bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectrum of in vitro differentiation of quail trunk neural crest cells isolated by cell sorting using the HNK‐1 antibody and analysis of the adrenergic development of HNK‐1+ sorted subpopulations
Authors: Maxwell Gerald D. , Forbes M. Elizabeth 
Published: January 2005

AbstractPrevious work has demonstrated that catecholamine‐containing cells differentiate preferentially from populations of quail trunk neural crest cells isolated by cell sorting using the HNK‐1 antibody (Maxwell, Forbes, and Christie, 1988). In the present work, we examine several additional features of the differentiation of these sorted cell populations. As one part of this study, the development of subpopulations of the HNK‐1+‐sorted neural crest cells has been investigated. Twice as many catecholamine‐positive and total cells developed from the brightest third of the HNK‐1+ cells compared to the remaining HNK‐1+ cells, but the proportion of catecholamine‐containing cells was similar in both populations. When either of these HNK‐1+ subpopulations were grown together with HNK‐1− cells, no reduction in the number of adrenergic cells was observed. These results indicate that subpopulations of HNK‐1+ cells are qualitatively similar and that their adrenergic development is not affected by HNK‐1− cells. In the second part of this study, we investigate the specificity of differentiation of HNK‐1+‐ and HNK‐1−‐sorted cells by examining several additional phenotypic markers of development. We found that tyrosine hydroxylase and somatostatin immunoreactive cells developed from the HNK‐1+‐sorted population, while few, if any, cells bearing these phenotypic markers appeared in the HNK‐1−‐sorted population. In marked contrast, substantial numbers of cells immunoreactive for A2B5, E/C8, and NF‐160 differentiated from both the HNK‐1+‐ and the HNK‐1−‐sorted cell populations. The A2B5, E/C8, and NF‐160 immunoreactive cells exhibited a variety of morphologies ranging from nonneuronal to neuronal in both sorted populations. Taken together, these results indicate that the presence of the HNK‐1 antigen(s) on the trunk neural crest cell surface at 2 days in vitro is rather tightly correlated with the differentiation of adrenergic and some peptidergic cells, but much less so with other classes of neural cells including A2B5, E/C8, and NF‐160 immunoreactive cells. Thus, these findings support the view that cell surface differences are correlated with and may contribute to the generation of the phenotypic diversity of neural crest cell derivatives.
A specific 70K protein found in epileptic rat cortex: Induction of bursting activity and negative resistance by its intracellular application in Euhadra neurons
Authors: Onozuka Minoru , Imai Shizuko , Furuichi Hiroyasu , Ozono Satoru 
Published: January 2005

AbstractThe effect of 70‐kD protein (P70, a specific protein found in cobalt‐induced epileptogenic focus of rat cerebral cortex) on membrane properties was examined in identified neurons of the snail, Euhadra peliomphala, using the pressure injection method combined with the voltage‐clamp technique. In neurons that normally exhibited spontaneous regular firing, intracellular injection of P70 elicited bursting activity and a negative slope resistance (NSR) region in their current‐voltage (I‐V) curve in a manner corresponding to the duration of its injection. These responses were suppressed by prior injection of an antibody to P70 into the neurons, and were markedly inhibited by a reduction of extracellular Na+ ions and the anticonvulsant agent phenytoin, but not by Co2+‐substituted Ca2+‐free saline. In addition, intracellularly applied P70 potentiated both bursting activity and the NSR induced by a Na channel activator, veratridine. However, prior application of a saturating dose of this activator occluded the effect of P70. These results suggest that P70 elicits a Na+‐dependent negative resistance, which may contribute to the generation of bursting activity.
Characterization and spatial distribution of the ELAV protein during Drosophila melanogaster development
Authors: Robinow Steven , White Kalpana 
Published: January 2005

