bluuebunny/crossref_metadata_2025_split huggingface dataset:
Claustrin, an antiadhesive neural keratan sulfate proteoglycan, is structurally related to MAP1B
Authors: Burg Michael A. , Cole Gregory J. 
Published: January 2005

AbstractOur laboratory has recently identified a keratan sulfate proteoglycan (KSPG), named claustrin, that inhibits neural cell adhesion and neurite outgrowth in the chick nervous system. Antisera prepared against claustrin were used to screen a cDNA expression library from embryonic day 9 chick brain. Initial characterization of positive cDNAs revealed a high degree of homology to the mouse MAP1B gene, although these cDNAs represent a 5′ truncated fragment of MAP1B. Protein sequencing of three peptides derived from a tryptic digest of purified, keratanase‐treated claustrin also revealed strong homology to MAP1B, and confirmed the authenticity of the 3.4 kb claustrin cDNA. To further determine the relationship between these two proteins, we used antibodies against MAP1B and KSPGs in immunoblotting and immunohistochemical studies. These studies demonstrated cross‐reactivity between MAP1B and claustrin antibodies, and that monoclonal antibodies to cartilage keratan sulfate react with MAP1B in rat nervous tissue, and with claustrin in the chick nervous system. In addition, keratanase treatment of a taxol microtubule fraction from chick or rat brain eliminated MAP1B, as detected by immunoblotting with the MAP5 monoclonal antibody. These results suggest that MAP1B and claustrin are highly related, if not identical, proteins. 1994 John Wiley & Sons, Inc.
Central projection of auditory receptors in the prothoracic ganglion of the bushcricket Psorodonotus illyricus (tettigoniidae): Computer‐aided analysis of the end branch pattern
Authors: Ebendt Ruettger , Friedel Joerg , Kalmring Klaus 
Published: January 2005

AbstractThe projection patterns of morphologically and functionally identified auditory and auditory‐vibratory receptor cells of receptor organs (the crista acustica and the intermediate organ) in the foreleg of the tettigoniid Psorodonotus illyricus, were investigated with combined recording and staining techniques, and subsequent histological examination and morphometric measurements. With the application of a computer program (AutoCAD), three‐dimensional reconstructions of the axon end branches of receptor cells within the neuropile of the anterior Ring Tract (aRT) were made, in order to determine, the entire shape of each, the pattern and density of the end branches, and the positions of the target areas within the auditory neuropile. Clear differences for different functional types of receptors were found. 1994 John Wiley & Sons, Inc.
Galanin and vasoactive intestinal peptide messenger RNAs increase following axotomy of adult sympathetic neurons
Authors: Mohney Robert P. , Siegel Ruth E. , Zigmond Richard E. 
Published: January 2005

AbstractThe adult rat superior cervical ganglion (SSG) contains low levels of galanin‐ and vasoactive intestinal peptide‐(VIP) like immunoreactivity, with very few immuno‐stained principal neurons. Immunoreactivity for both neuropeptides increases in these neurons after explanation or postganglionic axotomy in vivo. Northern blot analysis had demonstrated concomitant increases in mRNAs encoding these peptides. To localize cells in axotomized ganglia which increase their expression of these mRNAs, we performed in situ hybridization studies. In control SCG, only a few principal neurons contained mRNA for either galanin or VIP. After 48 h in organ culture, galanin mRNA was expressed in the majority of principal neurons. At 48 h after in vivo axotomy of both postganglionic trunks of the SCG, the internal and external carotid nerves, the distribution and number of neurons expressing galanin mRNA increased similarly to that seen in culture. Lesioning either trunk alone produced increases in galanin mRNA localized to those regions of the ganglion containing neurons that project into the lesioned trunk. Transection of the predominantly preganglionic cervical sympathetic trunk increased galanin mRNA expression in a small population of neurons that nerve trunk. The distributions of these labeled neurons, together with previous neuroanatomical studies, suggests that they had been axotomised by the lesions. Similar studies examining VIP mRNA expression demonstrated that although considerably fewer VIP mRNA expressing neurons than galanin mRNA expressing neurons were present after axotomy, the distribution of neuropeptide mRNA‐positive cells were similar in both cases. These observations suggest that increases in the peptide galanin and VIP after nerve transection result from changes in the levels of their mRNAs in those neurons that have been axotomized. 1994 John Wiley & Sons, Inc.
Regulation of vasoactive intestinal peptide expression in sympathetic neurons in culture and after axotomy: The role of cholinergic differentiation factor/leukemia inhibitory factor
Authors: Sun Yi , Rao Mahendra S. , Zigmond Richard E. , Landis Story C. 
Published: January 2005

