bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunohistological localization of tenascin‐c in the developing and regenerating retinotectal system of two amphibian species
Authors: Becker Thomas , Becker Catherina G. , Niemann Ulrike , Naujoks‐Manteuffel Christiane , Bartsch Udo , Schachner Melitta , Roth Gerhard 
Published: January 2005

AbstractThe expression pattern of the extracellular matrix molecule tenascin‐C was investigated in the retinotectal system of the frog Discoglossus pictus and the salamander Pleurodeles waltl during development and optic nerve regeneration in the adult. In both species, the retina was devoid of tenascin‐C immunoreactivity at all ages studied. During development, tenascin‐C was distributed in a gradient in the optic nerve, with the highest immunoreactivity in the eye near part of the optic nerve. The myelin‐associated glycoprotein was distributed in a gradient with opposite polarity. In Discoglossus, but not Pleurodeles, tenascin‐C was detected in the anterior chiasm. In the tectum of both species, tenascin‐C was observed in deep cellular and fiber layers but not in the layers receiving optic fibers or proliferative zones. The distribution patterns of tenascin‐C were the same during development and in the adult, except for a disappearance of the molecule from the intraocular part of the optic nerve. After lesioning the optic nerve of adult animals, tenascin‐C was strongly reexpressed in the intraocular part of the optic nerve but was only weakly upregulated in the distal optic nerve stump. In contrast, a chondroitin sulfate epitope was strongly upregulated in the distal optic nerve stump.These observations suggest that during development, tenascin‐C serves as an attenuating barrier for myelinating cells in the optic nerve and contributes to the guidance of growing retinal ganglion cell axons. Due to its sustained expression in the adult, tenascin‐C may have similar functions during regeneration of the lesioned adult retinotectal system. © 1995 Wiley‐Liss, Inc.
Brain‐derived neurotrophic factor mRNA is expressed in the developing taste bud‐bearing tongue papillae of rat
Authors: Nosrat C. A. , Olson L. 
Published: January 2005

AbstractBrain‐derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are expressed in many areas of the nervous system and its target tissues. Using in situ hybridization we have investigated the possible presence of NGF mRNA and BDNF mRNA in the developing fungiform and circumvallate papillae of the rat tongue. BDNF mRNA is present in the epithelium of the developing fungiform papillae in E15, E16, and E17 rat embryos with peak concentration at E16. It starts to diminish after E17 and is almost absent at E21. There is a specific temporospatial change in the expression of BDNF mRNA in developing circumvallate papillae. It is expressed in the epithelium of the superior and posterior surfaces of the papillae at E15, E16, and E17. Already at E17 the BDNF mRNA labeling has started to decrease in the superior epithelium. At E19 and E21, BDNF mRNA is exclusively present in the epithelium of the inner and outer walls of the trench, surrounding the papilla at the posterior and lateral surfaces where the taste buds are located later in life. BDNF mRNA was also detected in the developing palatal taste buds. NGF mRNA was below detection level in the developing papillae. The highly localized expression of BDNF mRNA in areas where taste buds are to be formed suggests that BDNF may be one crucial factor in the formation of the epithelial innervation prior to taste bud formation. It might also participate in the formation and/or maintenance of the papillary and/or taste bud innervation apparatus. We conclude that the neurotrophin BDNF is expressed in early development of taste bud‐bearing papillae in the rat tongue in a temporally and spatially controlled manner, presumably to act as a target‐derived chemoat tractant for the early nerve fibers. © 1995 Wiley‐Liss, Inc.
Two histological markers reveal a similar photoperiodic difference in the volume of the high vocal center in male European starlings
Authors: Bernard Daniel J. , Ball Gregory F. 
Published: January 2005

