bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurofilament mRNA is reduced in Parkinson's disease substantia nigra pars compacta neurons
Authors: Hill William D. , Arai Motomi , Cohen Jeffrey A. , Trojanowski John Q.
Published: January 2005

Lewy bodies are filamentous neuronal inclusions characteristic of Parkinson's disease, and neurofilament triplet proteins are the major components of the filaments in Lewy bodies. Since the neurofilament proteins found in Lewy bodies are abnormally phosphorylated and partially degraded, the formation of Lewy bodies may be due to the defective metabolism of these proteins, and this could lead to impairments in the structure and function of neurofilament rich neuronal processes (i.e., large caliber axons). To gain further insights into the metabolism of neurofilaments in Parkinson's disease, we evaluated neurofilament mRNA levels by semiquantitative in situ hybridization histochemistry in postmorten tissues from Parkinson's disease and control subjects. Substantia nigra pars compacta neurons were examined with digoxigenin‐UTP labeled cRNA probes to the heavy and light neurofilament mRNAs. The relative abundance of these mRNAs was measured by videodensitometric image analysis of chromogenic reaction product. Using this approach, we demonstrated that the levels of both heavy and light neurofilament mRNAs were reduced in Parkinson's disease substantia nigra pars compacta neurons. Additionally, the levels of heavy neurofilament mRNA were lowest in Lewy body containing neurons in the Parkinson's disease cases. These results suggest that the formation of neurofilament‐rich Lewy bodies in substantia nigra pars compacta neurons is associated with reduced levels of the heavy and light neurofilament mRNAs in Parkinson's disease. Thus, it is possible that the accumulation of abnormal neurofilament proteins in Lewy bodies and diminished neurofilament mRNAs contribute to the degeneration of substantia nigra pars compacta neurons in Parkinson's disease. © 1993 Wiley‐Liss, Inc.
Morphology of the vasopressin‐like immunoreactive (VPLI) Neurons in Many Species of Grasshopper
Authors: Tyrer N. M. , Davis N. T. , Arbas E. A. , Thompson K. S. J. , Bacon J. P.
Published: January 2005

It has previously been shown that the pair of vasopressin‐like immunoreactive (VPLI) neurons of the locust, Locusta migratoria, have cell bodies on the ventral midline of the suboesophageal ganglion and extensive arborisations in all ganglia of the central nervous system. In the present study, we have stained vasopressin‐like immunoreactive neurons in 16 additional species of grasshopper, and consistently find this pair of extensive neurons: we assume these to be interspecies homologues. However, the anatomy of these neurons falls into two morphological types: the first, typified by Schistocerca gregaria, has most of its processes distributed in dorsal and lateral neuropil of all ganglia; the second, typified by Locusta migratoria, is equally extensive in its arborisation, but the distribution of branches is shifted peripherally into the optic lobes and the proximal portions of peripheral nerves. It has been suggested that the peripheral fibres in Locusta migratoria are neurohaemal organs for the release of a vasopressin‐like diuretic peptide. Our sample of 17 Acridoid species has deliberately selected animals from very different habitats, but our extensive survey of VPLI anatomy shows that peripheral fibres are only present in species from the subfamily Oedipodinae (of which Locusta migratoria is a member) and that no peripheral fibres are present in any of the species from the 4 other subfamilies of the Acridoidea that we have examined. The presence of peripheral fibres is therefore determined by phylogeny and not by habitat.

The absence of peripheral VPLI fibres in most grasshopper species examined in this study probably means that the release of putative diuretic hormone from VPLI to control water homeostasis cannot be a conserved function of this ubiquitous neuron. In contrast, the extensive central arborisations and rare antigenicity, which are highly conserved features of the VPLI neuron in all those grasshoppers we have examined, suggests that any conserved role is more likely to be central. A central role for the VPLI neuron has yet to be determined. © 1993 Wiley‐Liss, Inc.
Chronic peripheral nerve section results in a rearrangement of the central axonal arborizations of axotomized A beta primary afferent neurons in the rat spinal cord
Authors: Shortland Peter , Woolf Clifford J.
Published: January 2005

In order to investigate the reorganization of the neuropil of the dorsal horn following peripheral nerve injury, the central terminal arborizations of 35 A beta primary afferent neurons, chronically injured by a cut and ligation of the sural nerve 6–12 weeks previously, were studied by the intra‐axonal injection of horseradish peroxidase. Their morphology was compared to 13 intact sural nerve hair follicle afferents. Following axotomy, three kinds of morphological abnormalities were observed in the collateral arbors of the 26 afferents that were hair follicle‐like. Atrophy with thin stem axons and reduced terminal branch patterns with few boutons was seen in 5 afferents. Sprouting of bouton‐containing terminals into lamina I and IIo was found in 8 afferents. Finally, abnormal arborization patterns in the deeper laminae were observed in 29% of the collateral arbors. Changes included the loss in some arbors of a flame‐shaped appearance, which is characteristic of hair follicle afferents, atypical branching patterns and ventrally directed axons producing wider and deeper arbors, compared to normal.