AbstractThe embryonic lethal abnormal visual system (elav) gene of Drosophila melanogaster is required for the development and maintenance of the nervous system. Transcripts from this locus are distributed ubiquitously throughout the nervous system at all developmental stages. A product of this gene, the ELAV protein, has homology to known RNA binding proteins. The localization of the ELAV protein was studied in all developmental stages using antibodies that were generated against a hybrid protein made in Escherichia coli. In general, these data are consistent with previous results and demonstrate that (1) the ELAV protein is detected in the developing embryonic nervous system at a time coincident with the birth of the first neurons, (2) the ELAV protein is first detected in the majority of neurons of the central and peripheral nervous systems of embryos, larvae, pupae, and adults, (3) the ELAV protein appears to be localized to the nucleus, and (4) the ELAV protein is not detected in neuroblasts or identifiable glia. These data also provide new information concerning elav expression and show that (1) ELAV is not expressed in the ganglion mother cells (GMCs), (2) while the ELAV protein is localized to the nucleus, it is not uniformly distributed throughout this structure, and (3) other Drosophila species do express an ELAV‐like antigen. We propose that the elav gene provides a neuronal‐housekeeping function that is required for the successful posttranscriptional processing of transcripts from a set of genes the function of which is required for proper neuronal development and maintenance.
Expression of a novel nuclear protein is correlated with neuronal differentiation in vivo
Authors: Paden Charles M. , Cranston Harwood , Hapner Sharon J. 
Published: January 2005

AbstractWe report the production of a monoclonal antibody (MAb 526) that recognizes a novel, developmentally regulated nuclear protein expressed in neurons throughout the rat nervous system. Analysis of whole brain and cell nuclear extracts by SDS‐PAGE and immunoblotting determined that MAb 526 recognizes a single nuclear protein (np) of apparent molecular weight 42 kD, designated np526, as well as a slightly larger (ca. 44 kD) cytoplasmic protein. Light microscopic immunocytochemistry showed np526 to be present in neurons of all types throughout the central and peripheral nervous systems. Nuclei of both fibrous and protoplasmic astrocytes were also immunoreactive, but oligodendrocyte nuclei were negative. Positive, but highly variable immunocytochemical staining of nonneural cell nuclei in a variety of other tissues was also observed. Electron microscopic (EM) immunocytochemistry using pre‐embedding peroxidase methods revealed that np526 is associated with euchromatin or with the edges of condensed chromatin bundles in neurons, indicating that it is likely to be a chromosomal protein. Most interestingly, the expression of np526 was found to be developmentally regulated in brain. Immunocytochemical analysis of the developing cerebral cortex from embryonic day (E) 16 to postnatal day (P) 4 and cerebellum from P4 to P18 revealed that np526 first appears in central neurons following the cessation of mitosis and that the intensity of nuclear staining increases during subsequent neuronal maturation. To our knowledge, np526 is the first presumptive chromosomal protein whose expression has been precisely correlated with the early postmitotic differentiation of mammalian neurons.
Cholinergic differentiation in neurogenic basal forebrain cultures
Authors: Martinic Marjana , Lambert Mary P. , Hua Sherwin , Klein William L. 
Published: January 2005

AbstractTo study early events in the central nervous system (CNS) cholinergic development, cells from rat basal fore brain tissue were placed in culture at an age when neurogenesis in vivo is still active [embryonic day (E) 15]. The rapid mortality of these cells in defined medium, with 50% mortality after 5–10 h, was blocked completely by soluble proteins from the olfactory bulb (a basal forebrain target), extending earlier observations (Lambert, Megerian, Garden, and Klein, 1988). Treated cultures were capable of incorporating thymidine into DNA, and most cells incorporating 3H‐thymidine (>90%) also stained positive for neurofilament, confirming neuronal proliferation in the supplemented cultures. A small percentage of 3H‐thymidine labelled cells were glial fibrillary acidic protein (GFAP) positive, but growth factors that support astroglial proliferation [epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and insulin‐like growth factor (IGF‐1)] were not sufficient for neuronal support. After 5 culture days with supplemented medium, almost 50% of the cells showed choline acetyltransferase (ChAT) immunofluorescence. The cholinergic neurons typically formed clusters separate from noncholinergic cells. These mature cultures did not develop if young cultures were treated with aphidicolin to block DNA synthesis. The data show that cultures of very young rat basal forebrain cells can be neurogenic, giving rise to abundant cholinergic neurons, and that early cell proliferation is essential for long‐term culture survival.
Structure‐activity relationship of the neurotransmitter alpha‐bag cell peptide on Aplysia LUQ neurons: Implications regarding its inactivation in the extracellular space
Authors: Owens David F. , Menon Jaishri G. , Rothman Barry S. 
Published: January 2005