AbstractMost studies of seasonal changes in the avian song control system have used Nissl stains to characterize the nuclei. More recent work has indicated that changes in nucleus volume evident in Nissl‐stained tissue are not always apparent when investigated with other histochemical criteria. In this experiment, we used two different markers (Nissl stain and α2‐adrenergic receptor autoradiography) to characterize changes in the song system of European starlings (Sturnus vulgaris). Fluctuating levels of circulating testosterone (T) appear to be causally related to seasonal changes in the song system. Therefore, we used photoperiod manipulations to place male starlings into different physiological conditions. Photosensitive male starlings were placed on 11L:13D or 16L:8D photoperiods for at least 5 months. Birds on 11L:13D have enlarged gonads and circulating T. In contrast, starlings maintained on 16L:8D initially show marked gonadal growth. However, after about 6–8 weeks the birds are photorefractory (i.e., the gonads are regressed and T falls to undetectable levels). The volume of the high vocal center (HVC) was 44% larger in the 11L:13D than in 16L:8D birds in Nissl‐stained tissue. The density of α2‐adrenergic receptors as determined by in vitro receptor autoradiography with [3H]p‐amino‐lonidine (PAC) is higher in HVC than in the surrounding neostriatum, clearly delineating the boundaries of the nucleus. We reconstructed the volume of HVC using PAC autoradiography on adjacent sections. The results were identical to those from the Nissl‐stained tissue. Thus, two histochemical markers indicate a photoperiodic difference in HVC volume of male starlings. © 1995 Wiley‐Liss, Inc.
Morphology of thalamocortical neurons projecting to the primary somatosensory cortex and their relationship to spinothalamic terminals in the squirrel monkey
Authors: Shi Ting , Apkarian A. Vania 
Published: January 2005

AbstractThis study examined the morphology of thalamocortical neurons projecting to the primary somatosensory cortex (SI; hand region of areas 3a, 3b, 1, and 2) and their relationship to the spinothalamic (STT) terminals in the squirrel monkey. Retrogradely labeled thalamocortical neurons were intracellularly filled with Lucifer yellow (LY), and the STT terminals were anterogradely labeled with biotinylated dextran. Both filled neurons and labeled terminals were differentially visualized in the same field by a dual immunocytochemical staining method. SI‐projecting neurons appeared at the light level to be in contact with STT terminal boutons in the ventroposterior lateral (VPL), ventroposterior inferior (VPI), and centrolateral (CL) nuclei and the posterior complex (PO). The analyses of the neuronal morphology revealed that somatic and dendritic morphologies of SI‐projecting neurons in these thalamic nuclei, as well as in the anterior pulvinlar (Pub), centromedial (CM), and ventrolateral (VL) nuclei, were generally comparable with some exceptions: VPL neurons had the largest soma sizes, the most primary dendrites, and the longest total dendritic length among all neurons studied; VPI neurons had the smallest soma sizes; VPL SI‐projecting neurons were different from those in VPI in their soma sizes, shape factors, and orientations; in VPL the cells projecting to the superficial layers of SI were smaller than those projecting to the deeper layers, but in VPI the two groups of neurons were similar in soma sizes. In general, the SI‐projecting neurons in VPL, VPI, and CL were similar in their dendritic morphologies and branching patterns, and varied from those in Pub, PO, CM, and VL. © 1995 Wiley‐Liss, Inc.
Dopamine receptor mRNA expression patterns by opioid peptide cells in the nucleus accumbens of the rat: A double in situ hybridization study
Authors: Curran Eileen J. , Watson Stanley J. 
Published: January 2005

AbstractColocalization of proenkephalin and prodynorphin mRNAs with each other as well as with D1, D2, and D3 dopamine receptor mRNAs was analyzed in the nucleus accumbens of the rat. Distinct combinations were detected in the rostral pole, core, and shell subdivisions of the nucleus accumbens. Proenkephalin and prodynorphin mRNAs were principally localized in separate cells in the core. All detectable prodynor cells in the core expressed D1 mRNA but not D2 mRNA. Conversely, approximately 95% of the proenkephalin‐positive cells in this region expressed D2 mRNA but not D1 mRNA. This pattern was identical to that observed in the caudate putamen. In the rostral pole and the shell, embedded in a background of this “typical” colocalization pattern, clusters of cells expressing a distinct configuration were found. In these clusters, proenkephalin‐positive cells expressed both prodynorphin and D1 mRNAs, but they did not express D2 mRNA.D3 and prodynorphin mRNAs were colocalized in “limbic” striatal areas, including the ventromedial caudate putamen, the rostral pole, and the medial shell. In contrast, D3 mRNA was not detected in any proenkephalin‐positive cells. Together with the prodynorphin/D1 data, this suggests that a subset of prodynorphin cells expresses both D1 and D3 mRNAs.It is concluded that (1) clusters of cells that coexpress proenkephalin, prodynorphin, and D1 mRNAs overlap extensively with previously defined cytoarchitectural cell clusters in the nucleus accumbens and (2) a subset of the prodynorphin cells in the ventromedial caudate putamen and the nucleus accumbens contains both D1 and D3 mRNAs. © 1995 Wiley‐Liss, Inc.
Topographical organization in the early postnatal projection: A carbocyanine dye and 3‐D computer reconstruction study in the rat
Authors: Leergaard Trygve B. , Lakke Egbert A. J. F. , Bjaalie Jan G. 
Published: January 2005

