bluuebunny/crossref_metadata_2025_split huggingface dataset:
The chandelier cell of the human visual cortex: A Golgi study
Authors: Marin‐Padilla Miguel 
Published: January 2005

AbstractThe size, location, distribution, and spatial orientation of the chandelier cell of the human visual cortex are described for the first time. The rapid Golgi method has been utilized to study the structural features of these inhibitory interneurons. The human chandelier cell is a small stellate interneuron with prominent idiodendritic and idioaxonic arborizations. These arborizations are distributed within a narrow rectangular tissue slab that measures approximately 300 × 200 × 100 m̈m. This relatively small and narrow functional territory is oriented perpendicular to the pial surface and to the long axis of the gyrus. The territory of distribution of its axon is larger than and encloses that of its dendrites. The number of specific axonic terminals (candles) per chandelier cell is also relatively small, ranging from 60 to 80 units. These axonic terminals represent the functional units of the neuron and reflect the number of pyramidal cell axons contacted by it. The chandelier cell of the human visual cortex possibly represents the smallest neuron of this kind described to date. The size of its functional territory and the number of its specific axonic terminals are among the smallest of any neuron of this kind thus far described. It is postulated herein that in the course of mammalian phylogeny the chandelier cell shows a tendency toward a progressive reduction in the size of its functional territory and in the number of its functional units (candles), as well as a tendency toward a more “idio” pattern of distribution for its axonic and dendritic arborizations. Perhaps, these progressive evolutionary modifications could reflect a tendency of this type of interneuron toward an increasing specialization. The possible existence of a relationship between the progressive transformation of the chandelier cell and the increasing visual acuity, dexterity, and skillfulness in the course of mammalian phylogeny should be explored.
Morphology of pontomedullary raphe and reticular formation neurons in the brainstem of the cat: An intracellular HRP study
Authors: Edwards D. Louise , Johnston Karen M. , Poletti Charles E. , Foote Warren E. 
Published: January 2005

AbstractIn order to understand better the anatomical substrates underlying processing of sensory information, the cytoarchitecture of neurons in the pontomedullary raphe and reticular formation was investigated following intracellular injections of horseradish peroxidase in the cat. Raphe cells studied were located in the nucleus raphe magnus, nucleus raphe obscurus, and nucleus raphe pallidus. The most prominent type had a smooth, oval cell body and oval dendritic tree with dendrites extending laterally into the adjacent reticular formation. Two other raphe cell types, large cells with a dorsoventral orientation of both cell body and dendritic tree, and very small cells, were rarer. The primary dendritic orientation lay in the coronal plane for all three raphe cell types. Wispy, straight, or clublike spines were located on more distal regions of dendrites, although we also found spineless dendrites. Raphe cells lying near longitudinal fiber pathways exhibited bundling of dendrites around the passing axon fascicles. Reticular formation cells studied were located in the nucleus gigantocellularis, nucleus magnocellularis, nucleus paragigantocellularis dorsalis, and nucleus reticularis paramedianus. Two morphological types were found on the basis of dendritic branching patterns: sparsely branched and densely branched. Most reticular formation cells had round dendritic trees as viewed in the coronal plane and polygonal cell bodies that were medium to large in size. There was no correlation between reticular formation cell morphology and nuclear location. Spines were more common on the densely branched cells, but for both reticular cell types they were usually absent from cell bodies and proximal dendrites. Thus, by using the criteria of dendritic branching and arbor shape along with distance from the midline it was possible to identify raphe cells as distinct from reticular formation cells. In contrast, no morphological characteristics were found that would differentiate cells in the two major median reticular formation nuclei, gigantocellularis and magnocellularis.
Afferent connections of anterior thalamus in rats: Sources and association with muscarinic acetylcholine receptors
Authors: Sikes Robert W. , Vogt Brent A. 
Published: January 2005

