bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antibodies against retinal photoreceptor‐specific proteins reveal axonal projections from the photosensory pineal organ in teleosts
Authors: Ekström Peter , Foster Russell G. , Korf Horst‐W. , Schalken John J. 
Published: January 2005

AbstractWith the aid of specific antisera to the retinal proteins S‐antigen and α‐transducin and to the rhodopsin apoprotein opsin, we have labeled various cell populations in the pineal organ, parapineal organ, habenular nucleus, and subcommissural organ in two teleost species: the rainbow trout and the European minnow. Although these proteins are associated with photoreceptor functions, not only photoreceptor cells but also the majority of parenchymal cells in the pineal organ were immunoreactive. Immunoreactive cells with dendrite‐ and axonlike processes were observed also in the parapineal organ and the habenular nucleus. Furthermore, S‐antigen‐immunoreactive, long, axonal processes were observed in the pineal organ and could be traced from the pineal organ to the habenular nucleus and to the pretectal area. In the light of recent HRP electron microscopical and immunocytochemical studies we propose (1) that not only the classical pineal photoreceptor cells of poikilothermic vertebrates but also other types of CSF‐contacting neurons may be the phylogenetic ancestors of mammalian pinealocytes, and (2) a close interrelationship between the pineal organ and the limbic system, effectuated by the direct projections from pineal photoreceptors/CSF‐contacting neurons/pinealocytes to the habenular nucleus, and by displaced “pinealocytelike” elements scattered in the habenular nucleus.
Plantar motoneuron columns in the rat
Authors: Crockett David P. , Harris Suzan L. , Egger M. David 
Published: January 2005

AbstractIn the rat, the numbers and locations of motoneurons innervating the short plantar muscles of the hindlimb (supplied by the medial and lateral plantar nerves, as well as a branch of the sural nerve) were determined by using both horseradish peroxidase (HRP) and fluorochromes as retrograde labels.Topographical organization within the plantar motor nucleus was examined by exposing individually the cut ends (encapsulated in low melting‐point paraffin) of medial plantar, lateral plantar, and sural nerves to HRP. In addition, double‐labeling experiments were conducted in which the medial plantar nerve was labeled with one fluorochrome (either true blue or diamidino yellow) and the lateral plantar nerve with another.The plantar motor pool is located in the extreme dorsolateral portion of the ventral horn, usually concentrated in the fifth lumbar (L5) spinal segment. Labeled motoneurons extended caudally into the sixth lumbar (L6) segment and rostrally into portions of the fourth lumbar (L4) segment. Motoneurons of the medial plantar, lateral plantar, and sural nerve have overlapping territories. Sural motoneurons (about 70 cells per side) are generally confined to L5, medial plantar motoneurons (about 180 cells per side) tend to be concentrated in caudal L5 and rostral L6, whereas the lateral plantar motoneurons (about 310 cells per side) extend throughout the entire length of the plantar motor pool.The distribution of motoneuronal cell size is unimodal (mean cross‐sectional area = 610 ± 150 μm2). Cell bodies of plantar motoneurons tend to have similar geometries in all three major planes of sectioning.In all, the combined plantar plus sural nerve population amounts to about 560 motoneurons on each side of the spinal cord. On the basis of these data, and those published by others, the innervation of the small muscles of the foot accounts for about 25% of the motor axons carried by the entire sciatic nerve.
Morphology, number, and distribution of putative GABA‐ergic neurons in the basilar pontine gray of the monkey
Authors: Their Peter , Koehler Walther 
Published: January 2005

