bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glycine uptake by lamprey spinal neurons demonstrated by light microscopic autoradiography
Authors: Sheridan Philip H. , Youngs Laurie J. , Krieger Neil R. , Selzer Michael E. 
Published: May 2005

AbstractWe have mapped the neuronal uptake of 3H‐glycine in the spinal cords of large larval sea lampreys: Petromyzon marinus. Spinal cords were incubated in 10−6 M 3H‐glycine for 15 minutes. They were rinsed in lamprey solution, fixed in phosphate‐buffered 2% glutaraldehyde, and washed in phosphate buffer. They were then sectioned with a cryostat at 16‐m thickness or dehydrated, embedded in Epon, and sectioned at 1–4 μm. Sections were coated with a photographic emulsion and maintained at 4°C for 1–7 days.By sectioning horizontally, it was possible to obtain complete serial reconstructions of up to 1.5‐mm lengths of cord in 100–150 sections. The outlines of labelled cells were traced with a Nikon drawing attachment. For one Epon‐embedded spinal cord sectioned at 4 μm, tracings were superimposed to form complete maps for 0.6–1.5‐mm lengths in three representative regions of cord: rostral (gill region), caudal (dorsal fin region), and midsection. The labelled neurons were small (5–10‐μm diameter) cells distributed throughout the central gray columns. They numbered 22 cells per hemisegment in the rostral region, 33 in the midsection, and 43 in the caudal region. None of the previously identified cell types were labelled, including lateral interneurons, edge cells, giant interneurons, dorsal cells, and Müller and Mauthner axons.
Interhemispheric connections of the visual cortex in the grey squirrel (Sciurus carolinensis)
Authors: Gould Harry J. 
Published: May 2005

AbstractThe total pattern of visual callosal connections was studied in the grey squirrel by using the Fink‐Heimer technique for axonal and terminal degeneration and the autoradiographic and horseradish peroxidase techniques for axonal transport. The pattern of terminations was correlated with architectonic landmarks.The results show that callosal terminations are distributed in a complex fashion within the visual cortical areas. The major terminations form a band in area 17 along its border with area 18. This band is contiguous rostrally with the callosal terminations in area L that extend caudomedially onto the medial wall of the hemisphere. Caudally the band in area 17 wraps around the ventral aspect of the occipital pole and ends medially at the level of the hippocampus. This band exhibits a distinct periodicity in the density of terminations. The callosal terminations in area 18 are usually found along the lateral and medial borders and are concentrated in discrete patches. The pattern in area 19 exhibits two or three primary patches and only loosely corresponds to the borders of the area. Few callosal terminations are found in area 19p and the posterior temporal area, Tp, while the intermediate temporal area, Ti, receives an extensive input.The laminar distribution of callosal terminations is different in each area studied. Characteristically, area 18 has dense terminations in layers III, II, and the inner one‐half of layer I, with less dense terminations in layers V and VI, and sparse terminations in layer IV. Area 17 has a similar pattern in the supragranular and infragranular layers but also has dense terminations in layer IV. The patterns in area 19 are intermediate between these extremes but are more similar to those in area 17.The cells that give rise to the callosal projections were found primarily in layers III and V and occasionally in layers II, IV, and VI. The distribution of the callosal efferent neurons is more extensive than the areas of terminations.The distribution of callosal terminations suggests that the organization of visual cortical areas in the grey squirrel is more complex than had been previously recognized. This finding is discussed with reference to the general organization of the mammalian visual cortical areas, and a need for more extensive analyses of visual cortical areas in the grey squirrel, particularly with respect to extrastriate visual areas, is indicated.
Organization of the efferent projections of the nucleus accumbens to pallidal, hypothalamic, and mesencephalic structures: A tracing and immunohistochemical study in the cat
Authors: Groenewegen Henk J. , Russchen Fokje T. 
Published: May 2005

