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At least 127 records · Page 7Linked to original sources
PubMed1993

Further observations on Tau-positive glia in the brains with progressive supranuclear palsy.

The previously reported unusual, Tau-positive glia with astrocytic morphology seen in brain tissues from cases of progressive supranuclear palsy (PSP) were re-examined immunohistochemically using antibodies to CD44 and vimentin, as well as Alz-50. Four brains of PSP cases, one of whom had atypical clinical features, were examined. All four cases showed the unusual glia which were positive to Alz-50 and anti-CD44 antibodies, but negative to anti-vimentin antibody. Ultrastructurally, they had either paired nucleated or lobulated nuclei and the cytoplasm frequently contained lipofuscin pigment. The CD44 was located on the surface of the cell bodies and their processes. Such glia were most numerous in the striatum in all cases. They also appeared in the cortex and some subcortical nuclei in the three typical cases. They were not seen in the lower brain stem or cerebellum. In their morphological characteristics and regionally specific appearance, these unusual glia seemed similar to the Alzheimer type I glia which are commonly seen in hepatic encephalopathy or Wilson's disease.

Aged↗
PubMed1977

Studies of auricular catecholamines by fluorescence histochemistry in various heart diseases of man.

A comparative histochemical and clinical study concerning the state of the intrinsic adrenergic innervation of the human atrial myocardium was carried out, using the glyoxylic acid-induced fluorescence histochemical method. Specimens from the right auricular appendage were obtained during open-heart surgery from patients suffering from 1. ischaemic heart disease (IHD), 2. atrial septal defect of the secundum type (ASD), and 3. left-sided univalvular or multivalvular heart disease (VHD) with or without congestive heart failure (CHF) experienced prior to surgery. In the IHD group the densities of both the perivascular and the "free" myocardial adrenergic nerve net were greater than in the ASD group and especially in the VHD/CHF group. Secondly, the intensity of fluorescence of the adrenergic structures was generally higher in the IHD group than that in the VDH/CHF group. Further, the average size of the varicosities, the number of varicosities per given length of axon, and the proportional share of the large varicosities were greater in the IHD group than in the ASD and VHD/CHF groups. The difference between the IHD and ASD groups was not great but was obvious in any case. In some patients with VHD/CHF fluorescing axons were observed only occasionally, and the tiny varicosities exhibited a hardly discernible fluorescence. Thus the amount of noradrenaline (NA) in the adrenergic fibres in the IHD group seems to be higher than in the ASD and especially VHD/CHF groups. The level of NA in the IHD group is assumed to constitute a contributory factor in both intracellular metabolic changes and the systemic changes typical of myocardial ischaemia and infarction. In one patient with IHD and in six patients with VHD/CHF with significantly higher heart volume (mean+/-SD) compared with the rest of the patients (P less than 0.001), huge local axonal accumulations of NA in the form of "droplet fibres" were found. These enlarged, bulging adrenergic axons are assumed to be a consequence of mechanical trauma with stretching or disruption of the axons due to myodegenerative processes. It is further assumed that these "droplet fibres" are relatively common in those patients with diseased myocardium. They may constitute an extra contributory factor to the tendency to arrhythmiility of non-atuomatic tissue.

Adult↗
PubMed1987

Immunocytochemical demonstration of neuropeptides and serotonin in the nervous systems of adult Schistosoma mansoni.

In the nervous system of adult Schistosoma mansoni, neuropeptides and serotonin were demonstrated immunocytochemically. Neurons and nerve fibers immunoreactive to anti-FMRF-amide, anti-substance P, anti-leu-enkephalin, and anti-growth hormone releasing factor were found in the central and peripheral nervous system. The peptidergic nerve cell bodies in the bilobed brain are large and often multipolar; those in the peripheral nerve net are smaller and often bipolar. Sensory receptors of two morphologically different types were found along the surface of the worm. They are mainly immunoreactive to anti-substance P and anti-leu-enkephalin, and, to a lesser degree, to anti-FMRF-amide. Serotonin-immunoreactive fibers are found in the central and peripheral nervous elements as well as in sensory endings.

Animals↗
PubMed1974

A review of lamination in area 17 of the visual cortex Macaca mulatta.

This paper develops a concordance of methods for designating laminae in the primate striate cortex. The classic notation schemes of Ramón y Cajal, Brodmann, and von Bonin and four recent modifications are described in words and photomicrographs. The recent trend toward adopting a lamination scheme that effects a division of cells into recognizable layers and at the same time reflects their connections is considered. Since a single, consistent plan for lamination of the visual cortex would facilitate communication among investigators, it is suggested that Brodmann's original scheme be followed as the most generally useful and applicable.