AbstractWe have explored basic rules guiding the early development of topographically organized projections, employing the rat corticopontine projection as a model system. Using anterograde in vivo tracing with 1,1′, dioctadecyl‐3,3,3′,3′ ‐tetramethylindocarbocyanine perchiorate (DiI), we studied the distribution of labelled fibers in the pontine nuclei in relation to cortical site of origin during the first postnatal week.Labelled corticopontine fibers enter the pontine nuclei in distinct, sharply defined zones. The putative terminal fibers typically occupy lamella‐like subspaces. Related to changes in cortical site of origin, we describe mediolateral, internal to external, and caudorostral distribution gradients in the pontine nuclei. Fibers originating in the anterolateral cortex occupy an internal central core, while implantations at increasing distance from the anterolateral cortex produce (1) more externally located lamellae, and (2) a caudal to rostral shift in fiber location. Previous investigations have shown that pontocerebellar neurons migrate into the ventral pons in a temporal sequence (Altman and Bayer [1987] J. Comp. Neurol. 257:529). The earliest arriving neurons occupy the central core and later arriving neurons settle in more externally and rostrally located subspaces. We hypothesize that the earliest arriving corticopon tine fibers grow into the then only available zone of pontocerebellar neurons (central core), attracted by a diffusible chemotropic cue. Later arriving fibers grow into correspondingly later and more externally and rostrally located contingents of pontocerebellar neurons. Thus, we propose that the topographical organization in the early postnatal corticopontine projections determined by simple temporal and spatial gradients operative within source cerebra cortex and target region (pontine nuclei). © 1995 Wiley‐Liss, Inc.
Morphological diversity and glutamate immunoreactivity of retinal terminals in the suprachiasmatic nucleus of the cat
Authors: Chen Boqing , Pourcho Roberta G. 
Published: January 2005

AbstractAlthough the cat visual system has been the subject of intensive investigation, little attention has been given to the morphological features of ganglion cell projections to the suprachiasmatic nucleus. The present study has utilized anterograde transport of horseradish peroxidase and wheat germ agglutinin–conjugated horseradish peroxidase to label ganglion cell terminals in the cat suprachiasmatic nucleus. Visualization of the reaction product was facilitated through the use of gold‐substituted silver intensification. Ganglion cell terminals were found to be morphologically diverse, making both asymmetric and symmetric contacts with postsynaptic processes. Synaptic vesicles were either scattered or densely packed, sometimes forming paracrystalline arrays. In contrast to other retinorecipient areas in which ganglion cell terminals have, been characterized by the presence of lightly staining mitochondria, many of the retinal terminals in the suprachiasmatic nucleus were seen to contain darkly stained mitochondria. Postembedding antiglutamate immunocytochemistry was used to evaluate the level of endogenous glutamate in these ganglion cell terminals. Although morphologically diverse, all of the retinal terminals in the suprachiasmatic nucleus were glutamate positive, consistent with the postulated role of glutamate as the neurotransmitter of retinal ganglion cells. © 1995 Wiley‐Liss, Inc.
Oculomotor control in calliphorid flies: Head movements during activation and inhibition of neck motor neurons corroborate neuroanatomical predictions
Authors: Gilbert Cole , Gronenberg Wulfila , Strausfeld Nicholas J. 
Published: January 2005

