bluuebunny/crossref_metadata_2025_split huggingface dataset:
Central projections of primary sensory neurons innervating different parts of the vibrissae follicles and intervibrissal skin on the mystacial pad of the rat
Authors: Arvidsson J. , Rice F. L. 
Published: January 2005

AbstractThe cell bodies and central projections of neurons innervating the vibrissae follicles and adjacent skin in the rat were investigated by retrograde and transganglionic transport of HRP. The cell bodies of neurons innervating the vibrissa follicle via the deep vibrissa nerve (DVN) were the largest, followed by those innervating the follicle via the superficial vibrissa nerve (SVN). The smallest cell bodies were those innervating the intervibrissal skin. The DVN neurons terminated centrally as an almost uninterrupted column through the trigeminal sensory nuclear complex. The DVN projections to nucleus caudalis and C1 dorsal horn were entirely restricted to laminae III, IV, and V. Besides the projections to lamina V, the DVN projections were strictly localized somatotopically at all levels replicating the peripheral organization of the vibrissae. The SVNs projected sparsely to midlevels of the main sensory nucleus but not to nuclei oralis and interpolaris. The main SVN projections appeared in laminae I‐III of nucleus caudalis. In addition, a small projection to lamina V was observed. The projections to laminae II and III were organized mediolaterally in a similar way as the DVN projections; those to laminae I and V were less restricted. The intervibrissal skin neurons projected sparsely to the caudal main sensory nucleus and to the border between nuclei oralis and interpolaris. The projections to nucleus caudalis were restricted to laminae I‐III and V and were organized in a similar way as the SVN projections.
Segment‐specific modifications of a neuropeptide phenotype in embryonic neurons of the moth, Manduca sexta
Authors: Wall John B. , Taghert Paul H. 
Published: January 2005

AbstractWe have studied differences in the development of segmentally homologous neurons to identify factors that may regulate a neuropeptide phenotype. Bilaterally paired homologs of the peripheral neuron L1 were identified in the thoracic and abdominal segments in embryos of the moth Manduca: each bipolar neuron arises at a stereotyped location and, at 40% of embryogenesis, projects its major process within the transverse nerve of its own segment. Shortly after the initiation of axonogenesis (∼41%), L1 homologs in all but the prothoracic segment (T1) were labelled specifically by an antiserum to the molluscan neuropeptide Phe‐Met‐Arg‐Phe‐NH2 (authentic‐ FMRFamide). Levels of peptide‐immunoreactivity (IR) were comparable in all such segmental homologs up to the ∼60% stage of embryogenesis, whereupon two distinct levels of peptide IR were displayed: homologs in the three most rostral segments (T2, T3, and A1; [abdominal segment 1]) showed high levels and were called Type I L1 neurons; homologs in the more caudal segments (A2‐A8) typically showed low levels of IR and were called Type II L1 neurons. This segment‐specific difference represented mature differentiated states and was retained in postembryonic stages. Intracellular dye fills of embryonic L1 neurons revealed that the morphogenesis of the Type I and II L1 neuron homologs was similar until ∼48% of embryogenesis; thereafter it differed in two salient ways: (1) the cell bodies of Type II L1 neurons migrated ∼150 m̈m laterally from their point of origin, and (2) the distal processes of the Type II L1 neurons contacted the heart, whereas those of Type I L1 neurons did not. Ultrastructural studies of both mature and developing L1 homologs showed that the FMRFamide‐like antigen(s) localized specifically to secretory granules. Further, whereas the secretory granules in segmental homologs appeared similar initially (i.e., at ∼50% of development), following the establishment of segment‐specific differences, secretory granules found in mature Type I and II L1 neurons were cell type‐specific.
Single dopaminergic nigrostriatal neurons form two chemically distinct synaptic types: Possible transmitter segregation within neurons
Authors: Hattori T. , Takada M. , Moriizumi T. , Van Der Kooy D. 
Published: January 2005