AbstractVasoactive intestinal peptide (VIP) expression increases in sympathetic neurons when they are grown in dissociated cell or explant cultures and when they are axotomizedin vivo. In dissociated cell culture, the magnitude of the VIP increase was reduced when nonneuronal cells were removed and medium conditioned by ganglionic nonneuronal cells increased VIP in neuron‐enriched cultures. Antiserum Against cholinergic differentiation factor (also leukemia inhibitory factor; CDF/LIF), but not against ciliary neurotrophic factor, immunoprecipitated this activity. Medium conditioned by sympathetic ganglion explants also contained a VIP‐stimulatory molecule that was immunoprecipitated by CDF/LIF antiserum, and CDF/LIF antiserum partially blocked VIP induction in explants. CDF/LIF mRNA was increased in dissociated cell cultures, in ganglion explants andin vivoafter axotomy. Our results suggest that CDF/LIF released from ganglionic nonneuronal cells plays an important role in regulating VIP after axotomy. 1994 John Wiley & Sons, Inc.
Neurotrophic agents prevent motoneuron death following sciatic nerve section in the neonatal mouse
Authors: Li Linxi , Openheim Ronald W. , Lei Ming , Houenou Lucien J. 
Published: January 2005

AbstractWe have examined the ability of different neurotrophic and growth factors to prevent axotomy‐induced motoneuron cell death in the developing mouse spinal cord. After postnatal unilateral section of the mouse sciatic nerve, most motoneuron (MN) loss occurs in the lateral motor column of the fourth lumbar segment (L4). Significant axotomy‐induced cell death occurred after surgery performed on or before postnatal day (PN) 5. In contrast, no significant cell loss was found when axotomy was performed after PN10. Axotomy on PN2 or PN5 resulted in a 44% loss of L4 motoneurons by 7 days, and a 66% loss of motoneurons by 10 days postsurgery. Implantation of gelfoam presoaked in various neurotrophic factors at the lesion site rescued axotomized motoneurons. Nerve growth factor (NGF), nedurotrophin‐4/5 (NT‐4/5) and ciliary neurotrophic factor (CNTF) rescued 20%–30% of motoneurons, whereas brain‐derived neurotrophic factor (BDNF), neurotrophin‐3 (NT‐3), and insulin‐like growth factor 1 (IGF‐1) rescued virtually all motoneurons from axotomy‐induced death. By contrast, platelet‐derived growth factor (PDGF)‐AA, PDGF‐AB, basic fibroblast growth factor (bFGF), and interleukin (IL‐6) were ineffective on motoneuron survival following axotomy. NGF, BDNF, NT‐3, IGF‐1, and CNTF also prevented axotomy‐induced atrophy of surviving motoneurons. These data show that mouse lumbar motoneurons continue to be vulnerable to axotomy up to about 1 week after birth and that a number of trophic agents, including the neurotrophins, CNTF, and IGF‐1, can prevent the death of these neurons following axotomy. Our studies confirm and extend previous reports on the time course of axotomy‐induced mouse motoneuron death and the survival promoting effects of neurotrophic factors. 1994 John Wiley & Sons, Inc.
Motoneurons deprived of trophic support in vitro require new gene expression to undergo programmed cell death
Authors: Milligan C. E. , Oppenheim R. W. , Schwartz L. M. 
Published: January 2005

