bluuebunny/crossref_metadata_2025_split huggingface dataset:
Locus coeruleus cell loss in the aging human brain: A non‐random process
Authors: Manaye Kebreten F. , McIntire Donald D. , Mann David M. A. , German Dwight C. 
Published: January 2005

AbstractQuantitative neuroanatomical techniques were used to determine whether with aging there is random or systematic loss of locus coeruleus (LC) neurons in the human brain. The cells were identified by immunohistochemical staining for the catecholaminergic enzyme tyrosine hydroxylase and/or by neuromelanin pigment content. Cell locations were mapped, using computer imaging procedures, in horizontal sections spaced 0.5 to 0.8 mm throughout the rostrocaudal extent of the nucleus in 17 cases, from 1 to 104 years of age. Neuromelanin pigment accumulated within the neurons with aging. In brains less than 25 years of age there were many fewer pigment‐containing neurons than tyrosine hydroxylase‐containing neurons; however, by the fifth decade the number of cells identified by the two markers was comparable. From the first to the tenth decade of life there is over a 50% loss of LC neurons: in four cases from “Young” individuals (1–28 years of age) there were 21,084 ± 653 tyrosine hydroxylase immunostained cells (mean ± standard error of the mean) on one side of the brain; in seven cases from “old” individuals (60–82 years of age) there were 16,502 ± 921 pigment‐containing cells; and in the three cases frpm the “oldest” individuals (103–104 years of age) there were 9,493 ± 1,236 pigment‐containing neurons. In both the “old” and “oldest” groups, compared to the “young,” there was significantly greater loss of rostral cells than caudal cells. These data indicate a systematic loss of cells such that the rostral, forebrain‐projecting neurons decrease in number with aging to a greater extent than do the caudal, spinal cord‐projecting neurons. The pattern of cell loss that occurs with normal aging is similar to that found in Alzheimer's disease and in Down's syndrome. © 1995 Wiley‐Liss, Inc.
Glial environment in the developing superior colliculus of hamsters in relation to the timing of retinal axon ingrowth
Authors: Wu Da‐Yu , Jhaveri Sonal , Schneider Gerald E. 
Published: January 2005

AbstractWe have examined the developmental changes of glial cell organization in the superior colliculus of embryonic and neonatal hamsters in reference to the known sequence of retinal axon ingrowth and arborization in the midbrain. Immunolocalization of vimentin, a marker for neuronal and glial cell precursors, reveals a uniform distribution of radially oriented cells, with perikarya located at the ventricular surface and thin, elongated processes fanning out toward the pia. These vimentin‐positive cells, referred to as the lateral radial cells, are present in the tectum from embryonic day (E) 10 (earliest day examined) until approximately postnatal day (P) 5. Vimentin expression in the lateral radial cells decreases markedly during the second week of postnatal life: application of DiI to the ventricular surface reveals that the pial attachment of the lateral radial cells is withdrawn and that the radial processes are gradually pulled back toward the ventricular zone. By P14, virtually no vimentin‐positive radial cells are detectable in the superior colliculus. At no time during development are the lateral radial cells immunopositive for the glial fibrillary acidic protein (GFAP); however, shorter, vimentin‐positive astrocytic profiles can be seen in the tectum, around the time the radial fibers have been withdrawn, suggesting that at least some radial cells are transformed into astrocytes that will colonize the mature colliculus.At approximately E12, a second group of cells, referred to as the midline radial glia, is detected at the tectal midline. These cells are tightly bundled, forming a raphe in the tectum. They are intensely vimentin positive from E13 until at least P14. From the time of birth, the midline radial cells also exhibit intense immunoreactivity for GFAP.The lateral radial cells are present in the superior colliculus prior to and during the period of neurogenesis but remain well past the time when collicular neuronal migration is completed. Pial processes of the lateral radial cells are present within the superficial tectal layers during the time retinal axons are entering this target; they may be involved in directing the growth and initial collateralization of retinotectal axons. Their withdrawal from retinorecipient collicular zones begins at about the time arbors are being elaborated on retinal axons. In constrast, the midline glia become distinct just prior to the time retinal axons enter the superior colliculus and persist during the time retinotectal projections are being fully established. These raphe glia may be involved in maintaining the laterality of the retinotectal projection. © 1995 Wiley‐Liss, Inc.
Histochemical and immunocytochemical localization of nitric oxide synthase in the central nervous system of the goldfish, Carassius auratus
Authors: Brüning Gerold , Katzbach Ralf , Mayer Bernd 
Published: January 2005