AbstractAfferent connections of the anterior thalamic nuclei (ATN) are classically thought to originate in the mammillary body and limbic cortex. This study explores nonlimbic sources of ATN afferents by using retrograde transport of horseradish peroxidase (HUP) to ascertain the relative contribution of these connections. Spread of HRP into adjacent regions was prevented either by removing the overlying cortex or by injecting through permanently implanted cannulas.The main sources of nonlimbic ATN afferents are the pretectum and central gray. Pretectal neurons were HRP‐labeled primarily in the contralateral medial pretectal nucleus with a smaller number in the ipsilateral posterior pretectal nucleus. In the central gray, labeled cells were concentrated ipsilaterally in the laterodorsal tegmental nucleus. Additional projections to ATN originate in the reticular and ventral lateral geniculate nuclei of the thalamus, raphe nuclei, peripontine tegmental nucleus, and locus coeruleus.The association of ATN afferents with muscarinic receptors was also explored by means of in vitro receptor autoradiography with the muscarinic ligands propylbenzilylcholine mustard (PrBCM) and pirenzepine (PZ) in normal rats and rats with ablations. Ibotenic acid injections into ATN were used to destroy intrinsic neurons while leaving afferent fibers intact. Whereas such ablations produced statistically significant decreases in PrBCM binding in the anterior dorsal (AD, −45%) and anterior ventral, magnocellular part (AVm, −51%) nuclei, binding in the anterior ventral, parvicellular part (AVp) and anterior medial (AM) nuclei was not significantly decreased. Furthermore, PZ binding in normal rat ATN was significantly less (−72%) than PrBCM binding. These results suggest that a major proportion of muscarinic binding is associated with presynaptic elements.Ibotenic acid ablations of the mammillary body reduced PrBCM binding in ATN whereas lesions in cingulate cortex and laterodorsal tegmental nucleus had no effect. Compared to sham lesion controls, mammillary body lesions resulted in statistically significant decreases in binding bilaterally in AD (−15%), AVm (−19%), and AM (−20%).In conclusion, ATN receive afferents from several nonlimbic regions. Of these inputs, the pretectum may be the primary route through which sensory information reaches ATN. In addition, cholinergic input may modulate activity in projections from the mammillary body to ATN through presynaptic muscarinic receptors.
Immunohistochemical study on the distribution of neuron‐specific enolase‐ and peptide‐containing nerves in the omasum of cattle
Authors: Kitamura N. , Yamada J. , Yamashita T. 
Published: January 2005

AbstractThe distribution of nerves containing immunoreactivity for substance P (SP), vasoactive intestinal polypeptide (VIP), leucine‐enkephalin (LENK), and gastrin‐releasing polypeptide (GRP) in the margin of the reticulo‐omasal orifice, omasum, and omasal pillar of calves and cows was studied by immunohistochemistry. The general distribution of nerves was determined by means of neuron‐specific enolase (NSE) antiserum and then compared to the distribution of immunoreactive (IR) nerves stained for the four peptides.Marked differences in the distribution of immunoreactive nerves were associated with age and the segment examined. SP‐IR fibers were abundant in the musculature of the ungulate papillae at the reticulo‐omasal orifice and in the smooth muscle of the omasal leaves, moderately dense in the omasal pillar, and low in density in the inner muscle layer of the reticuio‐omasal orifice and in the muscle of the omasal wall. In order of decreasing abundance, the cell bodies of SP‐IR nerves were found at the reticulo‐omasal orifice, in the omasal wall, and in the omasal pillar. LENK‐IR fibers, though less abundant, showed a pattern of distribution that was similar to that of SP‐IR fibers. Nerve cell bodies showing weak immunoreactivity for LENK were detected rarely. Abundant VIP‐IR fibers were present in the inner muscle layer of the reticulo‐omasal orifice and in the omasal wall, while moderate numbers were seen in the omasal pillar: they were low in density in the ungulate papillae and omasal leaves. Cell bodies of VIP‐IR nerves decreased in number through the omasum, reticulo‐omasal orifice, and omasal pillar. The distribution of GRP‐IR nerve fibers was similar to that of VTP‐IR fibers, although GRP‐IR fibers were less abundant. Nerve cell bodies showing weak immunoreactivity for GRP were detected rarely. The individual distribution of peptide‐IR nerves was similar in the calf and cow, but immunoreactive nerves were far more abundant in the calf. The present study provides valuable information for discussion of the possible role of nerves in the regulation of omasal function.
Ultrastructure and distribution of substance P‐immunoreactive sensory collaterals in the guinea pig prevertebral sympathetic ganglia
Authors: Matthews M. R. , Connaughton M. , Cuello A. C. 
Published: January 2005