Axotomy also caused a disruption of the normal somatotopic organizaiton of sural nerve A beta afferents. This disruption manifested as a variability in the normally mediolaterally restricted terminal sheet, with a consequent loss of the strict somatotopic register in the rostrocaudal direction. Damage to the peripheral axon of A beta primary afferents induces a structural reorganization of their central terminals in the dorsal horn of the spinal cord, which may modify sensory input to the central nervous system.
Axonal regeneration is associated with glial migration: Comparison between the injured optic nerves of fish and rats
Authors: Blaugrund E. , Lavie V. , Cohen I. , Solomon A. , Schreyer D. J. , Schwartz M.
Published: January 2005

The central nervous systems of mammals and fish differ significantly in their ability to regenerate. Central nervous system axons in the fish readily regenerate after injury, while in mammals they begin to elongate but their growth is aborted a the site of injury, an area previously shown to contain no glial cells. In the present study we compared the ability of glial cells to migrate and thus to repopulate the injured area in fish and rats, and used light and electron microscopy in an attempt to correlate such migration with the ability of axons to traverse this area. One week after the optic nerve was crushed, both axonal and glial responses to injury were similar in fish and rat. In both species glial cells were absent in the injured area (indicated by the disappearance of glial fibrillary acidic protein and vimentin immunoreactive cells from the site of injury in rat and fish, respectively), while at the same time axonal growth, indicated by expression of the growth‐associated protein GAP‐43, was restricted to the proximal part of the nerve. In fish, 2 weeks after the crush, GAP‐43 staining (i.e., growing axons) was seen at the site of injury, in association with migrating vimentin‐positive glial cells. One week later the site of injury in the fish optic nerve was repopulated by vimentin‐positive glial cells, and GAP‐43‐positive axons had already traversed the site of injury and reached the distal part of the nerve. In contrast, the site of injury in the rat remained devoid of glial fibrillary acidic protein immunoreactive cells, and the expression of GAP‐43 by growing axons was still restricted to the proximal part of the nerve. Double‐labeling experiments and transmission electron microscopy performed 2 weeks after crush injury of the fish optic nerve revealed that the frontier of axonal growth (i.e., the leading growth cones) appeared to be 200–300 μm ahead of the nearest vimentin‐positive glial cells. The leading growth cones were associated with other cells, presumably glial precursors, that seemed to have a high migratory potential. We suggest that the ability of fish glial precursor cells to migrate into the injured area may contribute to the potential of growing axons to traverse this area. The failure of glia and glial precursor cells to migrate into the injured area in the rat may partially account for the failure of rat axons to enter and traverse the injured area.
Cerebellar nuclear projections from the basilar pontine nuclei and nucleus reticularis tegmenti pontis as demonstrated with PHA‐L tracing in the rat
Authors: Mihailoff Gregory A.
Published: January 2005

Small iontophoretic placements of the orthogradely transported axonal tracer Phaseolus vulgaris leucoagglutinin (PHA‐L) were made in portions of the basilar pontine nuclei (BPN) or nucleus reticularis tegmenti pontis (NRTP) to determine if these cell groups provide projections to the cerebellar nuclei (CN) in the rat and if so, to visualize the morphology of the axons and teminals and illustrate any topographical organization in this system. Axons that originated from BPN or NRTP neurons and contained PHA‐L were visualized by an immunohistochemical procedure that involved sequential incubation of tissue sections with goat anti‐PHA‐L antibody, biotinylated rabbit anti‐goat immunoglobulin, and a biotin‐avidin‐peroxidase conjugate.

Following injections of PHA‐L restricted to ventral and medial portions of the BPN, labeled fibers were observed in the brachium pontis, the white matter dorsal to the CN, and to a lesser extent, in the white matter of the parafloccular stalk. Labeled preterminal axons entered the CN and gave rise to beaded axons that arborized primarily within dorsal portions of the lateral, interposed, and medial cerebellar nuclei. Injections of PHA‐L restricted to either lateral portions of the BPN or ventrolateral regions of NRTP produced labeled fibers in the cerebellum that most frequently involved the parafloccular stalk and ventral portions of the CN. In contrast, dorsomedial NRTP injections resulted in the presence of labeled fibers both in the dorsal cerebellar white matter and the parafloccular stalk as well as dorsal and ventral portions of the CN. With the exception of the rostral and medial territory of interpositus anterior which received very sparse input, all portions of each CN subdivision seemed to exhibit some degree of terminal labeling. The density of labeled axon terminals in the CN appeared to be somewhat greater in the NRTP‐injected cases compared to BPN‐injected animals. These observations indicate that in the rat, both the BPN and NRTP contain neurons whose axons distribute to the CN. It is likely that most of the axons which project to the CN are collaterals of fibers that continue into the cerebellar cortex as mossy fibers but confirmation of this point must await further investigation. In light of the extensive projections from the cerebral cortex to the BPN and NRTP, this axonal system provides the cerebral cortex with a relatively direct route of access to the CN via one synapse in the BPN or NRTP.
Geometry of the projection of the visual field onto the superior colliculus of the wallaby (Macropus eugenii). II. Stability of the projection after prolonged rearing with rotational squint
Authors: James A. C. , Mark R. F. , Sheng X.‐M.
Published: January 2005

At about the time of eye opening, one eye of seven tammar wallaby pouch young was surgically rotated about the optic axis by approximately 90°. In adulthood the projection of the visual field through the rotated eye onto the contralateral superior colliculus was mapped electrophysiologically. Although apparently distorted, the projection could be coherently rerotated mathematically to a reasonable copy of the normal projection from the opposite eye of the same animal, including details such as regional variations of the magnification factor. The same was true of three adult animals in which the eye rotation was done after anaesthesia immediately before the electrophysiological mapping. In animals in which the visual field seen through one eye, the other being normal, was rotated for the entire period of visual experience, there was no sign of compensation or rearrangement of the topographic map. Retinocollicular synaptic connections appear unmoved by such discordant visual experience.
Orderly migration of neurons to the principal sensory nucleus of the trigeminal nerve of the rat
Authors: Al‐Ghoul Walid M. , Miller Michael W.
Published: January 2005