AbstractAlpha‐bag cell peptide [α‐BCP (Ala‐Pro‐Arg‐Leu‐Arg‐Phe‐Tyr‐Ser‐Leu)] is a neurotransmitter that mediates bag cell‐induced inhibition of left‐upper‐quadrant (LUQ) neurons L2, L3, L4, and L6 in the abdominal ganglion of Aplysia. Our recent biochemical studies have shown that α‐BCP[1–9] is cleaved into α‐BCP[1–2], [3–9], [1–5], [6–9], and [7–9] by a combination of three distinct peptidase activities located within the extracellular spaces of the CNS: A diaminopeptidase‐IV (DAP‐IV)‐like enzyme cleaves α‐BCP[1–9] at the 2–3 peptide bond; a neutral metalloendopeptidase (NEP)‐like enzyme cleaves either α‐BCP[1–9] or α‐BCP[3–9] at the 5–6 bond; an aminopeptidase M‐II (APM‐II)‐like enzyme cleaves α‐BCP[6–9] at the 6–7 bond, but cleaves neither α‐BCP[1–9], nor the other ganglionic peptidase products. To further understand the manner in which α‐BCP is inactivated after release, that is loses its electro‐physiological activity, we studied its structure‐activity relationship by recording intracellularly from LUQ neurons in isolated abdominal ganglia that were arterially perfused with peptides dissolved in artificial sea water. The effects of α‐BCP[1–9] and 15 of its fragments ([1–8], [1–7], [1–6], [1–5], [2–9], [3–9], [3–8], [6–9], [7–9], [8–9], [6–7], [6–8], [1–2], Phe, Tyr) indicated that the sequence Phe6‐Tyr7 was both necessary and sufficient to produce LUQ inhibitory activity. The combined results of our electrophysiological and biochemical studies strongly suggest that α‐BCP[1–9] is inactivated by the serial actions of the NEP‐like and APM‐II‐like peptidases; that is, the NEP‐like enzyme yields an electro‐physiologically active product, α‐BCP[6–9], that is cleaved by the APM‐II‐like enzyme to yield inactive α‐BCP[7–9]. Furthermore, because α‐BCP[6–9] is more active than α‐BCP[1–9], cleavage by the NEP‐like enzyme potentiates α‐BCP's activity. © 1992 John Wiley & Sons, Inc.
The development of ipsilateral retinal projections into the tectum in the cichlid fish Haplochromis burtoni: A dil study in fixed tissue
Authors: Fritzsch Bernd , Wilm Claudia 
Published: January 2005

AbstractThe normal development of the retinal projection was studied in a bony fish with Dil. Between 5.5 and 10 days postfertilization the contralateral retinal projection grows from the rostral pole of the tectum across its center. A maximum of 15 retinal fibers reaches the ipsilateral tectum. In 33‐day‐old juvenile animals, less than 15 ipsilateral fibers terminate in the entire tectum. Ipsilaterally projecting ganglion cells (maximal number = 20 cells) are scattered throughout the entire retina, and the location of ganglion cells in the retina and axonal terminations in the tectum display a large interindividual variability. This suggests that the small adult contingent of ipsilateral fibers in this bony fish develops without an initial exuberant ipsilateral retinal projection that is later pruned back. © 1992 John Wiley & Sons, Inc.
Hormone accumulation in song regions of the canary brain
Authors: Brenowitz Eliot A. , Arnold Arthur P. 
Published: January 2005

Abstract[3H]Testosterone (T) was injected into male and female canaries (Serinus canarius), a species in which females are able to sing but do so more rarely and more simply than males. Autoradiographic analysis revealed that males and females have equal proportions of cells labeled by T or its metabolites in four song control nuclei: the high vocal center (HVC), the lateral portion of the magnocellular nucleus of the anterior neostriatum (IMAN), the robust nucleus of the archistriatum (RA), and the hypoglossal motor nucleus (nXII). Labeled cells were also observed in both sexes in the medial portion of MAN, and in hypothalamic nuclei. In both sexes, labeled cells in HVC, IMAN, RA, and nXII were larger than unlabeled cells. There were no sex differences in the size of either labeled or unlabeled cells in these song nuclei. The density of labeled cells per unit volume of tissue did not differ between the sexes in any song nucleus analyzed. However, because males have larger HVC and RA than females, males have a greater total number of hormone‐sensitive cells in these regions than do females. Comparison of these results with measures of hormone accumulation in zebra finches and tropical duetting wrens suggests that the complexity of song that a bird can produce is correlated with the total number of hormone‐sensitive cells in song nuclei. © 1992 John Wiley & Sons, Inc.
Olfactory physiology in the Drosophila antenna and maxillary palp: acj6 Distinguishes two classes of odorant pathways
Authors: Ayer Richard K. , Carlson John 
Published: January 2005