AbstractWe used an antibody raised against the inhibitory transmitter gamma‐aminobutyric acid (GABA) in the basilar pontine gray (bpg) of the monkey. Somata, dendrites, and a plexus of probably axonal fibers exhibited GABA‐like immunoreactivity. Labeled neurons were small with oval, triangular, or circular soma shape. They gave rise to 2 to 4 dendrites with little branching. No axons were seen issuing from the soma. Occasionally, appendages consisting of spheroidal bodies positioned at the distal end of tenuous stalks and (in 1 cell) axonlike processes were observed to originate from dendrites. According to their morphology, we suggest that these putative GABA‐ergic neurons may correspond to the type II neurons observed in Golgi material.The average number of putative GABA‐ergic cells in 40–μm sections was about 30/mm2. When compared with Nissl‐stained sections, these amounted to about 5% of all cells. There was no substantial variation in average density in different parts of the bpg. However, labeled cells tended to lie in clusters, perhaps related to the well‐established input‐output compartments of the bpg.The demonstration of a significant population of putative inhibitory neurons challenges the traditional view of the bpg, which suggests that this brainstem cell group functions as a simple relay exchanging signals between cortex and cerebellum.
Evidence for coexistence of GABA and dopamine in neurons of the rat olfactory bulb
Authors: Gall Christine M. , Hendry Stewart H. C. , Seroogy Kim B. , Jones Edward G. , Haycock John W. 
Published: January 2005

AbstractImmunoreactivities for γ‐aminobutyric acid (GABA) and the dopaminesynthesizing enzyme tyrosine hydroxylase (TH) wore localized ultrastructurally and colocalized at the light microscopic level in neurons of the rat main olfactory bulb. By means of a simultaneous indirect immunofluorescence technique, GABA and TH immunoreactivities were found to coexist in a large number of neurons in the glomerular and external plexiform layers. Virtually all the TH‐immunoreactive periglomerular neurons also contained GABA immunoreactivity (GABA‐I) while there was an additional number of GABA‐immunoreactive periglomerular cells (27%) which did not contain TH immunoreactivity (TH‐I). In contrast, the numerous tufted‐type neurons in the glomerular and superficial external plexiform layers which contained TH‐I did not contain GABA‐I. In the external plexiform layer (EPL), 41% of the immunoreactive neurons contained GABA‐I alone, 24% contained TH‐I alone, and 35% contained both. EPL neurons containing GABA‐I only or both GABA‐I and TH‐I never exhibited tufted cell morphological characteristics and were generally of the short‐axon type. Electron microscopic examination of GABA‐I and TH‐I elements in the glomerular layer detected morphologically similar periglomerular perikarya and intraglomerular processes immunoreactive for each substance and other neurons and processes of the same type containing neither GABA‐I or TH‐I. These data indicate that the classical neurotransmitters GABA and dopamine coexist in large numbers of neurons in the rat main olfactory bulb including characteristic periglomerular cells and certain other local‐circuit neuronal types.
Enkephalin fibers in autonomic nuclear regions: Intraspinal vs. supraspinal origin
Authors: Romagnano Maryann A. , Braiman Jonathan , Loomis Mario , Hamill Robert W. 
Published: January 2005

AbstractThe present studies in the rat employ spinal transactions and hemisections, dorsal and/or ventral rhizotomies to determine whether enkephalin fibers in spinal sympathetic and parasympathetic nuclei are of supraspinal, intraspinal, or peripheral origin. Our results suggest enkephalin fibers in thoracolumbar sympathetic nuclei are of both supraspinal and intraspinal origin, whereas the enkephalin innervation of the sacral parasympathetic nucleus is primarily intraspinal in origin. Furthermore, the majority of descending enkephalin systems selectivity project to the intermediolateralis, pars principalis and pars funicularis, and the dorsal commissural sympathetic nuclei, whereas intraspinal enkephalin pathways appear to exist primarily in the intercalatus spinalis and intercalatus spinalis, pars paraependymalis sympathetic nuclei. These new observations suggest that specific patterns exist for supraspinal and intraspinal enkephalin pathways.
Ontogeny of peptide‐ and amine‐containing neurones in motor, sensory, and autonomic regions of rat and human spinal cord, dorsal root ganglia, and rat skin
Authors: Marti E. , Gibson S. J. , Polak J. M. , Facer P. , Springall D. R. , van Aswegen G. , Aitchison M. , Koltzenburg M. 
Published: January 2005