As nuclei in the central nervous system develop, neurons actively migrate from their site of generation to their permanent residence. This study examines the spatiotemporal sequence of the migration of neurons to the principal sensory nucleus of the trigeminal nerve (PSN) of the rat. Tritiated thymidine autoradiography and bromodeoxyuridine immunohistochemistry were used to examine the spatiotemporal patterns of migration of PSN neurons born on gestational day (G) 12 (early‐generated neurons) and of those born on G14 (late‐generated neurons). The final residence of early‐ and late‐generated neurons was determined by injecting a thymidine analog into a pregnant rat on G12 or G14 and sacrificing the pups on postnatal day (P) 30. Early‐ and late‐generated neurons were distributed medially and laterally, respectively. The schedule of the migration of PSN neurons was also determined. A few pioneer neurons born on G12 reached the PSN by G14; however, the last of the neurons born on G12 arrived in the PSN by G18. The migration of neurons born on G14 was completed 2–6 days later than that of the early‐generated neurons. The path followed by migrating neurons was delineated by radial glial fibers. These processes were identified in the developing metencephalon by RAT‐401 immunohistochemistry. Radial glial fibers extended from the lateral part of the ventricular zone through the tegmentum and the PSN to the surface of the metencephalon external to the sensory tract of the trigeminal nerve. RAT‐401‐immunoreactive processes were detected during the period of neuronal migration, but disappeared by P5. Thus, the migration of PSN neurons follows an inside‐to‐outside sequence, which apparently is organized by radial glial fibers. The inside‐to‐outside sequence of neuronal migration directly opposes the outside‐to‐inside gradient of synaptogenesis.
Ontogeny of calcitonin gene‐related peptide immunoreactivity in rat lumbar motoneurons: Delayed appearance and sexual dimorphism in the spinal nucleus of the bulbocavernosus
Authors: Forger Nancy G. , Hodges Lynn L. , Breedlove S. Marc
Published: January 2005

Immunoreactivity for calcitonin gene‐related peptide (CGRP) has been observed in both adult and embryonic rat motoneurons. However, the developmental pattern of CGRP expression in motoneurons has not been systematically examined and the role of CGRP in neuromuscular development is poorly understood. We have mapped the ontogeny of CGRP‐like immunoreactivity in three motoneuron pools of the rat lumbar spinal cord from birth through adulthood. Immunoreactivity was uniformly high in lateral horn motoneurons (the retrodorsolateral nucleus) of males and females at all ages examined. The majority of motoneurons of the dorsolateral nucleus also were positive throughout postnatal development although the percentage of positive motoneurons was slightly higher in males than in females. In contrast, virtually no motoneurons of the spinal nucleus of the bulbocavernosus, located in the medial ventral horn, were positive for CGRP in neonatal rats. CGRP‐like immunoreactivity was delayed in this nucleus until approximately postnatal day 6 in males and day 27 in females. Because these three motoneuronal nuclei are differentially sensitive to early androgen and differ with respect to the timing of several developmental milestones, these observations have implications for the regulation and possible roles of CGRP in developing motor systems.
Cholecystokinin‐, enkephalin‐, and substance P‐like immunoreactivity in the dentate area, hippocampus, and subiculum of the domestic pig
Authors: Holm Ida E. , Geneser Finn A. , Zimmer Jens
Published: January 2005

The distribution of cholecystokinin‐like, enkephalin‐like, and substance P‐like immunoreactivities is described in the dentate area, hippocampus, and subiculum of the domestic pig (Sus scrofa domesticus) as a baseline for future experimental studies. The distributions in the pig are compared with previous observations in other species.

Cholecystokinin‐like immunoreactive nerve cell bodies were intensely stained and present in large numbers in all subfields studied. Cholecystokinin‐like immunoreactive terminals appeared as stained puncta, whereas fibers were only rarely encounterd. The puncta were mainly seen in the dentate molecular layer and dentate granule cell layer, the pyramidal cell layer of the hippocampal regio inferior, stratum moleculare of the hippocampal regio superior, and in the subiculum.

Enkephalin‐like immunoreactive nerve cell bodies were faintly stained and generally present in very small numbers, except for some pyramidal cells in the subicular cell layer. Enkephalin‐like immunoreactive fibers were few in number, whereas stained puncta appeared with variable densities. Puncta of particularly high densities were found in the dentate molecular layer, whereas they appeared of moderate density in the dentate hilus, stratum moleculare of the hippocampal regio superior, and in the subiculum.

Substance P‐like immunoreactive nerve cell bodies were few and very faintly stined. They primarily occurred in the dentate hilus, stratum oriens of the hippocampus, and in the subicular cell layer. Stained fibers were few in number, whereas stained puncta were present in abundant numbers corresponding to the mossy fiber projection in the dentate hilus and the layer of mossy fibers of the hippocampal regio inferior, and in moderate numbers in stratum moleculare of the hippocampal regio superior and in the subiculum.

For all three neuropeptides there were consistent and very characteristic variations in the distribution of immunoreactivity along the septotemporal axis of the hippocampus.