AbstractThe efferent connections of the nucleus accumbens in the cat were studied with the aid of anterograde and retrograde tracing techniques. The description of the topography of these projections to pallidal, hypothalamic, and mesencephalic areas is preceded by a redefinition of the borders of the pallidal regions in the cat, using immunohistochemical criteria. In agreement with previous studies in rat and monkey substance‐P‐like and enkephalinlike immunoreactivity in the pallidum of the cat appears to be present in so‐called “woolly fibers.” Substance‐P‐ and enkephalin‐positive woolly fibers are differentially distributed in the internal and external segments of the globus pallidus, as traditionally defined, but are both present in the rostral part of the substantia innominata, here called the “ventral pallidum.” Woolly fibers are also found in a number of other basal telencephalic structures and in the rostral part of the lateral hypothalamic area.Fibers from the medial part of the nucleus accumbens distribute to the ventral pallidum and to the just‐mentioned area in the rostral part of the lateral hypothalamus, which most probably represents part of the internal segment of the globus pallidus. The medial nucleus accumbens projects in addition to the lateral septum, the bed nucleus of the stria terminalis, the medial preoptic and hypothalamic areas, the ventral tegmental area, the retrorubral nucleus, the central superior nucleus, the nucleus tegmenti pedunculopontinus, and the central gray. The lateral part of the nucleus accumbens projects to the ventral pallidum, the subcommissural part of the globus pallidus, the entopeduncular nucleus, the substantia nigra, and the retrorubral nucleus.
Distribution of enkephalin in human fetus and infant spinal cord: An immunofluorescence study
Authors: Charnay Yves , Paulin Christian , Dray Fernand , Dubois Paul‐Marie 
Published: May 2005

AbstractThe distribution of enkephalin‐like immunoreactivity in the human fetus and infant spinal cord have been studied by indirect immunofluorescence. Enkephalin‐like immunoreactive fibers were detectable in the lateral funiculus of fetal spinal cord as early as 10 weeks. At the other fetal ages examined, ranging from 12 to 28 weeks, and in infant, enkephalinlike immunoreactivity was found widely distributed throughout the whole spinal cord. In fetus spinal cord several enkephalin‐like immunoreactive cells were sometimes seen scattered in the intermediate gray region. Most of the labeling was, however, represented by thin, varicose, immunofluorescent fibers mainly localized in the intermediate gray regions, in the ventral horn and in the superficial dorsal horn layers where they progressively increased in number. Further, the white matter exhibited enkephalin‐like immunoreactive fibers particularly in the lateral funiculus where a dense punctiform immunofluorescence could be seen. On the whole, similar patterns were also visible in infant spinal cord. Thus, the superficial layers of the dorsal horn and the intermediolateral and reticular nuclei areas displayed dense plexuses of immunoreactive fibers. In contrast, the white matter showed only little labeling. In addition, no immunoreactivity was found in fetus and infant dorsal root ganglia. Our results emphasize the wide distribution of the enkephalin‐like immunoreactivity in the fetus as in the infant spinal cord and further suggest its first appearance early in fetal life, possibly at the embryonic stage.
Contralateral, midline, and commissural motoneurons of neck muscles: A retrograde HRP study in the cat
Authors: Abrahams V. C. , Keane J. 
Published: May 2005

AbstractRetrograde transport of HRP has been used to examine the distribution of motoneurons supplying the dorsal neck muscles biventer cervicis, and complexus in the cat. Retrogradely filled cells were present in the expected sites in lamina IX of the ventral horn, but were not confined to that area. Retrogradely labelled cells were also found more dorsally in the ventral horn and in the white matter medial to the ventral horn. Other filled cells were found in the commissural nuclei and in laminae VII and VIII contralateral to the nerve being dipped. Cells in the ipsilateral lamina IX ranged in size from 15 to 70 μm. Cells lying outside this region were smaller with the majority having mean equivalent diameters, of 40 μm or less.
Ultrastructural localization of immunoreactive neurotensin in the monkey superficial dorsal horn
Authors: Difiglia Marian , Aronin Neil , Leeman Susan E. 
Published: May 2005

