bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell body response to injury in motoneurons and primary sensory neurons of a mutant mouse, ola (Wld), in which wallerian degeneration is delayed
Authors: Bisby M. A. , Tetzlaff W. , Brown M. C. 
Published: January 2005

AbstractWe examined the response to axon injury in the facial motoneurons and dorsal root ganglion (DRG) neurons of C57BL/Ola (Wld) mice, compared with the responses of C57BL/6J mice. The peripheral nerves of Ola mutants undergo remarkably slowed and muted Wallerian degeneration after injury. The increase in GAP‐43 mRNA levels in facial motoneurons and DRG neurons was similar in both strains of mice, as was the initial decrease in medium‐weight neurofilament (NFM) mRNA in facial motoneurons, and the increase in JUN immunoreactivity in both types of neurons. However, the subsequent recovery to normal low levels of JUN and GAP‐43 mRNA expression and high levels of NFM mRNA was delayed in Ola motoneurons. We ascribe this delay to the slow regeneration and target reinnervation of facial axons in the Ola mice.These results show that absence of rapid Wallerian degeneration does not affect the initial cell body response to axonal injury. They also provide further evidence that restoration of normal levels of expression of GAP‐43 and NFM mRNAs is dependent on target reinnervation and/or trophic factors provided by the distal nerve, Impaired regeneration in the Ola mouse does not seem to be a consequence of a defective cell body response to injury, and our results illustrate the general principle that, even if there is a vigorous cell body response to injury, normal axonal regeneration requires the additional provision of a favorable environment for growth. © 1995 Wiley‐Liss, Inc.
Differential regenerative response of purkinje cell and inferior olivary axons confronted with embryonic grafts: Environmental cues versus intrinsic neuronal determinants
Authors: Rossi Ferdinando , Jankovski Aleksandar , Sotelo Constantino 
Published: January 2005

AbstractRegeneration of severed central axons is supposed to depend on two factors: a permissive local environment and the particular intrinsic properties of axotomized neurones. To assess the role of each of these factors in axonal regeneration, the capability of two particular axon populations of the adult mouse cerebellum to grow into target‐specific (cerebellum) and target‐unspecific (neocortex) embryonic grafts was determined. Purkinje cell and inferior olivary axons were transected by passing a microscalpel through the axial white matter of the cerebellar folia, particularly, those of the anterior lobe. Immediately after the injury, solid transplants were placed in the lesion cavity. Purkinje cell axons were labelled by using anticalbindin immunocytochemistry, and olivocerebellar fibres were visualized by biotinylated dextran amine anterograde axonal tracing.Following axotomy, Purkinje cell axons appeared as thickened processes ending with large terminal clubs. Their morphology and number did not change up to the longest survival time considered (2 months), thereby confirming previous demonstrations that Purkinje cells survive axon injury (I. Dusart and C. Sotelo, 1994, J. Comp. Neurol. 347:211–232). Inferior olivary axons were thinner and bore smaller terminal bulbs. When embryonic cerebellar grafts, containing cortical and deep nuclear, precursors, were placed close to the injured axons, olivocerebellar fibres vigorously regenerated into the transplants and ended in new climbing fibies along the dendrites of grafted Purkinje cells. By contrast, host Purkinje cell axons never showed any outgrowth towards the graft. Similarly, these axons failed to regenerate into grafts containing solely the rostromedial portion of the cerebellar anlage, mostly consisting of deep nuclear neurones, their main targets. Comparable results were obtained by transplanting embryonic neocortical tissue: inferior olivary axons also regenerated into the grafts, although with distinct terminal arbours without the climbing fibre phenotype, whereas Purkinje cell axons always failed to grow.These results provide the first direct demonstration that severed inferior olivary axons are able to regenerate. In addition, they show that the growth‐permissive/‐promoting conditions created by embryonic nervous tissue are not sufficient to induce the regeneration of every axonal type and allow us to hypothesise that successful regenamtion depends on the mterplay between environmental cues and intrinsic properties of the axotornized neurones. © 1995 Wiley‐Liss, Inc.
Reorganization of central terminals of myelinated primary afferents in the rat dorsal horn following peripheral axotomy
Authors: Woolf C. J. , Shortland P. , Reynolds M. , Ridings J. , Doubell T. , Coggeshall R. E. 
Published: January 2005