When viewed in a comparative perspective the distribution of enkephalin‐like and substance P‐like terminals in the domestic pig displayed striking differences from the basic pattern observed in other species. This contrasted with the distribution of cholecystokinin‐like neurons and terminals, which resembled more closely these species. © 1993 Wiley‐Liss, Inc.
Organization of the hamster paraventricular hypothalamic nucleus
Authors: Morin L. P. , Blanchard J.
Published: January 2005

The hamster periventricular hypothalamic area has been the focus of functional research concerning photoperiodic time measurement. These studies have relied upon the extensive analysis of rat paraventricular nucleus because there has been a general absence of anatomical description in the hamster. The present work southt to remedy this problem by investigating the structure of the hamster paraventricular nucleus with respect to the localization of cells immunoreactive to vasopressin, oxytocin, or cotricotropin‐releasing factor and of cells projecting to the spinal cord or to vascular sites outside the blood‐brain barrier.

The hamster paraventricular nucludus includes the medial, lateral, and posterior magnocellular divisions, the main parvicellular division, as well as the periventricular area and dorsal cap, which are also parvicellular. The magnocellular divisions are characterized by many large neurons immunoreactive to oxytocin and vasopressin, which are generally absent from the parvicellular divisions. In contrast, corticotrophin‐releasing hormone‐immunoreactive cells are plentiful in most of the parvicellular areas. Spinally projecting cells are found in two rostral areas, one dorsally and a second, more ventral area. More caudally, the two regions merge within the posterior magnocellular division. Cells of the ventral group are frequently immunoreactive for one of the three peptides. Cells identified by peripheral injection of retrograde label are found in the rostral magnocellular divisons but not in the caudal posterior magnocellular division. Areas in which these cells also contain peptide are also described. The features of the hamster paraventricular nucleus are compared to those in the rat and apparent species differences are discussed. © 1993 Wiley‐Liss, Inc.
Organization of the commissural fibers in the adult brain of the locust
Authors: Boyan George , Williams Leslie , Meier Thomas
Published: January 2005

The brain (supraoesophageal ganglion) is the most complex of the segmental ganglia composing the nerve cord of the locusts Schistocerca gregaria and Locusta migratoria. In this paper, we describe the ground plan of the commissures crossing the midline of the brain and propose a nomenclature with the aim of making a complex neuropil more understandable at the level of individual neurons. For developmental and comparative reasons the neuroarchitecture of the brain is related to the neural axis, not to the body axis. We have identified 73 commissural fiber bundles belonging to the adult brain, and these are named according to their location (ventral, dorsal, anterior, posterior, medial) with respect to the central complex as reference point. Reconstructions of identified neurons from intracellular stainings, cobalt backfills, or immunohistochemical studies demonstrate the various configurations in which fibers cross the brain. © 1993 Wiley‐Liss, Inc.
Spiny nonpyramidal neurons in the CA3 region of the rat hippocampus are glutamate‐like immunoreactive and receive convergent mossy fiber input
Authors: Soriano Eduardo , Frotscher Michael
Published: January 2005

There is increasing evidence that the various types of hippocampal nonpyramidal neurons control the principal cells in different ways. In the present study a type of spiny nonpyramidal cell in stratum lucidum of rat hippocampal region CA3 was studied by Golgi impregnation. Three Golgi‐impregnated and gold‐toned neurons of this type were further analyzed by electron microscopy and postembedding immunocytochemistry. The dendrites of these bipolar neurons seemed to be restricted to stratum lucidum and ran parallel with the mossy fibers that terminate in this layer. A characteristic feature of this neuron is the presence of long, thin spines on both cell body and dendrites. Although these dendrites were exposed to a large number of mossy fibers, no thorny excrescences were formed which are characteristic postsynaptic elements of CA3 pyramidal neurons for synaptic contact with the mossy fibers. Semithin sections of Golgi‐impregnated and gold‐toned stratum lucidum cells displayed immunoreactivity of the cell body region for glutamate but not for GABA.

A fine‐structural analysis of gold‐toned sections revealed a large cell body with numerous cytoplasmic organelles and an indented nucleus. Numerous asymmetric synapses were found on dendritic shafts as well as on the long, thin somatic and dendritic spines. Usually, several presynaptic boutons contacted a single spine. The majority of these asymmetric spine synapses were probably of mossy fiber origin, although no giant mossy fiber synapses were formed. The long spines were contacted by much smaller en passant synapses of preterminal axons. In contrast, giant mossy fiber boutons were found presynaptic to dendritic shafts and cell bodies of these cells.

Our morphological analysis of a glutamate‐immunoreactive, GABA‐negative type of non‐pyramidal neuron that receives convergent mossy fiber input suggests that the impulse flow within the “trisynaptic pathway” is more complex than previously assumed. © 1993 Wiley‐Liss, Inc.
New aspects of dopaminergic interplexiform cell organization in the goldfish retina
Authors: Van Haesendonck Eduarda , Marc Robert E. , Missotten Luc
Published: January 2005

Dopaminergic interplexiform cells (DA‐IPCs) in the goldfish retina have been reexamined by light and electron microscopic immunocytochemistry with antisera against dopamine (DA) or tyrosine hydroxylase (TH). Successful immunostaining with a specific anti‐DA antiserum offers further direct support for DA‐IPCs. Anti‐DA immunocytochemistry in combination with [3H]‐DA autoradiography shows 92% colocalization of the two markers, indicating that [3H]‐DA autoradiography is a reliable technique for identification of DA‐IPCs. Incubations with anti‐TH antiserum show that immunoreactive DA‐IPCs have a homogeneous distribution, with an average frequency of 71 ± 8 cells/mm2 in retinas of 14–15 cm long goldfish. Their arrangement is distinctly nonrandom.