Animals↗
PubMed1978

A second sensory--motor--interneuron with neurosecretory granules in Hydra.

Using serial-sectioning techniques for conventional transmission and high-voltage electron microscopy, we characterized the ultrastructural features and synaptic contacts of the sensory cell in tentacles of Hydra. The sensory cell has an apical specialization characterized by a recessed cilium surrounded by three rodlike stereocilia. This ciliary--stereociliary complex constitutes the receptive or dendritic pole of the sensory cell. The dense filamentous cores of the stereocilia project proximally into a narrow circumciliary cytoplasmic region connected by septate junctions to marginal processes of an enveloping epitheliomuscular cell. The central cilium has a characteristic marginal flare midway along its length and a dense filamentous substructure at its base. Pairs of branched, striated rootlets extend from the axial centriole into a mitochondria-rich region of the cell. Pigment-like granules are present in the cytoplasm around the circumciliary space. The perikaryon is characterized by an elongate nucleus surrounded by a narrow rim of cytoplasm containing prominent Golgi complexes, assorted vacuoles and dense-cored vesicles, free ribosomes, short segments of rough endoplasmic reticulum, microtubules, glycogen particles, and lipid droplets. Generally, one or two thin, naked axons extend laterally from the perikaryon into the nerve net region above the myonemes of the large epitheliomuscular cells. Within the axons are found occasional aggregates of dense-cored vesicles and en passant synapses characterized by the presence of clear or dense-cored vesicles in contact with paramembranous densities and associated intracleft cross filaments. Using these ultrastructural criteria, we demonstrated for the first time that the granule-containing sensory cells have synaptic contacts with other neurons, nematocytes, and epitheliomuscular cells hence, we considered these cells to be sensory--motor--interneurons with neurosecretory granules. We hypothesize that this unique, apparently multifunctional neuron may be a modern representative of a primitive stem cell that give rise evolutionarily to the sensory cells, motor neurons, interneurons, and neurosecretory cells of higher animals.

Animals↗
PubMed1997

Roles of a neuronal cell-surface molecule, neuropilin, in nerve fiber fasciculation and guidance.

Neuropilin is a cell-surface glycoprotein that was first identified in Xenopus tadpole nervous tissues and then in chicken and mouse. The primary structure of neuropilin is highly conserved among these vertebrate species. The extracellular part of the molecule is composed of three domains referred to as a1/a2, b1/b2, and c, each of which is expected to be involved in molecular and/or cellular interactions. Neuropilin can mediate cell adhesion by heterophilic molecular interaction. In all vertebrate species examined, the neuropilin protein is restricted to axons of particular neuron classes, and at stages when axon growth is active. The gain and loss of function of neuropilin in developing mouse embryos causes defasciculation and incorrect sprouting of nerve fibers. These findings suggest that neuropilin serves in a variety of neuronal cell interactions by binding to a variety of molecules, and that it plays essential roles in nerve fiber fasciculation and guidance.

Animals↗
PubMed2006

Aldolase C/zebrin II is released to the extracellular space after stroke and inhibits the network activity of cortical neurons.

Cell death after stroke involves apoptotic, autophagocytic and necrotic mechanisms which may cause the release of cytosolic proteins to the extracellular space. Aldolase C (AldC) is the brain specific isoform of the glycolytic enzyme fructose-1,6-bisphosphate aldolase. According to its characteristic striped expression pattern in the adult cerebellum AldC is also termed zebrin II. Here, we demonstrate release of AldC into the cerebrospinal fluid (CSF) after stroke in vivo. Studies with cell cultures confirmed that AldC is released to the extracellular space after hypoxia. Moreover, addition of purified recombinant AldC to networks of cortical neurons plated on multielectrode arrays reversibly inhibited the spontaneous generation of action potentials at AldC concentrations which can be expected to occur after lesions of the human cerebral cortex. This mechanism could be relevant in the pathogenesis of the electrophysiological changes in the penumbra region after stroke.

Adult↗
PubMed1994

Immunohistochemical localization of the neuron-specific glucose transporter (GLUT3) to neuropil in adult rat brain.