AbstractIn tethered flying flies, moving contrast gratings or small spots elicit head movements which are suited to track retinal images moving at velocities up to 3,000°/sec (about 50 Hz contrast frequency for gratings of spatial wavelength 15°). To investigate the neural basis of these movements we have combined videomicroscopy with electrophysiological stimulation and recording to demonstrate that excitation of prothoracic motor neurons projecting in the anterodorsal (ADN) and frontal nerves (FN), respectively, generates the yaw and roll head movements measured behaviorally. Electrical stimulation of the ADN produces head yaw. The visual stimuli which excite the two ADN motor neurons (ADN MNs) are horizontal motion of gratings or spots moving clockwise around the yaw axis in the case of the right ADN (counterclockwise for left ADN). Activity is inhibited by motion in the opposite direction. Spatial sensitivity varies in the yaw plane with a maximum between 0° and 40° ipsilaterally, but both excitation and inhibition are elicited out to 80° in the ipsilateral and contralateral fields. ADN MNs respond to contrast frequencies up to 15–20 Hz, with a peak around 2–4 Hz forgrating motion in the excitatory or inhibitory directions. Electrical stimulation of the FN primarily elicits roll down to the ipsilateral side. The one FN MN consistently driven by visual stimulation is excited by downward motion and inhibited by upward motion at 80° azimuth in the ipsilateral visual field. At −80° contralateral, visual motion has the opposite effect: Upward is excitatory and downward is inhibitory. The FN MN is tuned to contrast frequencies in the same range as the ADN MNs, with peak sensitivity around 4 Hz. The functional organization of inputs to the ADN and FN is discussed with respect to identified visual interneurons and parallel pathways controlling motor output. © 1995 Wiley‐Liss, Inc.
Oculomotor control in calliphorid flies: GABAergic organization in heterolateral inhibitory pathways
Authors: Strausfeld Nicholas J. , Kong Alberta , Milde Jürgen J. , Gilbert Cole , Ramaiah Lila 
Published: January 2005

AbstractIn calliphorid Diptera, motor neurons mediating visually evoked head movements can be excited or inhibited by visual stimuli, depending on the directionality of the stimulus and whether it is in the ipsi‐ or contralateral visual field. The level at which inhibition occurs is of special interest because binocular activation of homolateral tangential neurons in the lobula plate demonstrates that excitatory interaction must occur between the left and right optic lobes. Recordings and dye fillings demonstrate a variety of motion‐sensitive heterolateral pathways between the lobula plates, or between them and contralateral deutocerebral neuropil, which provides descending pathways to neck motor centers. The profiles of heterolateral tangential cells correspond to neurons stained by an antibody against γ‐aminobutyric acid (GABA). Other GABA‐immunoreactive interneurons linking each side of the brain correspond to uniquely identified motion‐sensitive neurons linking the deutocerebra. Additional inhibitory pathways include heterolateral GABAergic descending and ascending neurons, as well as heterolateral GABAergic neurons in the thoracic ganglia. The functional significance of heterolateral GABAergic pathways was tested surgically by making selective microlesions and monitoring the oculoniotor output. The results demonstrate an important new attribute of theinsect visual system. Although lesions can initially abolish an excitatory or inhibitory response, this response is reestablished through alternative pathways that provide inhibitory and excitatory information to the same motor neurons. © 1995 Wiley‐Liss, Inc.
The guidance molecule Semaphorin III is expressed in regions of spinal cord and periphery avoided by growing sensory axons
Authors: Wright D. E. , White F. A. , Gerfen R. W. , Silos‐Santiago I. , Snider William 
Published: January 2005