Electron microscopy of TH‐immunoreactive cell processes confirms that horizontal cell axons synapse onto DA‐IPCs and adds the following junctional arrangements to the circuit diagram of the DA‐IPC: (1) adjacent serial synapses between DA‐IPCs, external horizontal cells, and putative glycinergic interplexiform cells, (2) junctional appositions between DA‐IPCs and photoreceptor cells, (3) junctional appositions between neighbouring DA‐IPCs, and (4) the “gap junctional complex”, typically consisting of a DA‐IPC process juxtaposed with a gap junction between horizontal cell axons. The gap junction is flanked by clusters of small, round vesicles and groups of electron‐dense structures resembling intermediate filaments. These morphological results support the functional involvement of DA‐IPCs in adaptive retinomotor movements and in horizontal cell gap junction modulation and/or dynamics. They also suggest particular interaction between the dopaminergic and the glycinergic IPC system in the outer plexiform layer of goldfish retina. © 1993 Wiley‐Liss, Inc.
Transient appearance of calbindin‐D28k‐positive neurons in the superior olivary complex of developing rats
Authors: Friauf Eckhard
Published: January 2005

Calbindin‐D28k (CaBP) is a calcium‐binding protein that is prominent in various parts of the mammalian auditory system. In order to shed some light on the possible role of CaBP during ontogeny, when calcium ions play key roles in several processes, the location of CaBP was examined immunocytochemically in the auditory system of the developing rat. This study focuses on the principal nuclei of the superior olivary complex, which show distinct CaBP labeling in the adult. Consistent with previous reports in the rat and other mammals, CaBP immunoreactivity in adults was intense in somata of the medial nucleus of the trapezoid body (MNTB) and in the neuropil (presumably in axons) of the lateral superior olive (LSO), the superior paraolivary nucleus (SPN), and the medial superior olive (MSO). In fetal and neonatal animals, however, the labeling pattern was strikingly different. Around birth, MNTB neurons are immunonegative for CaBP, whereas somata and processes in the LSO, probably neuronal, are heavily labeled at that age. This labeling pattern persists throughout the first week of postnatal life and begins to change at P8, when MNTB neurons become immunopositive for CaBP. During the next 10 days labeling intensity in MNTB neurons increases considerably, and the increase is paralleled by an increase in labeling intensity of the neuropil in the LSO, SPN, and MSO, indicating that the labeled processes in these nuclie may be axons originating from MNTB neurons. Immunoreactivity in LSO cells begins to decline around P8, decays rapidly between P10 and P18, and reaches its adult level around P28, when the CaBP labeling pattern in the whole superior olivary complex is indistinguishable from that in the adult.

The present results show that the development of CaBP immunoreactivity in the rat superior olivary complex is characterized by two reciprocally related processes: as immunoreactivity within MNTB somata and fibers in the SPN, the LSO, and the MSO increases between P8 and about P21, the immunoreactivity in LSO neurons declines. CaBP immunoreactivity in LSO neurons is only transiently present, suggesting a critical period in development during which the control of Ca2+ homeostasis in LSO neurons may be of particular importance. © 1993 Wiley‐Liss, Inc.
Localization of sulfated glycoprotein‐2/clusterin mRNA in the rat brain by in situ hybridization
Authors: Danik M. , Chabot J.‐G. , Hassan‐gonzalez D. , Suh M. , Quirion Rémi
Published: January 2005

Sulfated glycoprotein‐2 (SGP‐2) gene expression seems to be constitutively expressed in a variety of tissues and organs, although levels of expression vary widely from one tissue to the other. SGP‐2, also known as clusterin, has been reported to be expressed in the central nervous system (CNS). Some possible roles for brain SGP‐2 have been postulated. In order to provide a substrate for a better understanding of the functions of this glycoprotein in the CNS, we investigated the detailed anatomical and cellular distribution of SGP‐2 mRNA in the adult rat brain as well as the variation in its cellular expression after excitotoxin lesion. Transcripts for SGP‐2 were found to be distributed throughout the rat CNS, although regional differences in their prevalence were readily observed. The ependymal lining of the ventricles showed the highest level of expression followed by various gray matter areas, some of which contained very intensively labeled cells. These cells were mostly found among several hypothalamic and brainstem nuclei, the habenular complex, as well as in the ventral horn of the spinal cord, which displayed striking hybridization signals over motoneurons. Occasional cells expressing high levels of SGP‐2 transcripts were found in fiber tracts. Highly SGP‐2 mRNA‐positive resting glial cells were mainly located near the glial limitans and blood vessels. Two areas of relatively low constitutive SGP‐2 mRNA expression are shown to produce strong hybridization signals 10 days after the local administration of the excitotoxin kainic acid. This overexpression of SGP‐2 transcripts appears to involve GFAP‐positive cells. Taken together, these results indicate that in the intact adult rat CNS, various cell populations, including neurons, constitutively express SGP‐2 transcripts, whereas in the injured brain, reactive astrocytes become the major producers. © 1993 Wiley‐Liss, Inc.
Evidence that cholinergic axons from the parabrachial region of the brainstem are the exclusive source of nitric oxide in the lateral geniculate nucleus of the cat
Authors: Bickford M. E. , Günlük A. E. , Guido W. , Sherman S. Murray
Published: January 2005