AbstractNeurotensin, a tridecapeptide, has been proposed to have a role in sensory systems, especially those mediating pain. The light microscopic and ultrastructural localization of neurotensin immunoreactivity in neurons of the monkey spinal cord was studied with the aim of examining their synaptic interactions. At the light microscopic level, neurotensin‐containing cells were located in laminae II and III and immunoreactive axons and terminals were found in laminae I, II, and III. Neurotensin‐positive axons were mostly thin and unmyelinated and their boutons contained both clear and large granular vesicles. Boutons varied considerably in size (1–3μm) and in their relative content of large granular vesicles, which appeared occasionally in presynaptic locations. In lamina I neurotensin‐immunoreactive terminals formed synapses with cell bodies which varied both in size and subcellular features. Some large dendrites in lamina I were contacted by numerous neurotensin‐positive axons and also unlabeled terminals. In lamina II boutons with neurotensin immunoreactivity formed synapses mostly with small unlabeled dendrites some of which contained vesicles.The present results together with recent anatomical and physiological findings suggest that spinal cord neurons which contain neurotensin synapse with cells in the superficial dorsal horn that receive either input from primary afferents conveying nociceptive information or form part of the spinothalamic tract, or both. The diversity observed both in the morphology of neurotensin‐positive terminals and in their synaptic patterns may indicate that they arise from more than one type of dorsal horn cell.
Colonization of the developing murine enteric nervous system and subsequent phenotypic expression by the precursors of peptidergic neurons
Authors: Rothman T. P. , Nilaver G. , Gershon M. D. 
Published: May 2005

AbstractThe development of peptidergic neurons was analyzed in the murine bowel. Neurons, detected immunocytochemically with antisera to substance P (SP) and vasoactive intestinal polypeptide (VIP), respectively, were selected for study. Explantation of the primordial bowel with subsequent growth in organotypic tissue culture served as an assay for the presence of neuronal precursor cells within the developing gut. One objective of the study was to determine whether the neural crest population that initially colonizes the mammalian bowel contains the precursors of peptidergic neurons as well as those of neurons that contain small molecule neurotransmitters, or whether peptidergic neurons are derived from a later migration of émigrés to the gut. A second objective was to compare the timing of peptidergic phenotypic expression with that of the small molecule neurotransmitters, acetylcholine (ACh) and serotonin (5‐HT). The precursors of peptidergic neurons were found to have colonized the bowel prior to the appearance of recognizable neurons of any type. The immunocytochemical detection of SP and VIP in vivo lagged behind the appearance of cholinergic and serotonergic markers by at least 2 days in the foregut and by greater than 3 days in the hindgut. Peptidergic neurons showed a proximodistal pattern of phenotypic expression. These observations support the hypothesis that the murine bowel is colonized by a single wave of precursor cells that contains the primordia of peptidergic neurons as well as neurons that use small molecule neurotransmitters. Data are consistent with the earlier expression of the small molecule phenotype. The proximodistal sequence of phenotypic expression in the absence of a similar sequence in precursor colonization supports an interaction between the precursors of enteric neurons and the microenvironment of the gut that modulates neuronal phenotypic expression.
Observations on the brainstem‐spinal descending systems of normal and reeler mutant mice by the retrograde HRP method
Authors: Terashima Toshio , Inoue Kaoru , Inoue Yoshiro , Mikoshiba Katsuhiko , Tsukada Yasuzo 
Published: May 2005

AbstractBrainstem neurons which project to the lumbar spinal level were identified in both reeler mutant mice and normal controls (Balb/c mice) by the retrograde horseradish peroxidase (HRP) technique. In normal controls after HRP injection into the lumbar cord, retrogradely labelled neurons were observed in (1) the lateral vestibular nucleus, (2) the pontine and medullary reticular formations including the nucleus centralis caudalis pontis, nucleus gigantocellularis, nucleus paragigantocellularis, nucleus raphe magnus et pallidus, and nucleus centralis medullae oblongatae pars ventralis et dorsalis, and (3) the dorsal column nuclei, i.e., the nucleus gracilis and nucleus cuneatus medialis.In reeler mutant mice, labelled neurons were again seen in the nuclei referred to above, and their cellular type and distribution patterns within the corresponding nuclei were similar to those of the normal controls. These observations suggest that (1) the brainstem nuclei of reeler mutant mice which project to the lumbar spinal cord are cytoarchitecturally normal, (2) the reeler genetic locus (rl) does not affect the nonlaminated structures in the brainstem, at least those referred to above, and (3) the motor dysfunctions observed in the reeler, such as action tremor, dystonic posture, and reeling ataxic gait, are not attributable to the brainstem–spinal descending systems.
Morphological alterations in rat CA1 hippocampal pyramidal cell dendrites resulting from chronic ethanol consumption and withdrawal
Authors: McMullen Patricia A. , Saint‐Cyr Jean A. , Carlen Peter L. 
Published: May 2005