AbstractThese experiments were designed to examine a paradox present in the literature with regard to the fine structure of nigrostriatal dopamine terminals within the rat striatum. Previous studies have shown that anterograde transport of tritiated labeled proteins from the substantia nigra to the striatum over short survival times primarily labels asymmetric synapses (and that these asymmetric synapses are preferentially vulnerable to selective dopaminergic neurotoxins such as 6‐hydroxydopamine). In contrast, fine structural immunohistochemical studies with antibodies to tyrosine hydroxylase and dopamine have consistently labeled primarily symmetric synapses en passant within the striatum. We have now confirmed that these two seemingly contradictory types of labeled synapses (radio‐ and immuno‐labeled) can both be present, but most often separate from one another, in single ultrathin sections. However, we also found that radiolabeled unmyelinated axons were usually double‐labeled by tyrosine hydroxylase immunohistochemistry. Employing longer survival times (10 days after the nigral isotope injections) in order to enhance the ratio of “enpassant” to terminal labeling produced a large increase in the occurrence of radiolabeled striatal axonal varicosities with the result that many symmetric synapses en passant were double‐labeled with both the autoradiographic and the immunohistochemical markers. Given that more than 95% of the nigrostriatal projection arises from dopamine fluorescent neurons, it would appear that both the asymmetric and symmetric terminals belong to the same type of neuron. Thus, we suggest that single dopaminergic neurons in the substantia nigra make two types of synaptic contact with striatal cells: (1) symmetric synapses en passant, which can be stained with tyrosine hydroxylase and dopamine and which contact dendritic spine necks, and (2) asymmetric terminal boutons of unknown chemical nature which end on dendritic spine heads. We conclude that both the asymmetric terminal and symmetric en passant synapses take origin from a single nigrostriatal dopaminergic neuronal population and that dopaminergic transmitter markers occur only in one of these synaptic types in the rat striatum.
Distribution of somatostatin receptors in the cat and monkey visual cortex demonstrated by in vitro receptor autoradiography
Authors: Rosier A. M. , Leroux P. , Vaudry H. , Orban G. A. , Vandesande F. 
Published: January 2005

AbstractSomatostatin (SRIF, S14) receptors in the cat and monkey visual cortex were visualized by means of in vitro autoradiography with an iodinated agonist of SRIF, [125I‐Tyr0, DTrp8]S14. The kinetics, performed on tissue sections, revealed an apparently single, saturable site (KD = 3.92 ± 0.31 10−10 M for the cat, and 3.82 ± 0.28 10−10 M for the monkey visual cortex) with pharmacological specificity for S14 and [DTrp]‐substituted S14. Autoradiography, performed on frontal sections of the cat and monkey visual cortex, revealed a heterogeneous regional and laminar distribution of SRIF receptor.In cat areas 17, 18, and 19, SRIF receptors occur mainly in the supragranular layers, although small interareal and intra‐areal differences are observed. The infragranular layers (V–VI) in area 19 contain a significantly higher proportion of SRIF receptors compared to both areas 17 and 18. In the antero‐ (AMLS) and posteromedial lateral suprasylvian area (PMLS), layers V and VI contain the highest proportion of SRIF receptors. This latter pattern is also observed in the area prostriata medially adjoining area 17 in the splenial sulcu.In the monkey visual cortex, areas 17 and 18 exhibit similar distribution patterns, SRIF receptors being primarily concentrated in layers V and V.Neither in the cat nor the monkey visual cortex could we observe significant differences in SRIF receptor distribution between different retinotopic subdivisions within one are.
Human olfactory epithelium in normal aging, alzheimer's disease, and other neurodegenerative disorders
Authors: Trojanowski John Q. , Newman Paul D. , Hill William D. , Lee Virginia M.‐Y. 
Published: January 2005