AbstractA light and electron microscopic study has been made of the substance P‐immunoreactive networks formed by sensory nerve fibres in the prevertebral sympathetic ganglia of the guinea pig to seek confirmation that these networks arise from collateral branches of sensory fibres passing through the ganglia and to explore the synaptic and other specialized relationships established by these networks. Slices from coeliac‐superior mesenteric and inferior mesenteric ganglia of young adult males, perfusion‐fixed by para‐formaldehyde, were immunostained with a monoclonal antibody to substance P, and the immunolabelling was visualized by a peroxidase reaction.Immunolabelled fibres passing through the ganglia were seen by light microscopy to give off varicose collaterals that ramified in the ganglionic neuropil. Electron microscopy showed that the parent fibres were almost exclusively unmyelinated. Many collaterals ran directly beneath the basal lamina bordering the intraganglionic tissue spaces, and the varicosities either remained superficially exposed under the basal lamina or sank deeper into the supporting Schwann cells, becoming apposed to dendrites of the ganglionic neurones, upon which they formed synapses, or to other nerve terminals. The incidence of these specific associations was quantified, singly and in combination. Synapses could be situated at the same level as unlabelled synapses on the same dendrite, and exposed varicosities could lie within 0.5 μm of exposed, postsynaptic dendrites. These observations confirm a collateral, synaptic nature for the networks and suggest additional nonsynaptic modes of release and sites of transmitter action. They are consistent with the hypothesis that the system serves a nocifensor function of axon reflex type.
Ultrastructural identification and localization of climbing fiber terminals in the fastigial nucleus of the cat
Authors: van der Want J. J. L. , Voogd J. 
Published: January 2005

AbstractFollowing injections of 3H‐leucine and 35S‐methionine in the caudal half of the medial accessory olive, labeled climbing fibers were found contralateral to the injection site in the sagittal A‐zone of the cerebellar vermis and in the fastigial nucleus. Labeling in the fastigial nucleus was analyzed with ultrastructural autoradiography. Labeled boutons of climbing fibers were found in the neuropil but never on somata. They contain spherical vesicles and occasionally some dense core vesicles in an electron‐lucent matrix. The terminals of climbing fiber collaterals in the fastigial nucleus resemble climbing fiber terminals in the molecular layer with respect to their internal ultrastructural characteristics.
Localization of aromatase in the brain of the male African catfish, Clarias gariepinus (Burchell), by microdissection and biochemical identification
Authors: Timmers R. J. M. , Lambert J. G. D. , Peute J. , Van Oordt P. G. W. J. , Vullings H. G. B. 
Published: January 2005

AbstractAromatase activity was determined in small discrete areas of the brain of the African catfish, Clarias gariepinus, by a radiometric assay. The fore‐and midbrain were divided into eighteen 500‐μm transverse sections. From these sections several punches (0.3 mg of tissue) were taken and incubated with [19‐3H]‐androstenedione. The aromatase activity, calculated from the release of tritium label during aromatization, is expressed in pmol mg−1 tissue hour−1.The highest activity (3.7 pmol) was detected in the preoptic region. The more caudally located area tuberalis, including the nucleus lateralis tuberis and the nucleus recessus lateralis, also showed a relatively high activity (2.5 pmol).A similar activity was found in the most rostral part of the telencephalon and the dorsal parts of the mesencephalon, i.e., the tectum opticum and torus semicircularis (2.3 pmol). A moderate aromatase activity was observed in remaining parts of the brain, except the cerebellum and hindbrain, in which aromatase activity was hardly detectable (0.1–0.3 pmol).It is concluded that a high aromatase activity is present in regions known to be involved in the regulation of reproduction. Since both the torus semicircularis and the tectum opticum display a high aromatase activity, it is suggested that also these structures are involved in reproductive processes.
Double‐labeling study of axonal branching within the lateral reticulocerebellar projection in the rat
Authors: Ghazi H. , Hrycyshyn A. W. , Flumerfelt B. A. 
Published: January 2005