AbstractThe developmental patterns of neurofilament triplet proteins, peptide and amine immunoreactivities were compared in motor (ventral spinal cord), sensory (dorsal spinal cord, dorsal root ganglia, epidermis), and autonomic (intermediolateral cell columns, dermis) regions in the rat and human. In the rat, neurofilament triplet proteins first appeared in motoneurones (embryonic day 13). In the youngest human fetuses studied (6 weeks), immunoreactivity was present throughout the spinal cord. Peptides and amines occurred later. Calcitonin gene‐related peptide, galanin, somatostatin, neuropeptide Y and its C‐flanking peptide (CPON) were the first to appear localized to motoneurones (embryonic days 15–17 rat, fetal weeks 6–14 human). Numbers of immunoreactive motoneurones decreased toward birth, but immunoreactive fibers increased in the ventral horn with enkephalin, thyrotrophin‐releasing hormone, and the monoaminergic markers 5‐hydroxytryptamine and tyrosine hydroxylase (all presumably of supraspinal origin) the last to appear perinatally. In the dorsal horn, particularly in the rat, a transient expression of substance P‐, somatostatin‐, and neuropeptide Y/CPON‐immunoreactive cells was detected (embryonic days 15–17). A pronounced increase of calcitonin gene‐related peptide‐, galanin‐, somatostatin‐and substance P‐ immunoreactive fibers was found perinatally in both species. This coincided with an increased detection of cells in the dorsal root ganglia containing these peptides and the earliest appearance of calcitonin gene‐related peptide‐, somatostatin‐, and substance P‐immunoreactive fibers in the rat epidermis. Few antigens were localized to the intermediolateral cell columns before embryonic day 20 (rat), fetal week 20 (human), with thyrotrophin‐releasing hormone‐, 5‐hydroxytryptamine‐, tyrosine hydroxylase‐, and vasoactive intestinal polypeptide‐immunoreactive nerves appearing perinatally. In the rat dermis, tyrosine hydroxylase‐immunoreactive fibers (sympathetic fibers) and fibers immunoreactive for neuropeptide Y/CPON and vasoactive intestinal polypeptide were detected from postnatal day 1. In conclusion, (1) peptide and amine immunoreactivity develops in motor before sensory or autonomic regions, (2) many pep tide‐containing cells are transient in fetal life, and (3) central terminals of dorsal root ganglion cells express peptides before terminals in the skin.
Correlations between structure, topographic arrangement, and spectral sensitivity of sound‐sensitive interneurons in crickets
Authors: Atkins Gordon , Pollack Gerald S. 
Published: January 2005

AbstractThe morphology of nine prothoracic, sound‐activated, interganglionic interneurons in Teleogryllus oceanicus is described. Only two of the neurons can, on anatomical grounds, receive input directly from auditory receptors. The morphology of many of the cells suggests that they may provide output to motor areas. The nine cells can be divided into two groups on the basis of their spectral sensitivity: high‐frequency neurons and low‐frequency neurons. Correlations were found between morphology and spectral sensitivity. High‐frequency neurons have a ventromedial soma, dorsally positioned neuropile processes, and an axon in the lateral half of the promesothoracic connective. In contrast, low‐frequency neurons have a dorsal and/or laterally positioned soma, neuropile processes in the ventral portion of the prothoracic ganglion, and an axon projecting in the medial half of the connective. These findings reveal the existence of a crude tonotopic organization of central neurons. In addition, they provide hints as to the type of output and the targets of these neurons.
Retina of the tadpole and frog: Delayed dendritic development in a subpopulation of ganglion cells coincident with metamorphosis
Authors: Frank Bennett D. , Hollyfield Joe G. 
Published: January 2005

AbstractIn this study, the morphology of tadpole retinal ganglion cells was compared to that of frogs to determine if changes in dendritic structure occur during metamorphosis. Ganglion cells were analyzed in the tadpole and frog after backfilling with horseradish peroxidase. Representative ganglion cells are present in the tadpole retina, which directly correspond to each of the 7 cell classes found in the frog. However, cells in 3 of these classes (1, 3, and 7) exist in morphologically immature states in retinas from tadpole stages St. XIV‐XIX. New dendritic branches appear and the dendritic arbors of these ganglion cells expand during metamorphosis. We propose that the increased dendritic arborization may be followed by new synaptic contacts onto these cells, which contributes to the emergence of new physiological receptive field properties in the frog.
Rod bipolar array in the cat retina: Pattern of input from rods and GABA‐accumulating amacrine cells
Authors: Freed Michael A. , Smith Robert G. , Sterling Peter 
Published: January 2005