AbstractBy use of immunohistochemistry, we characterized the molecular phenotype of human olfactory epithelial (OE) cells and assessed the nature of the dystrophic olfactory neurites described initially in Alzheimer's disease (AD). Keratin 8 was present in all classes of OE cells. Sustentacular cells lacked other cell type specific polypeptides and were distinguished from neurons and basal cells because the latter two classes of OE cells expressed neural cell adhesion molecules (N‐CAMs) and microtubule associated proteins (MAPs), i.e., MAP5. Basal cells expressed nerve growth factor receptors (NGFRs), which distinguished them from olfactory neurons. Unlike their perikarya, olfactory axons expressed vimentin and GAP‐43, but not peripherin or neurofilament (NF) proteins. Olfactory nerves were distinguished from other axons because the latter were positive for all three NF subunits and peripherin, in addition to vimentin and GAP‐43.Dystrophic neurites in the OE were GAP‐43 positive, but they also expressed proteins that were not detected in normal olfactory nerves (i.e., synaptophysin, MAP2, tau, peripherin, NF proteins). Further, rare NF positive olfactory neurons gave rise to NF positive dystrophic neurites. These neurites were present in all 11 AD cases, 11 of 14 subjects with other neurodegenerative diseases, and 6 of 8 neurologically normal adult controls, but no dystrophic neurites were seen in 9 fetal and neonatal case.We conclude that the molecular phenotype of different human OE cells is distinct and that dystrophic olfactory neurites occur very frequently in neurologically normal adults. The relevance of these neurites to aging or specific disease processes remains speculativ.
Cytoarchitecture and intrafrontal connections of the frontal cortex of the brain of the hamadryas baboon (Papio hamadryas)
Authors: Watanabe‐Sawaguchi Kyoko , Kubota Kisou , Arikuni Tomio 
Published: January 2005

AbstractA study was made of the cytoarchitecture of the lateral and medial frontal cortex in the hamadryas baboon (Papio hamadryas). The frontal corticocortical connections of areas 46, 8, 6, and 4 were investigated by injection of wheat‐germ agglutinine conjugated to horseradish peroxiase (WGA‐HRP) into different regions of areas 46, 8, and 6. The lateral region of the frontal lobe of the baboon consists of broad areas of motor (area 4), premotor (area 6), and the dorsolateral prefrontal cortex, each of which is further divided into subdivisions with distinct cytoarchitectural features: areas 4a, 4b, 4c; 6aα, 6aβ, 6aγ, 6bα, and 6β; 8A and 8B; 45; 46 and 46ps; 9; 10; and 12. Although the frontal cortex of the baboon brain exhibits the same basic cytoarchitectural features as the frontal corticies of the cercopithecus (campbelli?) (Vogt and Vogt, '19) or the macaque (Walker, '40; Barbas and Pandya, '87, '89), the baboon frontal cortex is very different from that of the macaque and cercopithecus in terms of cytoarchitecture: (1) the baboon frontal cortex has an additional area, termed here “6aγ”, within area 6, which has cytoarchitectural characteristics that are intermediate between those of areas 6 and 8; (2) the aggregation of giant pyramidal cells (> 50 μm. in diameter) is found only in area 4a in the baboon, whereas such aggregates are found in areas 4a and 4b and, occasionally, in area 4c in the macaque; and (3) area 46 of the prefrontal cortex of the baboon can be subdivided into the cortex that surrounds the principal sulcus (area 46) and the upper and lower banks of the principal sulcus (area 46ps).Retrogradely WGA‐HRP labeled cells and anterogradely WGA‐HRP labeled terminals coexisted in the frontal cortex in a columnar fashion, indicative of a reciprocity among the connections. The frontal cortico‐cortical connections of areas 46, 8, 6, and 4 in the hamadryas baboon were organized as follows: (1) areas 46, 8, and 6 were connected to one another, (2) area 4 was connected only to area 6, and (3) these connections showed a gross ventrodorsal topography: the ventral regions of each of areas 46, 8, and 6 were connected more strongly to the ventral than the dorsal regions of the other areas; the dorsal regions of each of areas 46, 8, and 6 were connected more strongly to the dorsal than the ventral regions of the other areas. Moreover, the ventral region of area 6 was more strongly connected to the ventral than to the dorsal region of area 4, whereas the dorsal region of area 6 was more strongly connected to the dorsal than to the ventral region of area 4.
Reduced branching and length of dendrites detected in cervical spinal cord motoneurons of wobbler mouse, a model for inherited motoneuron disease
Authors: Ma Weiya , Vacca‐Galloway L. L. 
Published: January 2005