AbstractThe distribution of the neuronal type of nitric oxide synthase in the goldfish brain and spinal cord was investigated via NADPH‐diaphorase histochemistry and immunocytochemistry using an antiserum raised against the purified mammalian enzyme. Many structures, including magnocellular neurosecretory cells, motoneurons, mesencephalic trigeminal neurons, and radial glial fibers, were stained by the NADPH‐diaphorase reaction but were not immunoreactive. This nonspecific NADPH‐diaphorase activity was strongly reduced after preincubation of the sections. Therefore, when sections were first reacted for immunofluorescence and, thereafter, stained for NADPH‐diaphorase, a corresponding staining pattern was obtained that allowed the reliable localization of neuronal nitric oxide synthase based on both complementary staining methods.In the telencephalon, positive neurons were concentrated in the ventral and posterior parts of the area ventralis. Many intensely stained neurons were present in various diencephalie nuclei, including the nucleus centralis posterior and the ventromedial nucleus of the thalamus, the nucleus tori lateralis, the nucleus recessus lateralis, the nucleus tuberis posterior, and the central nucleus of the inferior lobe. In the midbrain, neurons containing nitric oxide synthase were located in the periventricular zone of the optic tectum, the nucleus vermiformis, and the nucleus reticularis mesencephali. Specific staining in the cerebellum was concentrated in Golgi cells. In the hindbrain, nitroxergic neurons were numerous in all four sensory nuclei of the trigeminus, in the facial lobe, the superior olive, the inferior reticular formation, and the medial general visceral nucleus of the vagus. The dorsal horn of the spinal cord was enriched with positive neurons. A few strongly stained cells were also present in the ventral horn.In conclusion, neurons capable of synthesizing nitric oxide occur throughout the teleost central nervous system. The presence of nitric oxide synthase in projection areas of most afferent nerves suggests a widespread involvement of nitric oxide in sensory information processing. The distribution of nitric oxide synthase‐containing neurons in certain areas, e. g., the tectum opticum and the spinal cord, indicates an evolutionarily conserved pattern. Similar to the case in other vertebrates, there appears to be no comprehensive overlap between the distribution of nitric oxide synthase and that of any other chemically characterized neuronal population described thus far. However, strongly positive cell groups in the mesencephalic reticular formation suggest the idea of an evolutionarily conserved mesopontine cholinergic system coexpressing nitric oxide synthase. © 1995 Wiley‐Liss, Inc.
Convergence of somatosensory and auditory projections in the avian torus semicircularis, including the central auditory nucleus
Authors: Wild J. Martin 
Published: January 2005

AbstractProjections of dorsal column, spinal, and cochlear nuclei upon the central nucleus of the torus semicircularis (otherwise known as nucleus mesencephalicus lateralis, pars dorsalis, or MLd) and upon other toral nuclei were investigated in pigeon by anterograde and retrograde tracing and electrophysiological methods. The anatomical results showed that caudal regions of the dorsal column nuclei and medial lamina V of the upper four cervical spinal segments have extensive projections upon the contralateral central auditory nucleus and upon other nuclei of the torus, in particular the core portion of the preisthmic superficial area of Puelles et al. (L. Puelles, C. Rrobles, M. Martiez‐de‐la‐Torre, and S. Martinez, 1994, J. Comp. Neurol. 340:98–125). The projections of nucleus angularis were found to terminate throughout most of the contralateral central nucleus except the dorsomedial portion at rostral levels, where the majority of the projections of nucleus laminaris were concentrated. Nucleus angularis (and to a lesser extent nucleus laminaris) was also found to have substantial projections to certain noncentral toral nuclei, in particular to the caudomedial shell nucleus of Puelles et al. (1994). As shown positively with both Nissl and cytochrome oxidase staining and negatively with substance P labeling, this nucleus is a medial extension of more caudal regions of the central nucleus, and it is suggested that it should be included as part of the auditory midbrain.The electrophysiological results confirmed the anatomical findings by showing that evoked potentials and multiunit activity can be recorded throughout the central and noncentral toral nuclei by using electrical stimulation of the radial nerve and auditory click stimuli. The core portion of the preisthmic superficial area, however, can be regarded as a distinct somatosensory nucleus of the midbrain.It is concluded that there is substantial convergence of somatosensory and auditory inputs within both central auditory and noncentral nuclei of the torus semicircularis in pigeon. © 1995 Wiley‐Liss, Inc.
Cellular sites of expression of the neurokinin‐1 receptor in the rat gastrointestinal tract
Authors: Sternini Catia , Su Dennis , Gamp Patrick D. , Bunnett Nigel W. 
Published: January 2005