AbstractDuring normal development, large numbers of neurons die by programmed cell death. This phenomena has been extensively studied in the lateral motor column of chick embryos, where approximately 50% of the motoneurons that are initially produced, subsequently die due in part to competition for a limited supply of target‐derived trophic support. Inhibitors of RNA and protein synthesis block this cell loss in vivo, indicating a requirement for new gene expression (Oppenheim et al., 1990). Prior to their commitment to death, motoneurons can be isolated as a relatively pure population from chick spinal cord for in vitro study. Cells plated with muscle extract, a potent source of target‐derived trophic support, survive, and have large, phase‐bright cell bodies and extensive neurite outgrowth. In contrast, motoneurons cultured in the absence of muscle extract die within 48 h. This death can be blocked by the RNA synthesis inhibitor actinomycin D, at the time when the cells become committed to die, suggesting that new gene expression is required for cell death. DNA fragmentation and nuclear condensation indicate that some of these cells die by apoptosis. Therefore, it appears that many aspects of motoneuron development observed in vivo can be reconstituted in vitro. These cultures can be used as a model system for studying neuronal death and may contribute to an understanding of the molecular mechanisms that mediate programmed cell death during neuronal development. 1994 John Wiley & Sons, Inc.
Specific pathway selection by the early projections of individual peripheral sensory neurons in the embryonic medicinal leech
Authors: Jellies John , Johansen Kristen , Johansen Jørgen 
Published: January 2005

AbstractIn leech, the central annulus of each midbody segment possesses seven pairs of sensilla, which are mixed clusters of primary peripheral sensory neurons that extend their axons into the CNS where they segregate into distinct fascicles. Pathway selection by individual afferent growth cones of sensillar neurons was examined by double labeling using intracellular dye‐filling with anitobody labeling in early Hirudo medicinalis embryos. The monoclonal antibody Lan3–2 was used because sensillar neuronal tracts are specifically labeled by this antibody. Examining 68 individually filled neurons we found that sensillar neuron growth cones bifurcate within the CNS, that they project long filopodia capable to sampling the local environment, and that all of them appeared to choose a single particular CNS fascicle without apparent retraction or realignment of growth cones. Furthermore, each side of the bifurcating afferent growth cones always chose the same fascicle, implying a specific choice of a distinct labeled pathway. By dye‐filling individual central neurons (P‐cells), we show that there are centrally projecting axons present at the time sensillar afferents enter the ganglionic primordia and select a particular fascicle, and we confirm that at least the dorsal peripheral nerve is likely to be pioneered by central neurons, not by the peripheral afferent. In the sensillum studied here, we sound examples of sensory neurons extending axons into one of all the avilable fascicles. Thus, an individual embryonic sensillum possesses a heterogeneous population of afferents with respect to the central fascicle chosen. This is consistent with the idea that segregation into distinct axon fascicles may be based upon functional differences between individual afferent neurons. Our findings argue strongly in favor of specific pathway selection by afferents in this system and are consistent with previous suggestions that there exists a hierarchy of cues, including surface glycoconjugates that mediate navigation of the sensillar growth cones and the fasciculation of their axons. 1994 John Wiley & Sons, Inc.
Maturation of neurites in mixed cultures of spinal cord neurons and muscle cells from Xenopus laevis embryos followed with antibodies to neurofilament proteins
Authors: Lin Weichun , Szaro Ben G. 
Published: January 2005

AbstractDissociated cell cultures of Xeopus laevis embryonic spinal cord have proved useful for studying the differentiation of neuronal ionic channel and membrane properties and for examining the dynamics of microtubules in developing neurons. To examine their usefulness for studying neurofilaments in developing neurites, we prepared similar cultures from stage 22 embryos. Between 3 and 55 h after plating, these cultures were fixed and immunostained with antibodies directed against various epitopes of neurofilament proteins from X. Laevis. These antibodies were specific for nonphosphorylated epitopes of the two low molecular weight Xenopus neurofilament proteins (Xenopus NF‐L and the Xenopus neuronal intermediate filament protein, XNIF), both phosphorylated and nonphosphorylated epitopes of the Xenopus middle molecular weight neurofilament protein (NF‐M), and a nonphosphorylated epitope of the Xenopus high molecular weight neurofilament protein (NF‐H). The emergence of these neurofilament proteins in culture was compared to the time course previously reported for them in Xenopus spinal cord neurons in situ. To facilitate the comparison of times in culture to developmental stages, the age of cultured neurons was converted to an equivalent Nieuwkoop and Faber normal stage using data presented here on the effect of changing temperature on developmental rates of X. laevis. With the exception of the nonphosphorylated epitope of NF‐H, which is indicative of the most mature axons found in situ. the emergence of the other neurofilament protein antibody epitopes closely paralleled that previously reported for these antibodies in situ. Thus, with respect to XNIF, NF‐M, and NF‐L, the neurities of cultured neurons were typical of young embryonic Xenopus laevis spinal cord axons. This system should prove useful for studying both the function of these neurofilament proteins during the early stages of axonal development and the dynamics of their transport. 1994 John Wiley & Sons, Inc.
Influence of factors released from sciatic nerve on adult dorsal root ganglion neurons
Authors: Dobretsov Maxim , Dobretsov Anna , Kuffler Damien P. 
Published: January 2005