AbstractThis article provides characterization of the electrical response to odorants in the Drosophila antenna and provides physiological evidence that a second organ, the maxillary palp, also has olfactory function in Drosophila. The acj6 mutation, previously isolated by virtue of defective olfactory behavior, affects olfactory physiology in the maxillary palp as well as in the antenna. Interestingly, abnormal chemosensory jump 6 (acj6) reduces response in the maxillary palp to all odorants tested except benzaldehyde (odor of almond), as if response to benzaldehyde is mediated through a different type of odorant pathway from the other odorants. In other experiments, different parts of the antenna are shown to differ with respect to odorant sensitivity. Evidence is also provided that antennal response to odorants varies with age, and that odorants differ in their age dependence. © 1992 John Wiley & Sons, Inc.
Behavior of fish retinal growth cones encountering chick caudal tectal membranes: A time‐lapse study on growthcone collapse
Authors: Bastmeyer Martin , Stuermer Claudia A. O. 
Published: January 2005

AbstractIn a cross species in vitro assay, growth cones from fish temporal retina elongating on laminin lanes were observed with time‐lapse videomicroscopy as they encountered lanes and territories that carried membrane fragments from the chick caudal tectum. Caudal tectal membranes of adult fish and embryonic chick are known to possess a repellent guiding component for temporal retinal axons. The caudal membranes of chick exert a particularly strong influence on fish temporal axons. Contacts with chick caudal membranes by just a few filopodia and parts of the lamellipodia evoked a turning response away from the membrane lane of the entire growth cone. Contacts by filo‐ and lamellipodia over the entire circumference of the growth cone, however, caused invariably growth cone collapse and retraction. During growth cone turning and collapse and retraction, filopodia remained in contact with the tectal membrane fragments, suggesting strong membrane–filopodia adhesion simultaneous to growth cone repulsion by the repellent guiding component. © 1993 John Wiley & Sons, Inc.
Restriction of neurogenic ability during neural crest cell differentiation
Authors: Vogel Kristine S. , Marusich Michael F. , Weston James A. 
Published: January 2005

AbstractMultipotent neural crest cells undergo developmental restrictions during embryogenesis and eventually give rise to the neurons and glia of the peripheral nervous system, melanocytes, and pheochromocytes. To understand how neuronal potential is restricted to a subpopulation of crest‐derived cells, we have utilized sensitive markers of early neuronal differentiation to assess neurogenesis in crest‐derived cell populations subjected to defined experimental conditions in vitro and in vivo. We describe environmental conditions that either (a) result in the irreversible loss of neurogenic potential over a characteristic time course or (b) maintain neurogenic potential among neural crest cells. © 1993 John Wiley & Sons, Inc.
Octopamine effects mimick state‐dependent changes in a proprioceptive feedback system
Authors: Büschges Ansgar , Kittmann Rolf , Ramirez Jan‐Marino 
Published: January 2005

AbstractThe modulatory actions of the biogenic amine octopamine on the femur tibia (FT) control loop in the stick insect Carausius morosus were examined. The response properties of the FT control loop were determined under open loop conditions. Mechanical stimulation of the femoral chordotonal organ (fCO) was the input and tibial movement and motoneuronal activity were measured as the output of the system. Following octopamine injection into the hemolymph of intact, inactive animals, two consecutive phases occurred at the behavioral level. Octopamine caused initially an activation of the animal. During this first phase (3.5–12 min duration) the response properties of the FT control loop were similar to those found in animals that were activated by tactile stimuli under normal conditions. Afterward, animals became inactive. During this second phase (15–20 min duration), the gain of the control loop was zero and no resistance reflex in the FT joint was generated in response to fCO stimulation. However, active movements of the tibia could still be elicited. As we could show in restrained animals, where dl‐octopamine was applied topically onto the undesheated mesothoracic ganglion, the complete suppression of the resistance reflex on the motoneuronal level was dose dependent starting at concentrations of 5 ± 10−3 M octopamine. We could show that octopamine specifically suppressed the pathways involved in the resistance reflex, while feedback loop responses to fCO stimuli typical for active animals could still be elicited. Our results indicate that an increase in the octopamine concentration mimicks activation of the animal: Properties being characteristic for the control of the FT joint in the inactive animal are inhibited by octopamine, while properties of the FT control loop typical for the active animal appear to be facilitated following octopamine injection. The results clearly demonstrate that different pathways in the neuronal network underlying the FT control loop are involved in the responses of the control loop to fCO stimuli in the inactive and active behavioral states of the stick insect. © 1993 John Wiley & Sons, Inc.
Testosterone‐induced changes in adult canary brain are reversible
Authors: Brown Susan D. , Bottjer Sarah W. 
Published: January 2005