We investigated the source of axons and terminals in the cat's lateral geniculate nucleus that stain positively for NADPH‐diaphorase. The functional significance of such staining is that NADPH‐diaphorase is identical to the enzyme nitric oxide synthetase, and thus it is though to reveal cells and axons that use nitric oxide as a neuromodulator. Within the lateral geniculate and adjacent perigeniculate nuclei, a dense network of axons and terminals is labeled for NADPH‐diaphorase, The pattern of NADPH‐diaphorase staining here is remarkably similar to that of choline acetyltransferase (ChAT) staining, suggesting that the source of these axons and terminals might be the parabrachial region of the brainstem because this provides the major cholinergic input to the lateral geniculate nucleus. In other areas of the brain to which parabrachial axons project, there is also a similar staining pattern for NADPH‐diaphorase and ChAT. Furthermore, the patterns of cell staining within the parabracial region for NADPH‐diaphorase and ChAT are virtually identical. However, the relationship between ChAT and NADPH‐diaphorase staining for the parabrachial region is not a general property of cholinergic neurons. Other cholinergic cells and axons, such as the trochlear nerve, the oculomotor nerve and nucleus, and the parabigeminal nucleus, which all label densely for ChAT, stain poorly or not at all for NADPH‐diaphorase. It is significant that the parabigeminal nucleus, which provides a cholinergic input to the lateral geniculate nucleus, has no cells that label for NADPH‐diaphorase. We used double labeling methods to identify further the source of NADPH‐diaphorase staining in the lateral geniculate nucleus. We found that parabrachial cells co‐localize NADPH‐diaphorase and ChAT. Noradrenergic and serotoninergic cells in the brainstem also innervate the lateral geniculate nucleus, but we found that none of these co‐localize NADPH‐diaphorase. Finally, by combining NADPH‐diaphorase histochemistry with retrograde labeling of cells that project to the lateral geniculate nucleus, we found that the cholinergic cells of the parabrachial region are essentially the sole source of NADPH‐diaphorase in the lateral geniculate nucleus. We thus conclude that cells from the parabrachial region that innervate the lateral geniculate nucleus use both acetylcholine and nitric oxide for neurotransmission, and that this is virtually the only afferent input to this region that uses nitric oxide. © 1993 Wiley‐Liss, Inc.
Representation of the body surface in the gracile, cuneate, and spinal trigeminal nuclei of the little red flying fox (Pteropus scapulatus)
Authors: Martin Russell L.
Published: January 2005

The body surface representation in the gracile, cuneate, and spinal trigeminal nucleil of the little red flying fox (Pteropus scapulatus) was examined. As in other species, it was found that any single cross‐section through all three nuclei contains a representation of most, or all, of the body surface. In the little red flying fox, however, this representation is arranged as a series of dorsolateral to ventromedially oriented bands, within which there are no apparent topographies. These bands are arranged in such a way that the spatial relationships between body regions in the representation do not reflect those at the periphery. © 1993 Wiley‐Liss, Inc.
Laminar distribution of NMDA receptors in cat and monkey visual cortex visualized by [3H]‐MK‐801 binding
Authors: Rosier A. M. , Arckens L. , Orban G. A. , Vandesande F.
Published: January 2005

Glutamate is the major excitatory neurotransmitter of the mammalian central nervous system. Two major classes of glutamate receptors have been reported. The actions of glutamate on its N‐methyl‐D‐aspartate (NMDA)‐type receptor may underlie developmental and adult plasticity as well as neurotoxicity.

The NMDA‐type of glutamate receptor in cat and monkey visual cortex was visualized by means of in vitro receptor autoradiography with the noncompetitive NMDA‐receptor antagonist [3H]‐MK‐801. The kinetics, performed on tissue sections, revealed an apparently single, saturable site with an approximate dissociation constant (KD) of 18.5 nM in cat and 15.9 nM in monkey visual cortex. Autoradiography, performed on frontal sections of cat and monkey visual cortex, revealed a heterogeneous laminar distribution of NMDA receptors.

Cat areas 17,18,19, and the lateral suprasylvian areas exhibited a similar NMDA‐receptor distribution. In these areas, NMDA receptors were most prominent in layer II and the upper part of layer III. In monkey striate cortex, NMDA receptors were primarily concentrated in layers II, upper III, IVc, V, and VI. In monkey secondary visual cortex, [3H]‐MK‐801 labeling was most prominent in layers II, V, and VI; whereas in the temporal visual areas included in this study layer II displayed the heaviest receptor labeling.