AbstractThe protein collapsin was purified from chick brain on the basis of its ability to inhibit sensory neuron growth cones, implicating this molecule in sensory axon guidance (Luo et al. [1993] Cell 75:217–227). To examine the relationship between collapsin and sensory axon growth, we examined the pattern of mRNA expression of collapsin's mammalian paralogue, Semaphorin III (Sema III), and compared it to dorsal root ganglion (DRG) axon pathways in the developing rat embryo. Centrally, DRG axons enter the spinal cord by embryonic (E) 11 and branch into the gray matter by E 15 in brachial and thoracic regions. Laminar specific targets are reached by E17. Between E13 and E17, Sema III mRNA is expressed at high levels in the entire ventral half of the spinal cord except the floor plate. This pattern suggests that Sema III may inhibit non‐proprioceptive sensory axons from penetrating the ventral spinal cord. Peripherally, sensory axons have entered the anterior sclerotome by E 11 at all rostrocaudal levels. At this age, Sema III mRNA is already expressed in the dermamyotome and ventral aspect of the posterior sclerotome, areas which axons pass between but do not penetrate en route to their peripheral targets. From E12 to E15, the axons lengthen and branch into smaller fascicles which extend toward peripheral targets. During this time, Sema III mRNA isexpressed by many mesodermal structures surrounding the axon fascicles, with highest levels observed in the dermamyotome, perinotochordal mesenchyme, pelvic girdle, and limb. As development proceeds, Sema III mRNA expression is quickly downregulated before disappear ing by birth. Taken together, our results demonstrate that the gene for Sema III is expressed in central and peripheral regions which are avoided by growing DRG axons. These findings are consistent with the idea tha Sema III inhibits growth and branching of axons into inappropri ate areas during development. © 1995 Wiley‐Liss, Inc.
Presence or absence of TrKA protein distinguishes subsets of small sensory neurons with unique cytochemical characteristics and dorsal horn projections
Authors: Molliver Derek C. , Radeke Monte J. , Feinstein Stuart C. , Snider William D. 
Published: January 2005

AbstractInvestigations into the biological actions of nerve growth factor (NGF) have shown that dorsal root ganglion (DRG) neurons subserving nociception require NGF for survival and maintenance of phenotype. This discovery suggests that the signaling NGF receptor, TrkA, can be used as a marker for nociceptive neurons. In this study, we have used antibodies to TrkA, in conjunction with cell biological markers that show a restricted distribution in the DRG, to further characterize subsets of DRG neurons that are dependent upon NGF. Staining for TrkA labeled small and medium‐sized neurons that composed 47% of all neurons in thoracic ganglia. Double‐labeling with antibodies to the high molecular weight neurofilament protein (NFH), a marker for neurons with myelinated axons, demonstrated that TrkA staining is found in only a small subset of myelinated neurons. Surprisingly, many DRG neurons were not labeled by either TrkA or NFH. These neurons had small soma areas, contained the intermediate filament protein peripherin, and were labeled by the lectin BSI, identifying them as neurons likely to have unmyelinated axons. In addition, small TrkA–negative neurons were extensively labeled by antibodies to the intermediate filament protein γ‐internexin, the delta isoform of protein kinase C, and by the BSI isolectin BSI‐B4. In order to assess the potential functions of TrkA–negative small neurons, we examined their projections to the dorsal horn of the spinal cord. TrkA–immunoreactivity in the spinal cord was restricted to lamina I and the outer region of lamina II (II0), similar to staining for calcitonin gene‐related peptide. In contrast, the central projections of TrkA–negative neurons, as visualized by BSI‐B4 staining, were particularly dense in lamina IIi. Our results suggest that TrkA‐expressing and non‐TrkA‐expressing small neurons compose functionally distinct populations of DRG neurons. © 1995 Wiley‐Liss, Inc.
Retinal neurons and vessels are not fractal but space‐filling
Authors: Panico Joseph , Sterling Peter 
Published: January 2005

AbstractMany branched patterns in nature are hypothesized to be fractal, i. e., statistically self‐ similar across a range of scales. We tested this hypothesis on the two‐dimensional arbors of retinal neurons and blood vessels. First, we measured fractalness on synthetic fractal and nonfractal patterns. The synthetic fractal patterns exhibited self‐similarity over a decade of scale, but the nonfractal “controls” showed hardly any self‐similarity. Neuronal and vascular patterns showed no greater self‐similarity than the controls. Second, we manipulated a synthetic fractal pattern to remove its self‐similarity and found this to be reflected in a loss of measured fractalness. The same manipulation of the nonfractal control and also of the neural and vascular patterns did not alter their measured fractalness. Third, we “grew” patterns of branched line segments according to a variety of nonfractal algorithms. These patterns were, if anything slightly more fractal than the neural and vascular patterns. We conclude that the biological patterns studied here are not fractal. Finally, we measured extended versions of these patterns: a contiguous array of homotypic neuron arbors and a vascular pattern with a high degree of total detail. These patterns showed a “fractal dimension” of 2, which implies that down to some cut‐off scale they fill space completely. Thus, neural and vascular patterns might best be described as quasi‐regular lattices. © 1995 Wiley‐Liss, Inc.