AbstractIn the digestive system, substance P is an excitatory transmitter to muscle, a putative excitatory neuro‐neuronal transmitter, a vasodilator, and a mediator in inflammatory processes. Many of the biological effects of substance P are mediated by a high‐affinity interaction with the tachykinin receptor neurokinin‐1. The aim of the present study was to identify the sites of expression of this receptor in the rat stomach and intestine by immunchistochernistry with a polyclonal antiserum raised to the intracellular C‐terminal portion of the rat neurokinin‐1 receptor. Neurokinin‐1‐ receptor immunoreactivity is present in a large population of enteric neurons. The relative density of these neurons along the gut is colon > ileum ≫ stomach. In the intestine, stained neurons have a smooth cell body with processes that can be followed within and between plexuses, and make close approaches to other neuronal cells, but do not appear to project outside the plexuses, suggesting that they are interneurons. In the stomach, neurokinin‐1 receptor‐immunoreactive neurons are infrequent and have a poorly defined and irregular shapet Neurokinin‐1 receptor immunoreactivity is also localized to numerous non‐neuronal cells in the inner portion of the circular muscle layer of the small intestine, which have the appearance of small dark smooth muscle cells or interstitial cells of Cajal. These cells are postulated to form a “stretch‐sensitive” system with the deep muscular plexus and thus constitute an important site of regulation of muscle activity. Double labeling immunofluorescence was used to simultaneously localize neurokinin‐1 receptor and substance P/tachykinin immunoreactivities. These experiments demonstrate that in the enteric plexuses, substance P/tachykinin‐immunoreactive varicose fibers encircle the cell bodies of most neurokinin‐1 receptor‐containing neurons, and in the inner portion of the circular muscle layer of the small intestine they lie close to neurokinin‐1 receptor‐immunoreactive non‐neuronal cells. In addition, some enteric‐neurons express both neurokinin‐1 receptor and substance P/tachykinin immunoreactivities. The present study provides strong evidence that the neurokinin‐1 receptor is the tachykinin receptor mediating the actions of substance P on enteric neurons and smooth muscle. © 1995 Wiley‐Liss, Inc.
Retinoid cycling proteins redistribute in light‐/dark‐adapted octopus retinas
Authors: Robles Laura J. , Camacho Jose L. , Torres Steven C. , Flores Anthony , Fariss Robert N. , Matsumoto Brian 
Published: January 2005

AbstractIn cephalopods, the comblex rhodopsin‐retinochrome system serves to regenerate metarhodopsin and metaretinochrome after illumination. In the dark, a solubleprotein, retinal‐binding protein (RALBP), shuttles 11‐cis retinal released from metaretinochrome located in the photoreceptor inner segments to metarhodopsin present in the rhabdoms. While in the rhabdoms, RALBP delivers 11‐cis retinal to regenerate rhodopsin and in turn binds the all‐trans isomer released by metarhodopsin. RALBP then returns all‐trans retinal to the inner segments to restore retinochrome. The conventional interpretation of retinoid cycling is contradicted by immunocytochemical studies showing that, in addition to rhodopsin, retinochrome is present in the rhabdomal compartment, making possible the direct exchange of chromophores between the metapigments with the potential exclusion of RALBP. By using immunofluorescence and laser scanning confocal microscopy, we have precisely located opsin, aporetinochrome, and RALBP in light‐/dark‐adpated octopus retinas. We found differences in the distribution of all three proteins throughout the retina. Most significantly, comparison of cross sections though light‐ and dark‐adpated rhabdoms showed a dramatic shift in position of the proteins. In the dark, opsin and retinochrome colocalized at the base of the rhabdomal microvilli. In the light, opsin redistributed along the length of the microvillar membranes, and retinochrome retreated to a location that is perhaps extracellular. RALBP was present in the core cytoplasm of the photoreceptor outer segments in the dark, and RALBP moved to the periphery in the light. Because of the colocalization of opsin and retinochrome in the dark, we believe that the two metapigments participate directly in chromophore exchange. RALBP may serve to transport additional chromophore from the inner segments to the rhabdoms and may not be immediately involved in the exchange process. © 1995 Wiley‐Liss, Inc.
GABAA‐receptor heterogeneity in the adult rat brain: Differential regional and cellular distribution of seven major subunits
Authors: Fritschy Jean‐Marc , Mohler Hanns 
Published: January 2005