AbstractPrevious experiments have shown that medium conditioned (CM) by denervated peripheral nerve contains a process outgrowth promoting factor (s) for cultured adult frog dorsal root ganglion (DRG) neurons. The present experiments further characterize the influences of these factors on DRG neurons. The growth factors increases average process length by threefold, restricts the number of processes extended from four to two while simultaneously altering the morphology of those processes. Neurons with preexisting processes respond to the factors by significantly increasing the length of 35% of these processes. Only the newly elongated portions of preexisting processes have morphology typical of factor‐induced processes, while the previously extended portions retain their original morphology. The number of processes of these neurons remains unchanged. Although composed of two population according to size, neurons in both populations are similarly influenced, suggesting that the factors influence neurons of all sensory modalities. To look at other possible influences of the nerve‐released factors, a novel simple culture system has been developed in which concentration gradients of these factors can be established and maintained. The front of the outgrowth‐promoting influence in these cultures could be followed over time (up to 9 days) as it affected the process length and morphology of neurons at increasing distances (up to 8 mm) from the source of the factors. The trophic factors may play important roles during regeneration in vivo by influencing the cytoskeletal organization in the cell body and growth cones to bring about a stabilization and consolidation of growth cone membrane of only a limited number of processes resulting in increasing the rate of process elongation. The factors may also serve to direct process outgrowth, which can be examined using the new culture system. 1994 John Wiley & Sons, Inc.
The p75 neurotrophin receptor
Authors: Chao Moses V. 
Published: January 2005

AbstractThe low‐affinity p75 molecule and trk tyrosine kinases serve as receptors for target‐derived neurotrophins. While the mechanism by which receptor tyrosine kinases impart intracellular signaling has become well understood, the precise roles of the p75 receptor are not fully defined. The p75 neurotrophin receptor belongs to a family of transmembrane molecules which also serve as receptors for the tumor necrosis factor family of cytokines. Each receptor shares a common extracellular structure highlighted by conserved cysteine‐rich repeats. Because NGF, BDNF, NT‐3, and NT‐4/5 bind to p75 with similar affinity, p75 may either act as a common subunit in a neurotrophin receptor complex with trk family members, or act by independent mechanisms to mediate biological actions of each neurotrophin. 1994 John Wiley & Sons, Inc.
Expression of trk and neurotrophin mRNA in dorsal root and sympathetic ganglia of the quail during development
Authors: Zhang Damin , Yao Lihua , Bernd Paulette 
Published: January 2005

AbstractThe nerve growth factor (NGF) family of neurotrophins exerts effects by binding to products of the trk family of proto‐oncogenes. We examined the expression of both trk and neurotrophin mRNA during the entire range of development of quail dorsal root ganglia (DRG) and sympathetic ganglia (SG) using in situ hybridization and reverse transcriptase‐polymerase chain reaction (RT‐PCR). TrkC mRNA was present in neurons or their precursors from the time of formation of DRG (stage 18, embryonic day 2.5 [E2.5]) and throughout development. The number of labeled cells changes, however, from a majority to a minority at later developmental stages. Expression of trkA mRNA was not detected in DRG until stage 30 (E6) by in situ hybridization, although results with RT‐PCR were positive at stage 23 (E3.5). Labeling was always detected on majority of neurons or their precursors. SG exhibited low level of trkC mRNA during the later stages of development, whereas trdA mRNA was present from stage 34 onward in most neurons. We have also shown that NGF, neurotrophin‐3 (NT‐3), and brain‐derived neurotrophic factor (BDNF) mRNA were present at all stages examined (stages 23 through 45 for DRG, stages 35–36 and 45 for SG). In DRG, NGF mRNA expression was limited to support cells, whereas NT‐3 and BDNF mRNA were detected in both neurons and support cells. These results suggest that neurotrophins could serve a local function in developing ganglia, which can be correlated with the presence of their respective receptors. 1994 John Wiley & Sons, Inc.
Birth times of neurons in labellar taste sensilla of the blowfly Phormia regina
Authors: Pollack Gerald S. , Lakes‐Harlan Reinhard 
Published: January 2005