AbstractHippocampal CA1 pyramidal cell dendrites were studied in rats after 5 months of consumption of an ethanol liquid diet and 5 months of ethanol diet followed by 2 months of withdrawal. Morphometric data were compared with those obtained from matched littermate, yoke‐fed control animals. Dendritic branching in Golgi–Cox‐stained tissues was assessed by standard and modified Sholl analysis techniques and basilar dendrites were analysed three‐dimensionally by computer.Five months of chronic ethanol consumption caused a significant decrease in the number of second–order basilar dendrites, 60–90 μm from the apical border of the cell layer. No significant changes in the neuronal density of CA1 or CA3 cells were found; however, the thickness of the strata oriens and radiatum of the CA1 field was significantly decreased in the ethanol‐fed group.After 5 months of chronic ethanol consumption and 2 months of withdrawal, the thickness of the strata returned to control sizes and the frequency of proximal basilar branching recovered. Evidence of lengthening and new branching of distal basilar dendrites occurred in the third‐, fourth‐, and fifth‐order segments when control animals 6 and 8 months of age were compared. During the 2–month period of withdrawal, the number and length of third‐, fourth‐, and fifth‐order segments of basilar dendrites increased when compared to the nonwithdrawn ethanol group while the number and length of second‐ and third‐order segments decreased. This is comparable to the changes seen during normal aging and suggests that withdrawal may interact with aging to produce enhanced dendritic growth in “compensation” for the developmental retardation induced by chronic ethanol intake.
Substance P in the interpeduncular nucleus of the rat: Normal distribution and the effects of deafferentation
Authors: Artymyshyn Roman , Murray Marion 
Published: May 2005

AbstractThe interpeduncular nucleus (IPN) is a midbrain structure that receives its major afferents from the medial habenulae via the fasciculi retroflexi. Among the axons projecting to the IPN is a population of substance P (SP)‐containing axons. The IPN has been subdivided into the central, dorsal, intermediate, rostral, and lateral subnuclei using cytoarchitectonic criteria. The distribution of SP among these subnuclei was determined by using Sternberger's ('79) peroxidase‐antiperoxidase technique. In the normal IPN the rostral subnucleus can be subdivided into two sectors on the basis of SP content. The ventral sector contains a moderate amount of SP and scattered SP positive perikarya. The dorsal cap of the rostral subnucleus contains denser SP than the ventral sector and it is continuous with the SP found in the dorsal subnucleus. The lateral subnuclei contain the densest SP found in the IPN and appear as laterally placed columns that expand in size caudally. The central and intermediate subnuclei contain very sparse SP.The fasciculus retroflexus was destroyed in 30 animals unilaterally or bilaterally and animals were perfused 4 days to 3 months postoperatively. After unilateral fascicular lesion, the SP in the rostral part of the ipsilateral lateral subnucleus is almost abolished, but caudally the decrease is confined to its lateral aspect. There is no visible decrease contralateral to the lesion. SP in the rostral part of the cap of the rostral subnucleus is decreased ipsilaterally but no loss is seen contralaterally or caudally. Animals with bilateral lesions show a great decrease in staining in the dorsal cap of the rostral subnucleus and the lateral subnuclei, with no decrease seen in the central, dorsal, or intermediate subnuclei.These results confirm that the origin of most of the SP in the IPN is fasciculus retroflexus fibers, but some of the SP arises from intrinsic SP perikarya located in the ventral sector of the rostral subnucleus and some may also arise from other sources. The areas of the IPN that receive bilateral SP projections from the fasciculus retroflexus (parts of the lateral and rostral subnuclei) show evidence for replacement of SP after lesion. This replacement implies sprouting or an increase in production of SP by remaining systems.
Cytoarchitectonics of substantia nigra grafts: A light and electron microscopic study of immunocytochemically identified dopaminergic neurons and fibrous astrocytes
Authors: Jaeger C. B. 
Published: May 2005