AbstractThe potential and actual connections between rod and rod bipolar arrays in the area centralis of the cat retina were studied by electron microscopy of serial ultrathin sections. In the region studied there were about 378,000 rods/mm2 and 36,000–47,000 rod bipolars/mm2. The tangential spread of rod bipolar dendrites was 11.2 μm in diameter, and the “coverage factor” for the rod bipolar cell was 3.5–4.6. We estimate that about 37 rods potentially converge on a rod bipolar cell and that one rod potentially diverges to about four rod bipolar cells. The actual connections, however, are less than this by about half: 16–20 rods actually converge on a bipolar cell and one rod actually diverges to slightly less than two rod bipolar cells. The degree of convergence appears to reflect a compromise between the need to signal graded stimulus intensities (requiring wide convergence) and the need to maintain a good signal/noise ratio (requiring narrow convergence).Amacrine varicosities that provide reciprocal contact at the rod bipolar dyad were studied in serial electron microscopic autoradiograms following intraocular administration of 3H‐GABA or 3H‐glycine. More that 90% of the reciprocal amacrine processes accumulated GABA in a specific fashion. This information, in conjunction with Nelson's recordings from the rod bipolar and amacrine cells postsynaptic at the dyad (Nelson et al: Invest. Ophthalmol 15:9 46–953, '76; Kolb and Nelson: Vision Res. 23:301–312, '83), suggests that feedback at the rod bipolar output might be positive.
Ultrastructural organization of normal and transplanted rat fascia dentata: I. A qualitative analysis of intracerebral and intraocular grafts
Authors: Sørensen Torben , Zimmer Jens 
Published: January 2005

AbstractFew studies have dealt with the general ultrastructure and synaptic organization of grafted brain tissue. This study was therefore performed to extend current light microscopic observations on intracerebral and intraocular grafts of hippocampal tissue to the ultrastructural level. Blocks of tissue containing the hippocampus and fascia dentata from day 21 embryonic rats were grafted into the brain of developing and adult rats and to the anterior eye chamber of adult rats. After 100 or 200 days of survival the recipient rat brains or eyes were processed for electron microscopy. Tissue containing the graft dentate molecular layer and adjacent granule cell layer was selected for ultrastructural analysis, together with a few samples of the hilus and CA3. Normal dentate tissue was analyzed as control.At the light microscopic level most intracerebral and intraocular grafts displayed an organotypic organization with clearly recognizable cell and neuropil layers. Under the electron microscope the grafted granule cells had normal‐appearing dendrites bearing the normal types of spines and forming the normal types of synapses. This was the case even in the absence of the normal major extrinsic afferents like the perforant path. The graft dentate granule cells formed axons and terminals with characteristics of the normal mossy fiber system in the hilus and CA3, in addition to aberrant supragranular mossy fiber terminals known from light microscopic studies of dentate transplants. Abnormal structures included a few dendritic growth cones and an increased occurrence of polyribosomes in spines. Their occurrence indicates ongoing dendritic plasticity even 100 days after transplantation. There was also an increased density of glial elements, particularly in the intraocular grafts. In some of these grafts the granule cells displayed immature traits in terms of nuclear indentations. Dentate interneurons of the basket cell type were present in both the intracerebral and the intraocular grafts.We conclude that grafted dentate granule cells, in different surroundings and without the normal, major perforant path input, can develop a basically normal cellular morphology, which includes the normal ultrastructural characteristics of the dendrites with spines and synapses, and the mossy fibers and its terminals.
Ultrastructural organization of normal and transplanted rat fascia dentata: II. A quantitative analysis of the synaptic organization of intracerebral and intraocular grafts
Authors: Sørensen Torben , Zimmer Jens 
Published: January 2005