AbstractThe Wobbler mouse (wr) has been proposed as a model for human inherited motoneuron disease (infantile spinal muscular atrophy). The primary defect is thought to be in the motoneurons. Therefore we undertook a survey of the qualitative and quantitative changes occurring in the cervical spinal motoneurons of Wobbler mice during a late stage of the motoneuron disease compared with age‐ and sex‐matched normal phenotype (NFR/wr) littermates. The Rapid Golgi Method was applied. In control and Wobbler mice, four types of neurons were identified according to their dendritic patterns: multipolar, tripolar, bipolar, and unipolar cells. Unipolar cells were observed more often in the Wobbler specimens than the controls and may represent a final stage in the degeneration of other cell types with greater numbers of primary dendrites. Medium (300–999 μm2) and large (> 1,000 μm2) impregnated neurons (presumably alpha‐motoneurons) showed strong indications of cell degeneration, including statistically significant reductions in the measurements for dendritic length, distribution, and branching, as well as the number of spines. In contrast, the small (< 300 μm2) neurons showed only mild signs of degeneration, including slight reductions in dendritic length, but no significant differences appeared in the distribution and branching of dendrites, or in the number of spines. Instead, a small increase could be detected in the number of primary and secondary dendritic branches emanating from the small neurons, as well as in the number of dendritic spines. These findings suggest that sprouting may occur to a slight extent. Although previous studies document that swelling with subsequent vacuolation of motoneurons is the predominant feature characterizing the Wobbler disease, the mean soma area (μm2) calculated for the impregnated neurons of the Wobbler specimens showed no significant difference from the controls. It is hypothesized that the advanced signs of the Wobbler motoneuron disease are primarily reflected in the degeneration of the dendrites and spines on the medium and large alpha‐motoneurons. The small neurons (presumably a mixed population of gamma‐motoneurons, interneurons, and Renshaw cells) possess dendrites and spines that seem to be less affected, and instead show signs of sprouting.
Motor neurons supplying hindwing muscles of a grasshopper: Topography and distribution into anatomical groups
Authors: Siegler Melody V. S. , Phong Mario P. , Pousman Cynthia A. 
Published: January 2005

AbstractThe motor neurons supplying the dorsoventral wing muscles in the metathorax of the grasshopper Schistocerca americana were stained by backfilling muscle‐nerves with cobaltous chloride, which was then precipitated and intensified as silver sulfide. Stained motor neurons were examined in wholemounts and in sectioned ganglia. Two unifunctional muscles are innervated by a single motor neuron each, whereas four bifunctional muscles, involved in leg and wing movements, are innervated by two or three motor neurons each. Each of the motor neurons is in one of four identified anatomical groups. All members of a group have primary neurites that enter the ganglion core as part of an anatomically denned bundle and have cell bodies that lie near each other in the ganglion cortex (Siegler and Pousman, J Comp Neurol: 297:298, 1990). The morphology of the neuropilar branches of the motor neurons is correlated with the pairwise topographic arrangement of the target muscles rather than the muscles' functions. Thus, motor neurons that innervate antagonistic pairs of muscles may be more similar in morphology than motor neurons that innervate synergistic muscles. We find no evidence that particular main branches of the different motor neurons are uniquely associated with a particular motor function. Significant differences in the nature and distribution of synaptic inputs to motor neurons of different function would necessarily be expected as a basis for known differences in synaptic connectivity, but may not be apparent at the level of resolution available from light microscope examination.
Ultrastructural changes in the nucleolus of facial motor neurons following axotomy during an early critical period in development
Authors: Clark Pamela , Jones Kathryn J. , La Velle Arthur 
Published: January 2005

AbstractIn this study, the effects of axotomy on the ultrastructure of the nucleolus and associated organelles were examined in fetal, newborn, and early postnatal facial motoneurons of the hamster. Golden hamsters used for this study were the 14‐day fetus, newborn (0 days; < 6 hr) and 2, 4, 7, and 9 days postnatal ages, with 3 animals per group. For prenatal surgeries, pregnant hamsters were anesthetized and the facial nerves severed in the fetuses via electrocautery through the uterine wall and amniotic membrane. For postnatal surgeries, the animals were anesthetized and the right facial nerve exposed and severed at its exit from the stylomastoid foramen. At the appropriate postoperative times, the animals were reanesthetized and perfused‐fixed. The facial nuclear groups were dissected and processed for routine electron microscopy. Microbody and coiled body frequencies were determined from the number of neurons containing these structures per number of neurons sampled per animal in each experimental or control group and subjected to statistical analysis. Nucleolar reactive changes that occurred during this developmental sequence fell into two major categories. The first category displayed by most injured cells consisted of an initial compacting of fibrillar material and reduction in vacuolar space. The second category appeared to represent a progression from this first stage of nucleolar reactivity into degenerative changes involving a striking segregation of nucleolar components into five distinct regions. The incidence of microbodies increased as a result of axotomy, whereas the presence of coiled bodies decreased at the later postoperative stages in the older animals. With increasing age and nucleolar maturation, the nucleolar reactive pattern became less pronounced and severe, and neuronal survival predominated. It appears, therefore, that the two categories of nucleolar changes following axotomy during early development correlate with changes observed in nucleoli under conditions of rRNA downregulation. It is hypothesized from these results that a key step in the ability of neurons to survive axotomy and successfully regenerate at these early developmental stages occurs at some point in ribosomal RNA transcription and/or processing. Complementary information at the molecular level concerning changes in nucleolar synthetic activity and ribosome production will be necessary to test this hypothesis.
Intraorbital transection of the rabbit optic nerve: Consequences for ganglion cells and neuroglia in the retina
Authors: Scherer Jürgen , Schnitzer Jutta 
Published: January 2005