AbstractCollateral axonal branching to the cerebellum from the lateral reticular nucleus (LRN) was studied in the rat by using the fluorescent double‐labeling technique. Following injection of Fast Blue (FB) into the cerebellar cortex, followed 3 days later by injection of Nuclear Yellow (NY) into a different region of the cortex, single‐ and double‐labeled cells were found within the LRN. Most LRN‐cerebellar projections were bilateral with ipsi‐lateral preponderance, except for the projection to the paramedian lobule, which was completely ipsilateral.The dorsolateral area of the magnocellular division of the LRN contained cells whose axons branch to terminate in the rostral anterior lobe and the caudal part of the ipsilateral paramedian lobule (hindlimb areas of the cerebellar cortex), while the medial area of the LRN contained cells that supply, via collateral axonal branching, the caudal area of the contralateral anterior lobe and the rostral part of the ipsilateral paramedian lobule (forelimb areas of the cerebellum). Branched LRN‐cerebellar axons projected to both hemispheres and to both sides of the caudal anterior lobe. No axonal branching was evident in the LRN‐cerebellar projection to the rostral anterior lobe. The projection to the anterior and posterior lobe vermis also contained collateral axonal branching.
Electron microscopic study of the rubrocerebellar projection in the cat
Authors: Nakamura Yasuhisa , Kitao Yasuko , Moriizumi Tetsuji , Kudo Motoi 
Published: January 2005

AbstractRubral neurons sending axons to the cerebellar anterior interpositus nucleus (AIN) in the cat were identified light microscopically by labeling them with horseradish peroxidase (HRP). The synaptic organization of these rubral neurons and of their afferents from the cerebral motor cortex and the AIN was also analyzed electron microscopically by combined anterograde degeneration and retrograde HRP‐labeling techniques.In the light microscopic study, either HRP or a mixture of HRP and kainic acid was injected into the AIN. Both of the injections resulted in retrograde labeling of rubrocerebellar projection neurons in the red nucleus on the contralateral side. The labeled neurons were distributed throughout the rostrocaudal extent of the red nucleus: some lay in clusters. Most labeled neurons were small to medium‐sized, although some were large. The injection of HRP into the AIN also resulted in anterograde labeling of cerebellorubral projection fibers terminating in a wider area of the red nucleus on the contralateral side of the injection, whereas the injection of a mixture of HRP and kainic acid showed no anterograde labeling of fibers or terminals.In one set of electron microscopic observations, HRP injections into the AIN were combined with ablation of the motor cortex. Degenerating axon terminals were occasionally found to synapse with both dendrites and neuronal somata labeled with HRP retrogradely.In another set of electron microscopic observations, a mixture of HRP and kainic acid was injected into the AIN in order to label rubrocerebellar projection neurons retrogradely and to bring about degeneration in the cerebellorubral projection fibers anterogradely. Abundant degenerating axon terminals were observed to make axosomatic synaptic contacts with rubral neurons labeled with HRP retrogradely and also with unlabeled rubral neurons.These results indicate that cerebrorubrocerebellar and rubrocerebellorubral monosynaptic circuitries exist which constitute one of the cerebrocerebellar linkages, as well as those linkages via the inferior olivary complex and the pontine nuclei.
Gamma‐aminobutyric acid‐ and glutamic acid decarboxylase‐immunoreactive neurons in the retina of different vertebrates
Authors: Agardh E. , Bruun A. , Ehinger B. , Ekström P. , van Veen T. , Wu J.‐Y. 
Published: January 2005