AbstractAs part of an ultrastructural analysis of the normal rat fascia dentata and intracerebral and intraocular dentate transplants the synapses in the dentate molecular layer were quantified. Hippocampal and dentate tissue from 21‐day‐old rat embryos were grafted into the brain of developing and adult rats and to the anterior eye chamber of adult rats. After 100 or 200 days of survival the recipient rat brains and the recipient eyes were processed for electron microscopy, and the graft dentate molecular layer with the adjacent granule cell layer selected for ultrastructural analysis. Tissue from the dentate molecular layer of normal adult rats served as control. The dentate synapses were classified as asymmetric (Gray's type 1) or symmetric (Gray's type 2), and according to the postsynaptic element (cell body, dendritic shaft, dendritic spine). The spine synapses were further classified into simple and complex types according to the spine‐terminal configuration. Also, the length of synaptic contacts of the individual synaptic types was measured in some grafts, just as the percentage of the cross sectional area of the neuropil covered by blood vessels.The results showed that the synaptic density, expressed as number per unit area of neuropil, to a large extent was the same within the different parts of the normal dentate molecular layer. Compared with this the synaptic density was reduced with 16.4% in dentate molecular layer of the intracerebral graft, primarily because of a 17.6% reduction of simple synapses on dendritic spines and almost halving of the symmetric synapses on dendritic shafts. The synaptic density was independent of the age of the recipient, the intracerebral location of the graft, and the survival time. Although the synaptic length of some of the individual synaptic types increased, this did not compensate for the loss of synapses. In the intraocular grafts the synaptic density was lower than in the intracerebral grafts.Despite the reduced synaptic density, which mainly involved two synaptic types, we conclude that grafted dentate granule cells can develop a remarkably normal, ultrastructural synaptic organization even in the absence of major afferent inputs. This outcome must accordingly be achieved by reorganization of the available intrinsic afferents.
Raphe nucleus of the pons containing omnipause neurons of the oculomotor system in the monkey, and Its homologue in man
Authors: Büttner‐Ennever J. A. , Cohen B. , Pause M. , Fries W. 
Published: January 2005

AbstractOmnipause neurons take part in the generation of saccadic eye movements. They lie around the midline in the caudal pontine reticulur formation, in an area usually ascribed to the nucleus raphe pontis (rp). In this study of the monkey (Macaca fascicularis and M. mulatta), we describe four series of experiments aimed at establishing that omnipause neurons lie within a distinctive cytoarchitectonic entity, which we call the nucleus raphe interpositus (rip): (1) cytoarchitectural study, (2) recording‐lesion experiments to establish in which cell group omnipause neurons lie, (3) cytochrome oxidase distribution in the omnipause region and neighboring structures, and (4) neuroanatomical tracing experiments to demonstrate afferents to the omnipause region.In the detailed cytoarchitectural study of the midline structures in the caudal pons and rostral medulla, a distinctive group of neurons (rip) adjoining the ventrocaudal border of rp and dorsal to the nucleus raphe magnus (rm) is described. The striking features of rip are the uniformly arranged, narrow row of the cells either side of the midline, and the extensive horizontally oriented dendritic trees of its neurons. The abducens rootlets (NVI) pass through the reticular formation at the same rostrocaudal level as rip and form a reliable landmark for its location. Cytochrome‐oxidase‐stained sections demonstrated additional differences between rip and adjacent cell groups: in rip the neurons and their extensive dendrites stained strongly, but not the surrounding neuropile, whereas in rp both the neurons and the neuropile stained darkly, so that individual neurons were difficult to see.Unlike rp, rip coincides with the location of omnipause neurons, and lesions marking the sites of individual omnipause units lay within its boundaries. Tritiated leucine was injected into superior colliculus (sc), which is known to have monosynaptic connections with omnipause neurons. Labelled axons and patterns of silver grains taken to indicate the presence of terminal branching were found in and around rip, but no significant labelling was seen in rp or rm. It is concluded that the omnipause neurons lie within the rip in the monkey.These functional and morphological differences between rip and the adjacent raphe nuclei are used to justify its characterization as an independent cell group in the monkey.In order to relate these findings to man, cytochrome oxidase experiments were carried out to the human brainstem, and the pattern of staining at the level of the abducens rootlets was correlated with the cytoarchitecture. Similar results to those in the monkey were found, and a group of cells is outlined which we suggest is the homologue of rip in man.