AbstractWe have investigated the time course and extent to which peripheral nerve lesions cause a morphological reorganization of the central terminals of choleragenoid‐horseradish peroxidase (B‐HRP)‐labelled primary afferent fibers in the mammalian dorsal horn. Choleragenoid horseradish peroxidase is retrogradely transported by myelinated (A) sensory axons to laminae I, III, IV and V of the normal dorsal horn of the spinal cord, leaving lamina II unlabelled. We previously showed that peripheral axotomy results in the sprouting of numerous B‐HRP labelled large myelinated sensory axons into lamina II. We show here that this spread of B‐HRP‐labelled axons into lamina II is detectable at 1 week, maximal by 2 weeks and persists for over 6 months postlesion. By 9 months, however, B‐HRP fibers no longer appear in lamina II. The sprouting into lamina II occurs whether regeneration is allowed (crush) or prevented (section with ligation), and does not reverse at times when peripheral fibers reinnervate the periphery. We also show that 15 times more synaptic terminals in lamina II are labelled by B‐HRP 2 weeks after axotomy than in the normal. We interpret this as indicating that the sprouting fibers are making synaptic contacts with postsynaptic targets. This implies that A‐fiber terminal reorganization is a prominent and long‐lasting but not permanent feature of peripheral axotomy. We also provide evidence that this sprouting is the consequence of a combination of an atrophic loss of central synaptic terminals and the conditioning of the sensory neurons by peripheral axotomy. The sprouting of large sensory fibers into the spinal territory where postsynaptic targets usually receive only small afferent fiber input may bear on the intractable touch‐evoked pain that can follow nerve injury. © 1995 Wiley‐Liss, Inc.
Dendritic morphology of CA1 pyramidal neurones from the rat hippocampus: II. Spine distributions
Authors: Bannister N. J. , Larkman A. U. 
Published: January 2005

AbstractThe numbers and distributions of dendritic spines were estimated for six adult and three juvenile biocytin‐injected neurones from the CA1 region of the hippocampus of the albino rat. For each cell, a sample of long dendritic segments that lay favourably in the plane of focus was drawn at high magnification and the visible spines counted. Correction was made for spines obscured by dendritic shafts. Within individual cells, dendrites of similar type and diameter had similar spine densities. For adults, long basal segments averaged 2.4 spines/μm and obliques averaged 3.2 spines/μm. In juveniles, basals averaged 2.3 spines/μm and obliques, 2.5 spines/μm. Apical tuft segments were less spiny, averaging 1.4 spines/μm in adult cells and 1.8 spines/μm in juveniles. There was a positive correlation between spine density and dendrite diameter.Values from this sample were used to assign spine densities to the other segments, and so the total number of spines was estimated for each cell. Adult cells averaged 30,500 ± 3,900 (S. D.) spines and juveniles, 23,800 ± 7,100 spines. Adult cells had roughly 50% of their spines in stratum radiatum, 40% in s. oriens, and 10% in s. lacunosum‐moleculare. Juvenile cells had a rather higher proportion (20%) in s. lacunosum‐moleculare. In general, some 50% of all spines were located within a path length of 200 μm from the soma. These total numbers of spines were much higher than earlier values from Golgi‐impregnated cells but align well with estimates of the numbers of axonal boutons supplied to CA1 by CA3 pyramidal cells. © 1995 Wiley‐Liss, Inc.
A population of wide‐field bipolar cells in the rabbit's retina
Authors: Jeon Chang‐Jin , Masland Richard H. 
Published: January 2005

AbstractWe have stained an unusual population of retinal bipolar cells. When the low molecular weight tracer biocytin was injected into the vitreous body of rabbits, it subsequently accumulated in the somata and processes of a population of wide‐field bipolar cells. The cells have 2–4 primary dendrites. Their dendritic arbors span a field 50 to 200 μm in diameter. The axonal arbors are sparse and often highly asymmetric. The longest dimension of the axonal arbor ranges from 100 to 300 μm. The cells are moderately evenly spaced. They make up less than 1% of the total population of bipolar cells in the rabbit retina.With the whole population stained, regularities in the spatial arrangement of nearby cells can be recognized. Their dendrites often run to a common point, where they have the appearance of making contact with each other. A similar arrangement is seen for the cells' axonal arbors, so that the whole population is spatially linked in both the outer retina and the inner. The exact nature of the points of conjunction cannot be learned from light microscopy. One possibility is that the processes run together because they contact a common target. If so, the target structures (one in the outer retina and one in the inner) must be sparse. An alternative is that the points of conjunction represent synapses or gap junctions among wide‐field bipolars of this type. © 1995 Wiley‐Liss, Inc.
Ultrastructure and synaptology of the nucleus ambiguus in the rat: The compact formation
Authors: Hopkins David A. 
Published: January 2005