AbstractGABAA‐receptors display an extensive structural heterogeneity based on the differential assembly of a family of at least 15 subunits (α1–6, β1–3, γ1–3, θ, ρl–2) into distinct heteromeric receptor complexes. The subunit composition of receptor subtypes is expected to determine their physiological properties andipharmacological profiles, thereby contributing to flexibility in signal transduction and allosteric modulation. In heterologous expression systems, functional receptors require a combination of α‐, β‐, and γ‐subunit variants, the γ2‐subunit being essential to convey a classical benzodiazepine site to the receptor. The subunit composition and stoichiometry of native GABAA‐receptor subtypes remain unknown. The aim of this study was to identify immunohistochemically the main subunit combinations expressed in the adult rat brain and to allocate them to identified neurons. The regional and cellular distribution of seven major subunits (α1, α2, α3, α5, β2,3, γ2, δ) was visualized by immunoperoxidase staining with subunit‐specific antibodies (the β2‐ and β3‐subunits were covisualized with the monoclonal antibody bd‐17). Putative receptor subtypes were identified on the basis of colocalization of subunits within individual neurons, as analyzed by confocal laser microscopy in double‐ and triple‐immunofluoreseence staining expeximents. The results reveal an extraordinary heterogeneity in the distribution of GABAA‐receptor subunits, as evidenced by abrupt changes in immunoreactivity along well‐defined cytoarchitectonic boundaries and by pronounced differences in the cellular distribution of subunits among various types of neurons. Thus, functionally and morphologically diverse neurons were characterized by a distinct GABAA‐receptor subunit repertoire. The pultiple staining experiments identified 12 subunit combinations in defined neurons. The most prevalent combination was the triplet α1/β2,3/γ2, detected in numerous cell types throughout the brain. An additional subunit (α2, α3, or δ) sometimes was associated with this triplet, pointing to the existence of receptors containing four subunits. The triplets α2/β2,3/γ2, α3/β2,3/γ2, and α5/β2,3/γ2 were also identified in discrete cell populations. The prevalence of these seven combinations suggest that they represent major GABAA‐receptor subtypes. Five combinations also apparently lacked the β2,3‐subunits, including one devoid of γ2‐subunit (α1/α2/γ2, α2/γ2, α3/γ2, α2/α3/γ2, α2/α5/δ). These combinations were selectively associated with small neuron populations, thereby representing minor GABAA receptor subtypes. These results provide the basis for a functional analysis of GABAA‐receptor subtypes of known subunit composition and may open the way for unproved therapeutic approaches based on the development of subtype‐selective drugs. © 1995 Wiley‐Liss, Inc.
Compartmental organization of layer IVA in human primary visual cortex
Authors: Yoshioka Takashi , Hendry Stewart H. C. 
Published: January 2005

AbstractImmunostaining for three neuronal proteins, nonphosphorylated neurofilament protein (with antibody SMI‐32), calbindin, and parvalbumin, was used to examine the organization of layer IV in human primary visual cortex (area 17 or V1) specifically to determine whether, similar to the case in macaque V1, layer IVA is present and is divided into neurochemically distinct compartments. All three proteins are expressed by neurons that are unevenly distributed in layer IV of human V1; immunostaining for each protein includes a thin band corresponding to layer IVA of classic cytoarchitectonic studies. In this band, nonphosphorylated neurofilament protein immunoreactivity is present in relatively broad clusters of pyramidal cell somata and dendrites that appear as upwardly protruding parts of intense immunostaining in layer IVB, whereas immunoreactivity for calbindin and parvalbumin exists in somata of nonpyramidal neurons and in thin, dense clusters of punctate profiles. In tangential sections through layer IVA, the three proteins are seen in distinct compartments. Calbindin‐ and parvalbumin‐immunostained neurons make up a thinly walled honeycomb or lattice, whereas neurons immunostained for nonphosphorylated neurofilament protein occupy the central lacunae. Direct comparison shows that neurons immunostained for calbindin occupy regions in layer IVA complementary to those immunostained for nonphosphorylated neurofilament protein. These data demonstrate a basic similarity in the organization of layer IV in macaques and humans. Layer IVA specifically is organized into complementary and neurochemically distinct compartments, including what appears to be a geniculocortically innervated and parvicellular‐driven lattice and the interstitial lacunae formed by the periodic, upward protrusion of magnocellular‐dominated layer IVB neurons. © 1995 Wiley‐Liss, Inc.
Complementary expression of parvalbumin and calbindin D‐28k delineates subdivisions of the rabbit medial geniculate body
Authors: de Venecia Ronald K. , Smelser Chad B. , Lossman Scott D. , McMullen Nathaniel T. 
Published: January 2005