The precise histologic localization of GLUT3, a glucose transporter thought to be restricted to neurons, is unknown. Using a high-affinity, specific antiserum against rodent GLUT3 for immunocytochemistry, light microscopic staining concentrates heterogeneously in the neuropil in a region- and lamina-specific manner; intense staining characterizes areas with high rates of glucose utilization such as inferior colliculus and pyriform cortex. Neuropil localization with little perikaryal staining suggests that GLUT3 may provide the energy needed locally for synaptic transmission.

Animals↗
PubMed1983

Neurophysiology of adult male Schistosoma mansoni.

From the studies on the neurophysiology of schistosomes it appears that in spite of the unique hexilaminar arrangement of the tegument's outer membrane, it has biophysical properties not markedly different from those of a variety of other multi-dimensional syncytia. The close electrical coupling of the muscle and tegument must be taken into account when one attempts to define sites and modes of action of drugs which affect motor activity. Agents which disrupt muscle function in the schistosome may exert their action indirectly by way of an effect on the tegumental membrane. The syncytial nature of the musculature and the possibility that longitudinal contraction waves are myogenic suggests that neurotransmitters may simply function as modulators of muscle activity as is the case for many vertebrate visceral muscles. External recordings indicate the presence of a variety of electrically active tissues within the schistosomes. There is no clear correlation of this activity with longitudinal muscle activity or with active membrane responses in this muscle. From this it would appear the bulk of this activity may have its origins in tissues other than the longitudinal muscle such as other muscle groups, nerve trunks, or the peripheral nerve net.

Animals↗
PubMed1995

Local circuit neurons of the prefrontal cortex in schizophrenia: selective increase in the density of calbindin-immunoreactive neurons.

Schizophrenia has been reported to be associated with alterations in GABAergic local circuit neurons of the prefrontal cortex. In this study, immunocytochemical techniques and antibodies against the calcium-binding proteins calbindin (CB) and calretinin (CR) were used to determine the laminar distribution and relative density of separate subpopulations of local circuit neurons in prefrontal cortical areas 9 and 46 from five pairs of schizophrenic and control subjects, matched for age, sex, and post-mortem interval. The laminar distribution pattern of CB-immunoreactive local circuit neurons was similar in both schizophrenic and control subjects. In both prefrontal regions, however, the density of CB-labeled neurons was 50-70% greater in schizophrenic subjects compared with control subjects, with cortical layers III and V/VI being preferentially affected. In contrast, the density of CR-IR neurons did not differ significantly between schizophrenic and control subjects. These findings reveal a selective increase in the density of a subpopulation of GABAergic local circuit neurons in the prefrontal cortex. Although other explanations for these observations must be considered, they may be consistent with the hypothesis that gene expression in GABAergic neurons is altered in schizophrenia.

Adult↗
PubMed1995

Functional repair of striatal systems by neural transplants: evidence for circuit reconstruction.

Intrastriatal grafts of nigral and adrenal tissues have been found to be effective in alleviating many of the simple motor and sensorimotor deficits associated with lesions of the nigrostriatal dopamine system. However, the mechanisms by which such grafts exert their effects may be less specific than originally conceived, and both pharmacological and trophic actions play an essential role. Damage to intrinsic cortico-striatal circuits are unlikely to prove similarly amenable to such diffuse mechanisms of repair. Nevertheless, striatal grafts have been found to alleviate cognitive and motor deficits after excitotoxic lesions of the neostriatum. Accumulating evidence suggests that in this particular case many aspects of functional recovery may indeed be attributable to the striatal grafts providing an effective functional reconstruction of damaged neuronal circuits within the host brain.

Adrenal Glands↗
PubMed1991

Immunohistochemical localization of neuron-specific enolase and calcitonin gene-related peptide in pig taste papillae.

Immunoreactivity to neuron-specific enolase (NSE), a specific neuronal marker, and calcitonin gene-related peptide (CGRP) was localized in lingual taste papillae in the pigs. Sequential staining for NSE and CGRP by an elution technique allowed the identification of neuronal subpopulations. NSE-staining revealed a large neuronal network within the subepithelial layer of all taste papillae. NSE-positive fibers then penetrated the epithelium as isolated fibers, primarily in the foliate and circumvallate papillae, or as brush-shaped units formed by a multitude of fibers, especially in the fungiform papillae and in the apical epithelium of the circumvallate papilla. Taste buds of any type of taste papillae were found to express a dense subgemmal/intragemmal NSE-positive neuronal network. CGRP-positive nerve fibers were numerous in the subepithelial layer of all three types of taste papillae. In the foliate and circumvallate papillae, these fibers penetrated the epithelium to form extragemmal and intragemmal fibers, while in the fungiforms, they concentrated almost exclusively in the taste buds as intragemmal nerve fibers. Intragemmal NSE- and CGRP-positive fiber populations were not readily distinguishable by typical neural swellings as previously observed in the rat. The NSE-positive neuronal extragemmal brushes never expressed any CGRP-like immunoreactivity. Even more surprising, fungiform taste buds, whether richly innervated by or devoid of NSE-positive intragemmal fibers, always harboured numerous intragemmal CGRP-positive fibers. Consequently, NSE is not a general neuronal marker in porcine taste papillae. Our observations also suggest that subgemmal/intragemmal NSE-positive fibers are actively involved in synaptogenesis within taste buds. NSE-positive taste bud cells were found in all three types of taste papillae. CGRP-positive taste bud cells were never observed.