AbstractThe fine structure of the esophagomotor compact formation of the nucleus ambiguus was studied. Esophageal motoneurons are atypical in that they have extensive direct somato somatic and somato‐dendritic appositions without intervening glial processes. A unique feature is the presence of finger‐ and leaf‐like somatic protrusions which partially wrap longitudinally oriented dendrites and occasionally, small groups of dendrites and axons. The neuropil contains many longitudinally oriented, small‐diameter dendrites of relatively uniform size (1.1 ± 0.4 S. D. μm in diameter). Motoneuronal somatic profiles have 0–5 synapses per profile which represents a synaptic density of 10.6 synapses per soma. Axodendritic synapses measure 0.5 × 0.7 μm in the transverse plane and are up to 3.0 μm long in the sagittal plane. Many axon terminals contact both a soma and dendrite in close apposition. Most axon terminals (>90%) contain round vesicles and form asymmetric junctions with somata and dendrites. Axon terminal degeneration after electrolytic lesions and labelling after injections of wheat germ agglutinin‐horseradish peroxidase in the nucleus of the tractus solitarius show that afferent connections to the compact formation form axodendritic synapses.The ultrastructure and synaptology of esophageal motoneurons is characterized by the close apposition of somata and dendrites (somatic‐dendritic bundling), and the longitudinal orientation of dendrites (dendritic bundling), axons and axon terminals in the neuropil. These features may be important morphological substrates for synchronization and coordination of esophageal motoneuronal activity and esophageal peristalsis. © 1995 Wiley‐Liss, Inc.
Vasopressin and galanin mRNAs coexist in the nucleus of the horizontal diagonal band: A novel site of vasopressin gene expression
Authors: Planas Barbara , Kolb Pamella E. , Raskind Murray A. , Miller Margaret A. 
Published: January 2005

AbstractVasopressin (VP) neurons have been identified in several brain regions where VP has been hypothesized to act as a neurotransmitter or neuromodulator. In many sites, VP is colocalized with the neuropeptide galanin (GAL). Here, using single in situ hybridization histochemistry, we have identified a novel group of neurons within the nucleus of the horizontal diagonal band of Broca (HDB) that express the VP gene and have assessed the distribution of these cells in adult male and female rats (90 days old, n = 7/group). VP mRNA‐expressing neurons were scattered throughout the rostrocaudal extent of the HDB, and the number of VP neurons detected unilaterally ranged from 1 to 17 cells per 20 μm section. Using double in situ hybridization histochemistry on alternate sections, we have assessed the number of cells expressing VP and/or GAL mRNAin the diagonal band and have determined the extent of their colocalization. Approximately 50% of all VP‐expressing neurons in the HDB coexpressed GAL mRNA, and 33% of GAL‐expressing neurons in this region coexpressed VP mRNA. No sex differences were detected in the number of neurons expressing either VP or GAL mRNA or in the incidence of coexpression of VP and GAL mRNAs in this region. VP neurons in the HDB exhibited a low level of expression, and cellular VP mRNA content did not differ between male and female rats. However, sex differences were present in the bed nucleus of the stria terminalis (BNST) of these same rats. Consistent with our previous findings, both the number of VP‐expressing neurons (P ≤ 0.0004) and the cellular VP mRNA content (P ≤ 0.02) in the BNST were greater in male than in female rats. These results suggest that VP gene expression is differentially regulated by gonadal hormones in the HDB compared to the BNST. Because GAL was previously reported to colocalize with acetyicholine (ACh) and gonadotropin‐releasing hormone (GnRH) in the diagonal band of Broca, our findings suggest that VP may also colocalize with these transmitters in this brain region. Our observations may provide an anatomical basis for the postulated actions of VP in functions involving ACh or GnRH pathways. © 1995 Wiley‐Liss, Inc.
Effects of neonatal enucleation on the organization of callosal linkages in striate cortex of the rat
Authors: Olavarria Jaime F. , Li Chi‐pei 
Published: January 2005