AbstractRabbit retinae were stained with antibodies to glial fibrillary acidic protein (GFAP) at various times up to 5 months after complete unilateral intraorbital optic nerve transection, which is known to induce degeneration of ganglion cell axons and perikarya in the retina. A transient immunoreactivity for GFAP was observed in Müller glial cells that normally lack this marker. Müller‐cell GFAP immunoreactivity became detectable 4 days after the lesion, but Müller cells were no longer labeled 3 months later. GFAP‐labeled astrocytes located in the nerve fiber layer showed no change in immunoreactivity at any stage after transection.Application of horseradish peroxidase to the left and right superior colliculus of a rabbit whose optic nerve had been transected unilaterally 2 years before confirmed the completeness of the transection. Yet electron microscopy showed the presence of some healthy‐looking ganglion cell axons in the lesioned retina, although these cells were deprived of their target.Labeling retinal wholemounts with neurofilament antibodies confirmed the presence of some ganglion cell axons and perikarya in the retina more than 2 years after transection. The course of these axons suggested that they were remnants of axons. Using antibodies to galactocerebroside (GC) we found that, as in the normal rabbit, these persisting ganglion cell axons were myelinated in the medullary rays. Although many ganglion cell axons had disappeared after 2 years, the number of neuroglial cells (including astrocytes and oligodendrocytes) present in the medullary ray region was not altered. The cell bodies of some oligodendrocytes were covered with a myelin sheath, an aberrant feature not seen normally.
Cross‐species septohippocampal transplants: Ultrastructure of Thy‐1.2‐labeled donor fibers into the dentate gyrus
Authors: Wells Joseph , Vietje Brad P. , McKeon Robert J. 
Published: January 2005

AbstractA naturally occurring species‐specific membrane marker was used to identify unambiguously transplanted septal cells and their fibers which have grown into host tissue. Cell suspensions of the septum/basal forebrain region of C57B1/6 mouse embryos were transplanted into the dentate gyrus of Sprague‐Dawley rats that had received a fornix lesion. The membranes of the mouse contained Thy‐1.2, while the membranes of the rat contained Thy‐1.1. An antibody to Thy‐1.2 clearly identified the donor tissue and did not react with the Thy‐1.1 of the host's membranes. The ultrastructure of the immunoreactively labeled tissue confirmed previous biochemical findings on the distribution of Thy‐1 and showed Thy‐1.2 immunoreactivity on axons and dendrites, microtubules, some mitochondrial membranes, and the surface membranes of cell bodies. Within the transplant, a few glial profiles showed immunoreactive fibrils, but most glial profiles within the transplant and all glial profiles outside the transplant were not immunoreactive. Astrocyte fibers enclosed the outgrowing labeled fibers to form fascicles, but did not penetrate the fascicle. There was no other distinctive association of astrocytic profiles with immunoreactive fibers. Dendrites grew for long distances into the host's molecular layer. Many immunoreactive dendritic profiles formed synapses with unlabeled terminal profiles from the host. The host synapses on the long dendrites of the transplanted neurons may form an important source of input for the initiation of physiological activity in the new circuits established by the transplant. A few labeled (donor) synaptic terminals were observed in the molecular layer, but Thy‐1.2‐labeled dendritic profiles were much more prominent than labeled axonal profiles.