AbstractThe localization of gamma‐aminobutyric acid (GABA)‐ and L‐glutamate 1 carboxy‐lyase (GAD)‐immunoreactive neurons was compared in the skate, frog, pigeon, chicken, rabbit, and man. Horizontal cells show both GABA and GAD immunoreactivity in the skate, frog, and bird. Certain amacrine cells show GABA and GAD immunoreactivity in all species. The distribution of GABA‐ and GAD‐immunoreactive cell bodies and cell processes was very similar, if not identical, in the skate and man. In the other species, cell populations with GAD immunoreactivity also showed GABA immunoreactivity. However, in the bird, frog, and rabbit, the GABA‐immunoreactive amacrine cells were at least twice as numerous as the GAD‐immunoreactive cells. In birds, the distributions of the GAD and GABA immunoreactivities were different in the sublayers of the inner plexiform layer. The reason for the difference is currently unknown. GABA‐immunoreactive bipolar‐like cells were seen in the frog.
The brainstem projection to the lateral geniculate nucleus in the cat: Identification of cholinergic and monoaminergic elements
Authors: De Lima Ana Dolabeia , Singer Wolf 
Published: January 2005

AbstractThe pontomesencephalic projection to the dorsal lateral geniculate nucleus (dLGN) of the cat was analyzed by combining retrograde transport of rhodamine‐labeled latex spheres and immunohistochemistry. After injections of latex beads into the dLGN, sections of the brainstem were treated immunohistochemically for choline acetyltransferase (ChAT), serotonin (Ser), tyrosine hydroxylase (TH), and dopamine‐beta‐hydroxylase (DBH).Essentially, six regions in the brainstem contained retrogradely labeled cells: the superior colliculus, the parabigeminal nucleus, the dorsal raphe nuclei, the parabrachial area of the central tegmental field, the marginal nucleus of the brachium conjunctivum, and the nucleus coeruleus. Furthermore, isolated retrogradely labeled cells were present in the central nucleus of the raphe, in the cuneiform nucleus, and in the periaqueductal gray. Most serotoninergic double‐labeled cells were found in the medial and lateral divisions of the dorsal raphe nuclei, but a few were also present in the central nucleus of the raphe. In the sections immunostained for ChAT, double‐labeled cells were located in the central tegmental field, in the marginal nucleus of the brachium conjunctivum, and in the nucleus coeruleus. In the sections treated for TH and DBH, double‐labeled cells showed a similar distribution, and like the ChAT(+) cells, they were located mainly in the central tegmental field, in the marginal nucleus of the brachium conjunctivum, and in the nucleus coeruleus. In these regions the cholinergic and noradrenergic cells that projected to the lateral geniculate nucleus were intermingled, the former predominating rostrally and the latter caudally.The majority of retrogradely labeled cells were located in the region of the central tegmental field in the vicinity of the brachium conjunctivum, and most of these cells were also ChAT‐immunoreactive. We, therefore, conclude that the cholinergic projection is the most important of the central core projections ascending to the dLGN.
Fine structure of the ganglion of Cephalodiscus gracilis (pterobranchia, hemichordata)
Authors: Rehkämper G. , Welsch U. , Dilly P. N. 
Published: January 2005

AbstractThe ganglion of Cephalodiscus gracilis M'Intosh 1882 is entirely intra‐epithelial and located in the dorsal epidermis immediately behind the tentacular apparatus that is formed by the mesosome (collar). A characteristic feature of the ganglion is a well‐developed neuropile in which different types of nerve fibres can be discerned, many of which contain small granules with electron‐dense contents. There are no glia‐like cells in association with these fibres. Only slender basal processes of epidermal epithelial cells traverse the neuropile. In the depth of the epithelium the neuropile borders the epidermal basal lamina; apically it is covered by a layer of cell bodies, the majority of which belong to what appear to be ordinary ciliated epidermal cells. Besides these epidermal cells the perikarya of two additional types of cells, which are considered to be neurons, can be discerned. One type is characterised by many rough endoplasmic reticulum cisterns and mitochondria, the other by abundant small, electron‐dense granules. The nuclei of these cells are comparatively pale and contain a prominent nucleolus. The neuron cell bodies do not form a distinct layer; but they are loosely distributed somewhat deeper than those of the ordinary epidermal cells. They probably send off an apical process to the epidermal surface and a basally directed one into the neuropile. The ganglion has been compared to the nervous systems in cnidarians, some spiralians, and especially other hemichordates, echinoderms, and chordates; it is found to be of primitive rather than degenerate nature. Furthermore, the possible functional significance of its close connection to the food‐capturing tentacular apparatus is discussed.