In neither cat nor monkey could we observe significant differences in NMDA‐receptor distribution between different retinotopic subdivisions within a single visual area. Neither did we detect any periodic changes in NMDA‐receptor distribution that would correspond to the compartments defined by cytochrome‐oxidase in monkey V1 and V2. © 1993 Wiley‐Liss, Inc.
Spinal termination patterns of canine identified A‐δ and C spermatic polymodal receptors traced by intracellular labeling with Phaseolus vulgaris‐leucoagglutinin
Authors: Mizumura Kazue , Sugiura Yasuo , Kumazawa Takao
Published: January 2005

The spinal projection patterns of spermatic polymodal receptors were studied by intracellular labeling of functionally identified canine dorsal root ganglion (DRG) neurons with Phaseolus vulgaris‐leucoagglutinin (PHA‐L). The processes of 2 C‐fiber and 1 A‐δ‐fiber spermatic polymodal receptor neurons were labeled well enough to trace their central terminations. The labeled C‐fiber DRG neurons were of medium size (mean diameter 36.8 and 40.7 μm). On entering the spinal cord, axons of the C‐polymodal receptors divided into rostral and caudal main branches that extended over 3 spinal segments (20 and 25 mm, respectively), and issued a total of 16 and 15 collaterals, respectively. The majority of collaterals ran in or along the lateral surface, but both neurons had 1 or 2 collaterals or terminal branches running through the middle, or along the medial, surface of the dorsal horn. Terminal swellings and en passant enlargements were observed mainly in laminae I, V, and VII. Some C‐fiber terminations appeared in lamina II and the adjacent lateral column. The A‐δ polymodal receptor had a termination pattern similar to that of the C‐fiber units with the exception of a shorter distance over which its 13 identified collaterals were issued (10 mm), and continuation of the rostral main branch into Lissauer's tract (traced for 3.6 mm) after all branches appeared. Two terminal branches were found running just above the central canal in another A‐δ neuron in which termination could be only partially traced. The density of terminals of spermatic thin afferents was lower and their rostrocaudal spread was more extensive than those reported in cutaneous C‐polymodal nociceptors. These results suggest that spermatic afferents are organized to exert a diffuse and wide‐spreading influence on the spinal neurons. © 1993 Wiley‐Liss, Inc.
Immunocytochemical evidence of well‐developed dopaminergic and noradrenergic innervations in the frontal cerebral cortex of human fetuses at midgestation
Authors: Verney Catherine , Milosevic Ana , Alvarez Chantal , Berger Brigitte
Published: January 2005

The catecholaminergic (CA) innervation of the frontal lobe was visualized in 20‐ to 24‐week‐old human fetuses with immunocytochemical techniques, by use of antibodies raised against three synthetic enzymes of the CA pathway, tyrosine‐hydroxylase (TH), dopamine‐β‐hydroxylase (DBH), and phenylethanolamine‐N‐methyltransferase (PNMT). DBH‐like immunoreactivity (IR) was probably labeling the noradrenergic (NA) fibers and terminals in the cerebral cortex since no PNMT‐IR fibers were detected. In double‐labeling TH‐DBH experiments, 92–95% of the DBH‐IR afferents were not labeled with TH antibodies, indicating that TH‐like immunoreactivity (TH‐IR) was found primarily in dopaminergic (DA) fibers. Although cortical layering had not yet occurred at this stage, the widespread CA innervation observed in the different areas and layers of the fetal frontal cortex was comparable to that previously described in the adult (Gaspar, Berger, Febvret, Vigny, and Henry: J. Comp. Neurol. 279:249–271, '89). At midgestation, the distribution of CA innervation was region and laminar specific: (1) The densest dopaminergic innervation in the cerebral cortex was located caudal to the genu of the corpus callosum: TH‐IR fibers were abundant throughout all layers, from the medial telencephalon (future cingulate) to the dorsal areas (presumed motor cortices) and the lateral insular areas; (2) TH‐IR fibers were less dense in the rostral prefrontal cortical anlage; (3) DBH‐IR noradrenergic afferents were less numerous than the dopaminergic ones in all the cortical areas studied; (4) in all areas, the highest amount of TH and DBH‐IR terminals was found in the upper subplate and in the lower part of the cortical plate, followed by the molecular layer and the intermediate zone. The deep subplate exhibited a lower number of positive fibers but contained TH‐IR cell bodies. The presence of dense CA innervation in the immature cortical anlage of the human frontal lobe does not exclude a reorganization of DA and NA innervations within the different cortical layers and areas during the protracted pre‐ and postnatal period of development. © 1993 Wiley‐Liss, Inc.
Cytoarchitecture, fiber connections, and ultrastructure of the nucleus pretectalis superficialis pars magnocellularis (PSm) in carp
Authors: Yoshimoto Masami , Ito Hironobu
Published: January 2005

The cytoarchitecture, fiber connections, and ultrastructure of the nucleus pretectalis superficialis pars magnocellularis (PSm) were studied in cypriniform teleosts (Cyprinus carpio). The PSm is an oval nucleus in the pretectum. Medium‐sized cells and synaptic glomeruli are the main components of the nucleus. A lesser number of small cells are also present. Most of the medium‐sized cells form one or two cell layers on the periphery of the nucleus, and some cells are scattered among synaptic glomeruli in the nucleus. Cell bodies in the peripheral cell layer are pyriform and sprout a thick dendrite directed inward. The dendrite gives off fine dendritic branches, which are postsynaptic elements in synaptic glomeruli.