Animals↗
PubMed1994

Telencephalin: a neuronal area code molecule?

Cell adhesion molecules (CAMs) with expression restricted to specific developmental and structural units of the brain and/or selective neuronal types would play critical roles in the formation of functional neuronal networks. In this article, we summarize recent progress in knowledge on a brain segment-specific CAM, telencephalin (TLN). TLN has the following characteristic properties. (1) TLN is a neuronal glycoprotein whose expression is restricted within telencephalon, the most rostal segment of the brain. (2) TLN is localized to the soma-dendritic membrane of subsets of telencephalic neurons, but not to the axonal membrane. (3) Abrupt appearance of TLN around birth parallels the timing of dendritic development and synapse formation in the telencephalon. (4) TLN belongs to the immunoglobulin superfamily and its structure is most closely related to intercellular adhesion molecules (ICAMs)-1 and -3. These findings suggest that TLN is the first example of dendrite-associated cell adhesion molecules (DenCAMs) and that TLN may be involved in the brain segmental organization, cell-cell interactions during dendritic development, and maintenance of functional neuronal networks. We discuss the possibility that TLN is an area code-like address signal that is displayed selectively by telencephalic neurons and is decoded by specific subsets of growing axons to make proper synaptic connections.

Animals↗
PubMed1986

Transplantation of dissociated foetal serotonin neurons into the transected spinal cord of adult rats.

Twenty adult rats underwent a complete section of the spinal cord at the lower thoracic level. One week later, 15 of them received a cell suspension obtained from raphe nuclei of 14-day-old foetuses into the distal fragment of the spinal cord. They were sacrificed after survival periods of 10-60 days, and vibratome sections of the spinal cord were processed for immunocytochemical detection of serotonin (5-HT). The control, non-transplanted animals showed a total absence of 5-HT immunoreactivity below the section, whereas the transplanted rats showed many immunoreactive 5-HT perikarya in the graft region, some at a distance of up to 10 mm, and a progressive innervation of the whole grey matter extending at least over 20 mm from the graft site.

Animals↗
PubMed1993

Enteric nerve fibers of holothurians are recognized by an antibody to acetylated alpha-tubulin.

The distribution of immunoreactivity to 6-11B-1, a monoclonal antibody that labels acetylated alpha-tubulin, was studied in the radial nerve and intestinal system of holothurians. As shown previously for other species, this antibody recognizes cilia and nerve fibers in Holothuria glaberrima and Holothuria mexicana. Thus, anti-acetylated alpha-tubulin can be used as a marker for nerve fibers in the enteric nervous system.

Acetylation↗
PubMed2005

Alteration and recovery of appetitive behaviour following nerve section in the starfish Asterias rubens.

The starfish Asterias rubens is an invertebrate deuterostome whose nervous system shows remarkable regenerative properties. To understand when full functionality of a damaged part of the nervous system recovers, and to follow nerve regeneration in detail, we carried out behavioural experiments with 29 starfishes that had the nerve in one of the arms sectioned in a mid-arm position. Loss and recovery of normal behaviour was followed by video analysis of animal performance in an appetitive behavioural test. When compared to 13 control (unoperated) animals, the appetitive response of freshly sectioned animals is normal initially, progressively deteriorates up to 40 days after the lesion, and then gradually improves until 60 days, when recovery is complete. This is true only when one of the leading arms in the appetitive test is a sectioned arm; turning the starfish so that both the leading arms facing the prey are unlesioned, results in normal behaviour even at 40 days after the cut. Thus, regeneration is a multi-step process whose time course coincides with anatomical regeneration. At intermediate times the animals have coordination problems in an appetitive behaviour test and these give some insights into how arms may inter-communicate to organize concerted movements.

Animals↗