrastructural features as a large nucleus with deep indentations and an organellepoor cytoplasm. On the basis of their size and vesicular content, the axon terminals were classified into three categories. Group I and group II terminals were small or large, respectively, and contained mainly small, round, and clear synaptic vesicles. Group III terminals were also small but contained small, pleomorphic, and clear vesicles. Axodendritic synapses were the most numerous. They were either asymmetrical, comprised of group I and II terminals, or symmetrical, comprised of group III terminals. More than 50% were part of complex synaptic arrangements in the form of rosettes or glomeruli. Axosomatic contacts involved both group I and group III terminals and were always symmetrical. A high frequency of axoaxonic synapses was found. They were symmetrical, comprised of group III terminals on group I or II terminals. Different types of symmetrical synaptic contacts made by dendrites were also found. This study indicates also that the ipsilateral interstitial subdivision constitutes the preferential site of termination for superior laryngeal afferents. The labeled axon terminals belonged exclusively to groups I and II and were involved in both axodendritic and axodxonic synapses. Some of the axodendritic synapses were part of rosettes or glomeruli. All these synaptic arrangements may be considered a morphological substrate for important processing of afferent information in the nucleus tractus solitarii. They may account for some of the integrative functions of the interstitial subnucleus such as physiological processes triggered from the superior laryngeal nerve.
Model of forebrain regionalization based on spatiotemporal patterns of POU‐III homeobox gene expression, birthdates, and morphological features
Authors: Alvarez‐Bolado G. , Rosenfeld M. G. , Swanson L. W. 
Published: January 2005

AbstractIn situ hybridization was used to map spatiotemporal expression patterns of the four known intronless POU‐III transcription factor genes Brn‐1, Brn‐2, Brn‐4, and Tst‐1 in the developing rat forebrain vesicle, beginning on embryonic day 10. The results indicate that the proliferation layers (ventricular and subventricular) and mantle layer of the forebrain neural tube each display a strikingly unique pattern of regionalized POU‐III expression. Within a particular region, or layer within a region, none to all four of the mRNAs may be detected, and during development a particular mRNA in a particular region displays one of five expression patterns, or a combination of these patterns, which may be described as conserved, lost, transient, acquired, or redeployed expression. In the developing brain as a whole, Brn‐1 and Brn‐2 early on display somewhat different spatial expression patterns that converge to essential identity in the adult, whereas Brn‐4 expression is initially broad and becomes much more restricted in the adult, and Tst‐1 expression expands greatly through development. Usually, though not always, expression patterns tend to correlate with major histological features in the forebrain (often internal or external sulci associated with proliferation zones), and little evidence for waves of expression moving through the whole forebrain over time was obtained. Thus, clear differences in hybridization intensity often are observed between the cerebral cortex, basal telencephalic nuclei, hypothalamus, ventral thalamus, dorsal thalamus, and pretectal region. In contrast, transverse bands of hybridization extending from the roof to the floor of the forebrain, corresponding to proposed neuromeres, were not observed with these probes. The results suggest that POU‐III transcription factors help define specific regions in the early neuroepithelium as well as different cellular phenotypes in the ventricular, subventricular, and mantle layers of specific regions later in development. Thus, the functions of these regulatory proteins may be different in proliferating neuroepithelial cells, young neurons, and mature neurons and appear to be region‐specific.
D1 and D2 dopamine receptor gene expression in the rat striatum: Sensitive cRNA probes demonstrate prominent segregation of D1 and D2 mRNAS in distinct neuronal populations of the dorsal and ventral striatum
Authors: Le Moine Catherine , Bloch Bertrand 
Published: January 2005

AbstractThe postsynaptic effects of dopamine in the striatum are mediated mainly by receptors encoded by D1, D2, and D3 dopamine receptor genes. The D1 and D2 genes are the most widely expressed in the caudate‐putamen, the accumbens nucleus, and the olfactory tubercle. Several anatomical studies, including studies using in situ hybridization with oligonucleotide and cDNA probes, have suggested that D1 and D2 receptors are segregated into distinct efferent neuronal populations of the striatum: D1 in substance P striatonigral neurons and D2 in enkephalin striatopallidal neurons. In contrast, on the basis of several in vivo and in vitro studies, other authors have suggested the existence of an extensive colocalization of D1 and D2 in the same striatal neurons. Our study was undertaken in order to analyze in detail the expression of the D1 and D2 receptor genes in the efferent striatal populations, with special reference to the various striatal areas, and to yield insights into the question about D1 and D2 mRNA localization in the striatum. We have, therefore, used highly sensitive digoxigenin‐and 35S‐labeled cRNA probes to address this question. The present results demonstrate that the D1 and D2 receptor mRNAs are segregated, respectively, in substance P and enkephalin neurons in the caudate‐putamen and accumbens nucleus (shell and core) and in the olfactory tubercle (for their largest part). A very small percentage of neurons may coexpress both genes. These results confirm that the D1 and D2 receptor genes are expressed in distinct populations of striatal efferent neurons in the normal adult rat. © 1995 Wiley‐Liss, Inc.
Distribution of natriuretic peptide precursor mRNAs in the rat brain
Authors: Langub Moises C. , Watson Robert E. , Herman James P. 
Published: January 2005

AbstractAtrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C‐type natriuretic peptide (CNP) represent members of a recently discovered neuropeptide family involved in central regulation of endocrine and autonomic functions. The present study employed an in situ hybridization approach to provide the first detailed comparative mapping of ANP, BNP, and CNP mRNAs in brain. Results indicate that ANP mRNA is highly expressed in anterior olfactory nuclei, limbic cortices, dorsal endopiriform nucleus, hippocampal subfield CA1, cortical amygdaloid nuclei, medial habenula, anteroventral periventricular and arcuate nuclei, periventricular stratum, zona incerta, mammillary nuclei, inferior olive, nucleus ambiguus, and pontine paragigantocellular nuclei. CNP mRNA is expressed at highest levels in olfactory nuclei, limbic cortices, dorsal endopiriform nucleus, hippocampal subfields CA1–3, anteroventral periventricular and arcuate nuclei, and numerous brainstem regions (including the pontine, lateral reticular, solitary tract, prepositus hypoglossal, and spinal trigeminal nuclei). Positive labeling for BNP mRNA was not observed in brain. The presence of both ANP and CNP mRNA in the same regions of distinct nuclei (e.g., the anteroventral periventricular and arcuate nuclei) suggests the potential for coexpression. Overall, the present data are consistent with a prominent role for both ANP and CNP in neuroendocrine regulation and central cardiovascular integration. The extensive localization of ANP and/or CNP mRNA in olfactory nuclei, limbic cortex, hippocampus, amygdala and diencephalic limbic relays further indicate a putative role for ANP and CNP as neuromodulators of olfactory/limbic information processing. © 1995 Wiley‐Liss, Inc.
Molecular compartmentation expressed in cerebellar cultures in the absence of neuronal activity and neuron‐glia interactions
Authors: Seil Fredrick J. , Johnson Marilyn L. , Hawkes Richard 
Published: January 2005

AbstractThe purpose of the study was to determine if zebrin compartmentation developed in permanently isolated cerebellar cultures, in the presence of agents that block neuronal activity and in the absence of myelination and astrocytic ensheathment of Purkinje cells. Parasagittally oriented organotypic cultures derived from newborn mice and carefully undercut at explantation to exclude extracerebellar afferents were subjected to three conditions: (1) Some were maintained in standard nutrient medium; (2) some were chronically exposed to tetrodotoxin and elevated levels of magnesium to block neuronal activity; and (3) some were exposed to cytosine arabinoside for the first 5 days in vitro (DIV) to destroy granule cells and oligodendrocytes and functionally compromise astrocytes, so that the astrocytic survivors did not ensheath Purkinje cells. Cultures fixed as whole‐mount preparations were reacted with antibody to zebrin II. Cultures that were cryostat sectioned were dually reacted with antibody to zebrin II and calbindin. Groups of zebrin+ and zebrin− Purkinje cells were evident after 14 DIV in all of the experimental conditions, indicating that zebrin compartmentation developed (1) in isolated cerebellar explants, (2) in the absence of neuronal activity, and (3) in the absence of neuron‐glia interactions such as myelination and glial ensheathment of Purkinje cell somata and dendrites. These results are consistent with the concept that expression of the zebrin+ and zebrin− phenotypes is an intrinsic property of Purkinje cells. The fact that zebrin expression seems to depend on an intrinsic program of differentiation in Purkinje cells suggests some role for zebrin compartmentation in cerebellar function. © 1995 Wiley‐Liss, Inc.
Autoradiographic localization of opioid receptors in vocal control regions of a male passerine bird (Junco hyemalis)
Authors: Gulledge Cynthia C. , Deviche Pierre 
Published: January 2005

AbstractPrevious studies have found opioid peptide‐like immunoreactivity in avian vocal control regions, but whether these regions contain receptors for opioid peptides has not been examined. To address this question, we used quantitative in vitro autoradiography to determine the anatomical distribution and to measure the densities of μ, δ, and κ opioid receptors in vocal control regions (area X higher vocal center, and nucleus intercollicularis) of adult male dark‐eyed juncos (Junco hyemalis). To evaluate whether opioid receptor densities in these regions depend on the activity of the reproductive system, we also measured these densities in birds collected during the spring, summer, and fall. We found area X, the higher vocal center, and nucleus intercollicularis to contain the three receptor types under study, but opioid receptor densities did not vary seasonally in any of these regions. The presence of specific opioid receptors in avian vocal control regions suggests the participation of opioids in the control of vocal behavior. This participation may consist of short‐term (e. g., auditory processing) and/or long‐term (e. g., neuronal plasticity) influences. © 1995 Wiley‐Liss, Inc.
Specificity of rabies virus as a transneuronal tracer of motor networks: Transfer from hypoglossal motoneurons to connected second‐order and higher order central nervous system cell groups
Authors: Ugolini Gabriella 
Published: January 2005