AbstractMaturation of dopaminergic (DA) neurons and astroglia was studied in transplants of the substantia nigra grown for up to 7 months in the brain of rats. The investigation had three specific aims. The first was to observe effects of different transplant positions on the longevity of DA neurons. Second, the grafts were examined for changes of synaptic interactions and associations between DA neurons and astroglia. Third, an answer was sought to the question whether transplanted DA neurons migrate into the adjacent host brain. The grafts were taken from the ventral mesencephalon of rat embryos of different ages (day 14 to 18 of gestation) and placed into the cerebral cortex, tectum, cerebellum, or ventricles of newborn host animals. Following different times of survival the immunocytochemical localization of tyrosine hydroxylase (TH) and of glia filament protein (GFA) in the transplants were observed. In all of the transplantation sites, except for one, neurons of different morphologies that contained TH were found in the grafts. The cerebellar white matter of the host brain failed to support the long‐term survival of DA neurons. The overall structure of mature substantia nigra grafts had some resemblance to intact substantia nigra (SN). On the ultrastructural level, it was found that morphological expression of some immature features of DA neurons, such as glial sheaths, somatic spines, and lack of oligodendroglia, persisted in mature grafts. Specific associations of DA neurons and astroglia in the grafts suggested that the cytoarchitectonic appearance of a given brain region may be related to the existence of particular neuron glia relationships. In contrast to intact SN, transplants revealed deficiencies in unlabeled pleomorphic boutons and contained some TH‐immunoreactive terminals. Migration of DA neurons and their processes into the adjacent host brain was rarely observed.
Subclassification of neurons in the subthalamic nucleus of the lesser bushbaby (Galago senegalensis): A quantitative Golgi study using principal components analysis
Authors: Pearson J. C. , Norris J. R. , Phelps C. H. 
Published: May 2005

AbstractThe morphology of neurons in the subthalamic nucleus (STN) of the lesser bushbaby (Galago senegalensis) is described in coronal brain sections processed by Golgi‐ and Nissl‐staining techniques. Quantitative and statistical methods are used to evaluate (1) soma size and shape, (2) dendritic field size, shape, and branch frequency, (3) the number of dendritic and somatic spines per neuron, and (4) neuron location within the STN. Principal components analysis of these variables suggests that three classes of neurons are present. Two of these classes are considered to be projection cells, referred to as elongate‐fusiform and radiate neurons, respectively. Elongate fusiform neurons have somata and dendritic fields which are large in diameter, extremely fusiform in shape, and give rise to few appendages. Somata and dendritic fields of radiate neurons are smaller in diameter, more rounded in shape, and support more spines than the elongate‐fusiform neurons. The third class of cells in Galago STN is tentatively identified as consisting of interneurons on the basis of small soma and dendritic field size, thin and varicose dendritic morphology, and the presence of multilobulated dendritic appendages.
A comparative study of the intracellular lectin binding sites of neurons in culture with neurons in situ
Authors: Hart Clyde E. , Wood John G. 
Published: May 2005

AbstractThe cytochemical properties of intracellular membrane systems which are likely to be subcellular sites of glycoprotein oligosaccharide synthesis and trafficking have been compared in cultured neuroblastoma cells (as a potential model system) and in Purkinje neurons of rat cerebellum. In aldehyde‐fixed N18 cells, permeabilized with Triton X‐100, concanavalin A (Con A) binding sites were found in the somata, neurites, and growth cones. Con A binding sites in growth cones appeared as a fine, membranous network. Wheat germ agglutinin (WGA) binding sites were restricted to the perinuclear region of the soma and to the distal tips of growing neurites. As shown previously, Purkinje cell somata and presynaptic terminals also contain Con A binding sites. In this study, WGA and succinylated WGA binding sites were observed in the presynaptic terminals of Purkinje cells. Neuraminidase enzyme digestion prior to lectin labeling removed or greatly reduced WGA binding in the neuropil of the deep nucleus but not in presynaptic terminals of Purkinje cells. Succinylated WGA binding sites were not affected by neuraminidase digestion. Neuraminidase digestion also exposed Ricinis communis agglutinin I binding sites in the neuropil and in synaptic terminals of Purkinje cells. These results in combination with previous studies of intracellular lectin cytochemistry of neurons in the central nervous system demonstrate the similarity of these cells to neuroblastoma cells in their intracellular lectin binding characteristics. Results of the lectin cytochemical studies after neuraminidase digestion of presynaptic terminals support the possibility that neurons may use a post‐ or extra‐Golgi system for the addition of peripheral sugars to the oligosaccharides of certain glycoproteins destined for the cell surface.