AbstractLewis and Olavarria ([1995] J. Comp. Neurol. 361:119–137) showed that the mediolateral organization of callosal linkages differs markedly between medial and lateral regions of striate cortex in the rat. Thus, callosal fibers originating from medial regions of striate cortex interconnect loci that are mirror‐symmetric with respect to the midsagittal plane. In contrast, fibers from lateral regions of striate cortex show a reversed pattern of connections: tracer injections into the 17/18a border produce retrograde cell labeling in regions medial to the contralateral 17/18a border, whereas injections placed somewhat medial to the 17/18a border label cells located at the contralateral 17/18a border.Based on the interpretation that callosal fibers from lateral striate cortex connect retinotopically corresponding loci (Lewis and Olavarria [1995] J. Comp. Neurol. 361:119–137) we propose here that the development of the reversed pattern of connections in lateral portions of striate cortex is guided by activity‐dependert cues originating from spontaneously active ganglion cells in temporal retina. In the present study we have attempted to falsify this hypothesis by investigating the effects of neonatal bilateral enucleation on the organization of callosal linkages in striate cortex of the rat.Once enucleated rats reached adulthood, we studied the mediolateral organization of callosal connections by placing small injections of different fluorescent tracers into different loci within medial and lateral striate cortex. The analysis of the distribution of retrogradely labeledcallosal cells indicated that connections from lateral portions of striate cortex were no longer organized in a reversed fashion, rather, they resembled the mirror image pattern normally found in the medial callosal region, i. e., injections at the 17/18a border produced labeled cells at the opposite 17/18a border, whereas injections into slightly more medial regions produced labeled cells in the opposite, mirror‐symmetric location. In addition, we found that enucleation does not alter the organization of callosal linkages in medial portions of striate cortex.Thus, by showing that enucleation significantly changes the pattern of connections from lateral portions of striate cortex, the present study does not falsify, but rather strengthens the hypothesis that interhemispheric correlated activity driven from the temporal retinal crescent guides the normal development of reversed callosal linkages in lateral portions of rat striate cortex. Furthermore, the present study shows that, in the absence of the eyes, the pattern of callosal linkages in lateral portions of striate cortex resembles the mirror image pattern normally found only in medial striate cortex. © 1995 Wiley‐Liss, Inc.
Distribution of non‐NMDA glutamate receptor mRNAs in the developing rat cochlea
Authors: Luo Lin , Brumm Duane , Ryan Allen F. 
Published: January 2005

AbstractIn situ hybridization was used to document the distribution of mRNA encoding six subunit isoforms of non‐N‐methyl D‐aspartic acid (NMDA) glutamate receptors (GluR1, GluR2, GluR3, GluR4, GluR5 and GluR6) in the inner ears of embryonic, postnatal and adult rats. GluR2 and GluR3 expression in the spiral ganglion appeared well before birth, and reached adult levels several days before the onset of function in the cochlea. In the spiral limbus, expression of GluR2 and GluR3 mRNA reached very high levels at around the time of birth, then declined after a few days. Low levels of GluR1, GluR4 and GluR6 expression were detected in various tissues of the cochlea during development. In the adult cochlea, GluR expression was limited to GluR2 and GluR3 mRNAs in the spiral ganglion neurons and GluR2 mRNA in fibrocytes of the spiral limbus, a non‐neural tissue. The ontogenetic expression of additional GluR subunit genes and their appearance in different cochlear tissues could reflect different roles for these genes during development, or less precise regulation of gene expression within the GluR family. In particular, the very high levels of GluR gene expression in the spiral limbus during the perinatal period support a non‐neural function, perhaps as cell surface receptors during tissue differentiation. © 1995 Wiley‐Liss, Inc.
Glutamatergic and GABAergic input to rat spinothalamic tract cells in the superficial dorsal horn
Authors: Lekan Helena A. , Carlton Susan M. 
Published: January 2005