The PSm projects to the ipsilateral corpus mamillare (CM) and sends collaterals to the ipsilateral nucleus lateralis valvulae (NLV). Axons of the PSm neurons have terminals with many varicosities in the CM, and collaterals in the NLV have cup‐shaped terminals around the cell bodies of the NLV neurons. Following horseradish peroxidase (HRP) injections into the PSm, HRP‐labeled cells are found ipsilaterally in the optic tectum, the nucleus tractus rotundus of Schnitzlein, and the nucleus ruber of Goldstein. The tecto‐PSm projections are topographically organized. The rostral optic tectum projects mainly to the rostral portion of the PSm, and the caudal tectum projects to the caudal portion of the PSm. The ventral tectum sends fibers mainly to the ventral part of the PSm. The dorsomedial tectum projects to the medial part of the PSm, and the dorsolateral tectum projects to the lateral part of the PSm. Tectal projection neurons to the PSm are of only one type. The tectal cell body is pyriform and is situated in the superficial part of the ipsilateral stratum periventriculare (SPV). The tectal neurons have a long perpendicular dendrite, which branches out in the stratum opticum (SO). An axon emerges from the branching site in the SO. Judging from the dendritic branching pattern of the tectal projection neurons, we concluded that the PSm receives visual information from the optic tectum. © 1993 Wiley‐Liss, Inc.
Patterns of projections from the pontine nuclei and the nucleus reticularis tegmenti pontis to the posterior vermis in the rhesus monkey: A study using retrograde tracers
Authors: Thielert C.‐D. , Thier P.
Published: January 2005

In an attempt to estimate the relative importance of the various afferent systems impinging on the oculomotor regions of the posterior cerebellar vermis of rhesus monkeys in quantitative terms, we made small injections of the retrograde tracers fast blue, fluorogold, and cholera toxin into different parts of a region of the posterior vermis, spanning lobuli VI through VIII. We found that the vast majority of cells retrogradely labeled by injections of lobulus VII and its vicinity lay in the pontine nuclei (PN), the nucleus reticularis tegmenti pontis (NRTP), and subnuclei a and b of the medial accessory olive. The remaining retrogradely labeled cells were distributed among a number of other brainstem nuclei or regions including the paramedian pontine reticular formation (PPRF).

A quantitative analysis showed that the projection from the NRTP to the posterior vermis was focused on lobulus VII. While the projection from the PN as a whole demonstrated a preference for the more caudal parts of the posterior vermis, a closer look at the different regions of the PN revealed that cells located in the dorsal parts of the PN showed the same preference for lobulus VII as cells in the NRTP.

The dorsal PN are a major gateway for cortical input to the cerebellum, related to visual processing and visually guided eye movements. Conversely, the NRTP, likewise involved in visually guided eye movements, is much more dependent on subcortical afferents. The observed convergence of input derived from the dorsal PN and the NRTP in oculomotor lobulus VII therefore suggests that a major function of this part of the vermis might be the integration of cortical and subcortical signals important for visually guided eye movements. © 1993 Wiley‐Liss,Inc.
Distribution of GABAergic synaptic terminals on the dendrites of locust spiking local interneurones
Authors: Leitch Beulah , Laurent Gilles
Published: January 2005

Double‐labelling and electron microscopy were used to assess the distribution of GABAergic synapses made onto the neurites of spiking local interneurones in the locust. The aims were to determine the sites of inputs mediating inhibition of the spiking local interneurones and to ascertain the relative abundance of such inputs. This information should allow us to understand better the integrative properties of these spiking local interneurones and the role of inhibition in shaping their receptive field properties or in fine tuning their spike‐mediated outputs.

Spiking interneurones in a midline population were labelled by intracellular injection of horseradish peroxidase after physiological characterisation. Colloidal gold immunocytochemistry was then used on ultrathin sections of these neurones with a polyclonal antibody raised against GABA. Most GABAergic (inhibitory) input synapses onto the interneurones are made on their ventral neurites, which also receive afferent (excitatory) inputs. These inhibitory inputs to the ventral neurites constitute 43% of the identifiable synapses. Relatively few GABAergic inputs were found onto the dorsal neurites, which are predominantly the sites of output synapses from these interneurones. These results suggest that much synaptic integration takes place in the ventral field of branches and that GABA‐mediated presynaptic inhibitory control of spike‐mediated outputs from the dorsal neurites is unlikely to occur. © 1993 Wiley‐Liss, Inc.
Ferritin, transferrin, and iron in selected regions of the adult and aged rat brain
Authors: Benkovic Stanley A. , Connor James R.
Published: January 2005

Iron is necessary for normal neural function but it must be stringently regulated to avoid iron‐induced oxidative injury. The regulation of systeimic iron is through the proteins transferrin (iron mobilization) and ferritin (iron sequestration). This study examines the cellular and regional distribution of iron and the iron‐related proteins ferritin and transferrin in selected regions of the adult and aged rat brain. This information is a necessary prerequisite to understanding the mechanism by which iron homeostasis is maintained in the brain. The predominant cell type containing ferritin, transferrin, and iron throughout the brain at all ages is the oligodendrocyte. Neurons in most brain regions contain granular iron deposits which become more apparent with age. Ferritin and iron are also present in microglial cells in all brain regions, but are particularly abundant in the hippocampus. These latter cells visibly increase in number in all brain regions as the animal approaches senescence. Another area in which immunostaining is notable is surrounding the III ventricle, where transferrin is found in the choroid plexus and ependyma and ferritin and iron are present in tanycytes. The results of this study indicate an important role for neuroglia in the regulation of iron in the brain and also implies that a transport system may exist for the transfer of iron between the brain and cerebrospinal fluid. In the normal rodent brain, the principal cell of iron regulation is the oligodendrocyte; however, the role of microglial cells in the sequestration and detoxification of iron may be significant, particularly as the animal ages. With age there is an increase in stainable iron in neurons without a concomitant increase in neuronal ferritin immunostaining, suggesting a ferritin independent accumulation of neuronal iron with age. © 1993 Wiley‐Liss, Inc.