AbstractWe studied the birth times of neurons of labellar taste sensilla in blowflies using incorporation of the thymidine analogue 5‐bromodeoxyuridine (BrdU) as an indicator of birth time. We found that one of the two main sensillum types, the taste papillae, arise according to a clear spatial gradient of birth times, whereas the other sensillum type, taste hairs, arise without any apparent spatial ordering. Within each sensillum type, there was a strong tendency for either all or none of the neurons to have incorporated BrdU. Among those rare sensilla in which only some of the neurons incorporated BrdU, there were clear patterns of the distribution of labeled and unlabeled neurons per sensillum. These results suggest that subsets of the neurons of a sensillum are siblings, and thus argue against the possibility that the several neurons of a sensillum arise from a single stem cell precursor through repeated asymmetrical divisions. © 1995 John Wiley & Sons, Inc.
Ethanol influences on the chick embryo spinal cord motor system: Analyses of motoneuron cell death, motility, and target trophic factor activity and in vitro analyses of neurotoxicity and trophic factor neuroprotection
Authors: Heaton Marieta B. , Bradley Douglas M. 
Published: January 2005

AbstractA series of in vivo and in vitro experiments were conducted to determine the influence of prenatally administered ethanol on several aspects of the developing chick embryo spinal cord motor system. Specifically, we examined: (1) the effect of chronic ethanol administration during the natural cell death period on spinal cord motoneuron numbers; (2) the influence of ethanol on ongoing embryonic motility; (3) the effect of ethanol exposure on neurotrophic activity in motoneuron target tissue (limbbud); and (4) the responsiveness of cultured spinal cord neurons to ethanol, and the potential of target‐derived neurotrophic factors to ameliorate ethanol neurotoxicity. These studies revealed the following: Chronic prenatal ethanol exposure reduces the number of motoneurons present in the lateral motor column after the cell death period [embryonic day 12 (E12)]. Ethanol tends to inhibit embryonic motility, particularly during the later stages viewed (E9‐E11). Chronic ethanol exposure reduces the neurotrophic activity contained in target muscle tissue. Such diminished support could contribute to the observed motoneuron loss. Direct exposure of spinal cord neurons to ethanol decreases neuronal survival and process outgrowth in a dose‐dependent manner, but the addition of target muscle extract to ethanol‐containing cultures can ameliorate this ethanol neurotoxicity. These studies demonstrate ethanol toxicity in a population not previously viewed in this regard and suggest a mechanism that may be related to this cell loss (i.e., decreased neurotrophic support). © 1995 John Wiley & Sons, Inc.
Telencephalic and diencephalic origin of radial glial processes in the developing preoptic area/anterior hypothalamus
Authors: Tobet Stuart A. , Paredes Raul G. , Chickering Troy W. , Baum Michael J. 
Published: January 2005

AbstractNeuronal birth‐dating sudies using [3H]thymidine have indicated that neurons in the preoptic area/anterior hypothalamus (POA/AH) are derived primarily from progenitors in proliferative zones surrounding the third ventricle. Radial glial processes are potential guides for neuronal migration, and their presence and orientation during development may provide further information about the origin of cells in the POA/AH. In addition to determining the orientation of radial glial fibers, we examined the relationship of neurons with identified birth dates to radial glial processes in the developing POA/AH of ferrets. Neuronal birth dates were determined by injecting ferret fetuses with bromodeoxyuridine (BrdU) at several different gestational ages; brains were taken from ferret kits at subsequent prenatal ages. Sections were processed for immunocytochemistry to reveal vimentin or glial fibrillary acidic protein in radial glia, or BrdU‐labeled cell nuclei. Numerous radial glial processes extended from the lateral ventricles through ventral portions of the septal region to the pial surface of the POA/AH. These fibers both encapsulated and coursed ventrally through and around the anterior commissure of ferret, rat, and mouse fetuses. These ventrally directed fibers were less evident at older ages. In double‐labeled sections from ferrets, BrdU‐labeled cells in the dorsal POA/AH were often aligned in the same dorsal‐ventral orientation as adjacent radial glial fibers. We suggest that a subset of neurons, originating in telencephalic proliferative zones, migrates ventrally along radial glial guides into the dorsal POA/AH. © 1995 John Wiley & Sons, Inc.