AbstractThe distribution of synaptic terminals onto spinothalamic tract cells (types I and II) of the superficial dorsal horn was determined with special reference to the amino acid transmitters glutamate and γ‐aminobutyric acid. Fifteen spinothalamic cells retrogradely labeled from the thalamus with the neuroanatomical tracer wheatgerm agglutinin conjugated to horseradish peroxidase were sectioned for electron microscopy. Serial sections from several levels through each cell were immunostained for glutamate and γ‐aminobutyric acid using a postembedding immunogold technique. Perimeter measurements of spinothalamic cell somata and dendrites and the lengths of apposition for all terminal profiles in contact with the spinothalamic cells were obtained from electron micrographs using a digitizing tablet. These data were used to determine the density of terminals on the soma and dendrites. In addition, the terminal population on these cells was categorized by transmitter content (glutamate, γ‐aminobutyric acid, or unlabeled). The results demonstrate that terminal density increased on dendrites relative to their distance from the soma. Glutamatergic and GABAergic input composed 37% and 20% of the terminal population, respectively, and these percentages remained uniform for the soma and dendrites. There were no significant differences among the 15 cells analyzed for this study. The results, therefore, suggest that both type I and type II STT cells of the superficial DH have similar synaptic organizations. © 1995 Wiley‐Liss, Inc.
“Satellite cells” and nerve terminals in the crayfish opener muscle visualized with fluorescent dyes
Authors: Harrington C. C. , Atwood H. L. 
Published: January 2005

AbstractNerve terminals and associated cells on the muscle's surface were visualized in the crayfish opener muscle with several fluorescent dyes in conjunction with confocal microscopy and conventional fluorescence microscopy. The nerve terminals of the excitatory and inhibitory axons were best seen with 4‐diethylaminostyryl‐N‐methylpyridinium iodide (4‐Di‐2‐Asp). This dye is selectively accumulated in mitochondria, which are numerous both in the axons and in synapse‐bearing terminal varicosities. Muscle nuclei were also clearly visualized, because they excluded 4‐Di‐2‐Asp but were stained by acridine orange (AO). A positive attraction between muscle nuclei and nerve terminals was evident by visual inspection and was confirmed by spatial statistics. Additional flat cells on the muscle's surface appeared as bright rings with elongated processes that were often close to or overlapped nearby nerve terminals. The structure of these cells was established by electron microscopy after labeling them with fluorescent polystyrene beads, which could be found over structures on the muscle surface in sections of embedded specimens. The flat surface cells were distinct from peripheral glial cells closely associated with axons and nerve terminals. Nevertheless, spatial statistics showed that the surface cells were grouped near nerve terminals. They occupied a small fraction of the muscle cell's surface. Their functional role has not been determined in crustacean muscles. © 1995 Wiley‐Liss, Inc.
Immunocytochemical identification of cone bipolar cells in the rat retina
Authors: Euler Thomas , Wässle Heinz 
Published: January 2005

AbstractWe studied the morphology of bipolar cells in fixed vertical tissue sections of the rat retina by injecting the cells with Lucifer Yellow and neurobiotin. In addition to the rod bipolar cell, nine different putative cone bipolar cell types were distinguished according to the position of their somata in the inner nuclear layer and the branching pattern and stratification level of their axon terminals in the inner plexiform layer. Some of these bipolar cell populations were labeled immunocytochemically in vertical and horizontal sections using antibodies against the calcium‐binding protein recoverin, the glutamate transporter GLT‐1, the alpha isoform of the protein kinase C, and the Purkinje cell marker L7. These immunocytochemically labeled cell types were characterized in terms of cell density and distribution.We found that rod bipolar cells and GLT‐1‐positive cone bipolar cells occur at higher densities in a small region located in the upper central retina. This area probably corresponds to the central area, which is the region of highest ganglion cell density. A second peak of rod bipolar cell density in the lower temporal periphery matches the retinal area of binocular overlap. The population densities of the immunocytochemically characterized bipolar cells indicate that at least 50% of all bipolar cells are cone bipolar cells. The variety and total number of cone bipolar cells is surprising because the retina of the rat contains 99% rods. Our findings suggest that cone bipolar cells may play a more important role in the visual system of the rat than previously thought. © 1995 Wiley‐Liss, Inc.