AbstractThe complementary pattern of immunohistochemical staining for the calcium‐binding proteins parvalbumin (PV) and calbindin D‐28k (CB) was used to delineate four major subdivisions of the rabbit medial geniculate body (MGB). PV immunoreactivity predominates in the ventral and medial divisions, whereas CB‐immunoreactiv cells characterize the dorsal and internal divisions. The ventral nucleus is strongly PV+ due to dense neuropil labeling and moderately labeled somata. The medial nucleus contains both medium‐sized and large PV+ somata, as well as thick PV+ axons and terminals. The wedge‐shaped internal nucleus, composed of densely labeled CB+ cells, separates the dorsal and ventral nuclei rostrally, and expands caudally to encapsulate the posterior MGV. Large multipolar CB+ neurons with radiate dendrites characterize the dorsal nucleus. The differential expression of PV and CB also distinguishes the deep dorsal and superficial dorsal subnuclei in the dorsal division and a ventrolateral component in the ventral division. A comparison with studies of MGB connectivity in a variety of species suggests that PV immunoreactivity is highest in subdivisions that receive a substantial input from the central nucleus of the inferior colliculus and that project to primary auditory cortex. In contrast, CB immunoreactivity characterizes nuclei that receive input primarily from other sources, such as the paracentral nuclei of the inferior colliculus, the lateral tegmentum, and the spinal cord, and that project to secondary auditory areas. The ability of calcium‐binding protein immunohistochemistry to delineate neuronal compartments across indistinct cytoarchitectonic borders makes it a powerful tool for guiding future connectional and physiological studies of the MGB. © 1995 Wiley‐Liss, Inc.
Projections from the cochlear nucleus to the superior paraolivary nucleus in guinea pigs
Authors: Schofield Brett R. 
Published: January 2005

AbstractAxonal tracing techniques were used to study the projection from the cochlear nucleus to the superior paraolivary nucleus in guinea pigs. Different tracers were used to identify the cell types that give rise to the projections, the morphology of their axons, and the cell types that they contact in the superior paraolivary nucleus. Injections of Fluoro‐Gold or peroxidase‐labeled WGA and HRP into the superior paraolivary nucleus labeled multipolar cells and octopus cells bilaterally in the ventral cochlear nucleus, mainly on the contralateral side. Injections of PHAL into the ventral cochlear nucleus labeled two types of axons in the superior paraolivary nucleus. Thin axons branch infrequently and give rise primarily to small, en passant boutons. Thick axons have larger boutons, many of which are terminal boutons that arise from short collaterals. Thin axons appear to originate from multipolar cells, whereas thick axons probably originate from octopus cells. Both types are found bilaterally after an injection into the ventral cochlear nucleus on one side. Individual thick or thin axons may contact multiple cell types in the superior paraolivary nucleus. Individual cells in the superior paraolivary nucleus can receive convergent input from both thick and thin axons. Combined anterograde and retrograde transport of different fluorescent tracers was used to identify the projections of the cells in the superior paraolivary nucleus that receive inputs from the ventral cochlear nucleus. Cells in the superior paraolivary nucleus that projected to the ipsilateral cochlear nucleus or to the ipsilateral inferior colliculus appeared to be contacted by axons that were labeled by anterograde transport from the contralateral ventral cochlear nucleus. Thus the projections to the superior paraolivary nucleus are in a position to affect the activity in both ascending and descending auditory pathways. © 1995 Wiley‐Liss, Inc.