AbstractBrain nuclei that control song are larger in male canaries, which sing, than in females, which sing rarely or not at all. Treatment of adult female canaries with testosterone (T) induces song production and causes song‐control nuclei to grow, approaching the volumes observed in males. For example, the higher vocal center (HVC) of adult females approximately doubles in size by 1 month following the onset of T treatment. Male HVC projects to a second telencephalic nucleus, RA (the robust nucleus of the archistriatum), which projects in turn to the vocal motor neurons. Whether HVC makes a similar connection in female canaries is not known, although HVC and RA are not functionally connected in female zebra finches, a species in which testosterone does not induce neural or behavioral changes in the adult song system. This experiment investigated whether HVC makes an efferent projection to RA in normal adult female canaries, or if T is necessary to induce the growth of this connection. In addition, we examined whether T‐induced changes in adult female canary brain are reversible. Adult female canaries received systemic T implants that were removed after 4 weeks; these birds were killed 4 weeks after T removal (Testosterone‐Removal, T‐R). Separate groups of control birds received either (a) T implants for 4 weeks which were not removed (Testosterone‐Control, T‐C) or (b) empty implants (Untreated Control, øO‐C). Crystals of the fluorescent tracer DiI were placed in the song‐control nucleus HVC in order to anterogradely label both efferent targets of HVC, RA and Area X. Projections from HVC to RA and Area X were present in all treatment groups including untreated controls, and did not appear to differ either qualitatively or quantitatively. Thus, formation of efferent connections from HVC may be prerequisite to hormone‐induced expression of song behavior in adult songbirds. The volumes of RA and Area X were measured using the distribution of anterograde label as well as their appearance in Nissl‐stained tissue. RA was larger in T‐treated control birds than in untreated controls. Experimental birds in which T was given and then removed (T‐R) had RA volumes closer in size to untreated controls (ø‐C). Because the volume of RA in T‐treated controls (T‐C) was larger than that of birds that did not receive T (ø‐C), we conclude that the volume of RA increased in both T‐C and T‐R birds but regressed upon removal of T in T‐R birds. Surprisingly, the volume of Area X did not increase in T‐treated birds. Birds in this study were maintained on short days, suggesting that T‐induced growth of Area X reported previously may have resulted from an interaction between T and another seasonal or photoperiodic factor induced by exposure to long daylengths. © 1993 John Wiley & Sons, Inc.
Synaptic loss following removal of serotoninergic fibers in newly hatched and adult chickens
Authors: Okado Nobuo , Cheng Ling , Tanatsugu Yasuyuki , Hamada Shun , Hamaguchi Kayoko 
Published: January 2005

AbstractNeurotransmitters such as serotonin (5HT) may have nontransmitter, trophic‐like functions in the developing and adult nervous system. In order to examine this possibility in the avian spinal cord, we have quantified synapse numbers on spinal neurons following treatment with drugs that result in the destruction of 5HT positive axons. Either p‐chlorophenylalanine or reserpine was injected into newly hatched or adult chickens. Following treatment for 7 days the density of nonserotoninergic synapses was considerably decreased in the targets of 5HT fibers. By contrast, neither change was observed in the dendritic structures of spinal motoneurons or in the distribution of substance P and enkephalin positive fibers. These data suggest that 5HT may play an important role in the normal increase and maintenance of synapses in developing and adult animals. A lesion of 5HT neurons may not only alter neurochemistry but also alter the general synaptic structures of the brain. While 5HT containing fibers were depleted in a dose‐dependent fashion we cannot rule out the possibility that other neurotransmitter systems were depleted at higher dose of PCPA and reserpine. © 1993 John Wiley & Sons, Inc.