AbstractThe specificity of transneuronal transfer of rabies virus [challenge virus standard (CVS) strain] was evaluated in a well‐characterized neuronal network, i. e., retrograde infection of hypoglossal motoneurons and transneuronal transfer to connected (second‐order) brainstem neurons. The distribution of the virus in the central nervous system was studied immunohistochemically at sequential intervals after unilateral inoculation into the hypoglossal nerve. The extent of transneuronal transfer of rabies virus was strictly time dependent and was distinguished in five stages. At 1 day postinoculation, labelling involved only hypoglossal motoneurons (stage 1). Retrograde transneuronal transfer occurred from 2.0–2.5 days postinoculation (stage 2). In stages 2–4, different groups of second‐order neurons were labelled sequentially, depending on the strength of their input to the hypoglossal nucleus. In stages 4 and 5, labelling extended to several cortical and subcortical cell groups, which can be regarded as higher order because they are known to control tongue movements and/or to provide input to hypoglossal‐projecting cell groups. The pattern of transneuronal transfer of rabies virus resembles that of alpha‐herpesviruses with regard to the nonsynchronous labelling of different groups of second‐order neurons and the transfer to higher order neurons. In striking contrast to alpha‐herpesviruses, the transneuronal transfer of rabies isnotaccompanied by neuronal degeneration. Moreover, local spread of rabies from infected neurons and axons to adjoining glial cells, neurons, or fibers of passage does not occur. The results show that rabies virus is a very efficient transneuronal tracer. Results also provide a new insight into the organization of cortical and subcortical higher order neurons that mediate descending control of tongue movements indirectly via hypoglossal‐projecting neurons. © 1995 Wiley‐Liss, Inc.
Expression of polysialylated N‐CAM in the central nervous system of adult canaries and its possible relation to function
Authors: Rousselot P. , Nottebohm F. 
Published: January 2005

AbstractPolysialylated neuronal cell adhesion molecule (PSAqN‐CAM) is a cell surface molecule associated with neurons that undergo changes in configuration or spatial translocation. In both cases, this molecule is thought to reduce the adhesivity of these cells or of their processes, which can thereby insinuate themselves into the existing parenchyma. We used a monoclonal antibody specific to PSA to offer what we believe is the first account of the distribution of PSA‐N‐CAM in the adult songbird brain. This antibody stained a diversity of cell classes and processes, as follows: (1) a subset of ventricular zone cells; (2) migrating cells thought to be neuroblasts; (3) a subset of differentiated neurons; (4) some brain surface astrocytes; (5) some tanycytes; (6) the neuropil of some regions; (7) some axonal fibers; and (8) possibly some synapses. Our results demonstrate also, for the first time, the wide distribution of a very numerous population of migrating cells in the telencephalon and the seasonal regulation of PSA‐Nq‐CAM expression in a part of the adult brain known to undergo seasonal changes in cell recruitment and function. However, we did not find PSA‐N‐CAM associated with young migrating cells in the high vocal center (HVC), nor was there PSA‐N‐CAM in the robust nucleus of the archistriatum (RA), which is known to receive new axonal endings from HVC. In these instances spatial translocation may occur with the assistance of other surface molecules. © 1995 Wiley‐Liss, Inc.
Direct projections from the dorsolateral pontine tegmentum to pudendal motoneurons innervating the external urethral sphincter muscle in the rat
Authors: Ding Yu‐Qiang , Takada Masahiko , Tokuno Hironobu , Mizuno Noboru 
Published: January 2005

AbstractDirect projections from the dorsolateral pontine tegmentum to pudendal motoneurons innervating the external urethral sphincter and the external anal sphincter muscles were examined in the rat by the tract‐tracing methods utilizing retrograde transport of cholera toxin B subunit and anterograde transport of biotinylated dextran amine. The dorsolateral pontine tegmental region, corresponding to the micturition reflex center of Barrington, was confirmed to send bilaterally, with an ipsilateral dominance, projection fibers to the spinal parasympathetic nucleus (inferior intermediolateral nucleus). The micturition reflex center of Barrington, however, did not seem to send many projection fibers to the ventral horn of the lumbosacral cord segments, whereas the region immediately ventral to the micturition reflex center of Barrington was found to send bilaterally, with a contralateral dominance, projection fibers to the dorsolateral group of pudendal motoneurons in both the male and female rats. In the female rat, the dorsolateral group of pudendal motoneurons are comprised primarily of motoneurons that innervate the external urethral sphincter muscle. The dorsomedial group of pudendal motoneurons, which contain motoneurons that innervate the external anal sphincter and the bulbocavernosus muscles, did not seem to receive major projections from the dorsolateral pontine tegmental regions. It was also observed that the locus coeruleus sent some projection fibers bilaterally to the spinal parasympathetic nucleus but only a few to the ventral horn of the lumbosacral cord segments. Thus, the present results indicate that the dorsolateral group of pudendal motoneurons containing those innervating the external urethral sphincter muscle receive pontospinal projection fibers mainly from the dorsolateral pontine tegmental region immediately ventral to the micturition reflex center of Barrington. © 1995 Wiley‐Liss, Inc.