bluuebunny/crossref_metadata_2025_split huggingface dataset:
Right‐side dominance for song control in the zebra finch
Authors: Williams Heather , Crane Linda A. , Hale Timothy K. , Esposito Matthew A. , Nottebohm Fernando 
Published: January 2005

AbstractAdult male zebra finches underwent unilateral denervation of the syrinx or unilateral lesion of the forebrain nucleus HVC known to be important for song control. Disruptive effects of song were greater after right‐side than after left‐side operations. After denervation of the right half of the syrinx, the fundamental frequencies of all syllables within a song converged on a value near 500 Hz, and nearly all syllables were altered in type. In contrast, the syllables produced after denervation of the left side of the syrinx largely maintained their preoperative frequencies, and fewer syllables changed in type. Unlike nerve sections, HVC lesions did not result in strikingly lateralized effects on syllable phonology; however, HVC lesions did affect the temporal patterning of a bird's song, whereas nerve sections did not, and changes in temporal patterning were more marked after right than after left HVC lesions. Right‐side dominance for zebra finch song control is the reverse of that described in other songbird species with lateral asymmetry for vocal communication. We suggest that the need for a dominant side is more important than the side of dominance. © 1992 John Wiley & Sons, Inc.
Cellular interactions determine neuronal phenotypes in rodent retinal cultures
Authors: Reh Thomas A. 
Published: January 2005

AbstractProgenitor cells isolated from early rat embryo retinas differentiate into phenotypes normally generated early in retinal development (e.g., ganglion cells), whereas progenitors isolated from postnatal retinas differentiate into later‐generated retinal cell types (e.g., rod photoreceptors; Reh and Kljavin, J. Neurosci. 9:4179–4189; 1989; Adler and Hatlee, 1989; Science 243:391–393; Sparrow, Hicks, and Barnstable, 1990, Dev. Brain Res. 51:69–84). To determine whether this change in committment is intrinsic to the progenitor cells, or alternatively can be modified by interactions with their developing environment, I co‐cultured mouse and rat retinal cells, from different developmental stages, and identified the resulting phenotypes with species‐specific and cell class‐specific antibodies. I found that the phenotypes into which mouse neuroepithelial cells differentiate depends on the phenotypes of the rat cells that surround them. Retinal precursor cells from embryonic day (E) 10–12 will adopt the rod photoreceptor phenotype only when close to cells expressing this phenotype. By contrast, when the E10–12 retinal progenitor cells are cultured with cells from the cerebral cortex, they differentiate primarily into large multipolar neurons, similar in their morphology and antigen expression to retinal ganglion cells. These results indicate that interactions among the cells of the developing retina are important in the determination of cell fate. © 1992 John Wiley & Sons, Inc.
Influence of spinal cord transection on the presence and axonal transport of CGRP‐, chromogranin A‐, VIP‐, synapsin I‐, and synaptophysin‐like immunoreactivities in rat motor nerve
Authors: Li Jia‐Yi , Kling‐Petersen Anne , Dahlström Annica 
Published: January 2005

AbstractUsing immunofluorescence and cytofluorimetric scanning (CFS), we investigated the short‐term (1‐7 days) influence of lower thoracic spinal cord transection on lumbar motor neurons. The content of calcitonin gene‐related peptide‐ (CGRP) like immunoreactivity (LI), chromogranin A (Chr A) ‐LI, vasoactive intestinal polypeptide (VIP)‐LI, Syn I‐LI, and synaptophysin (p38)‐LI in motor perikarya, and the anterograde and retrograde axonal transport of these substances in the sciatic nerve, were studied in nerve crush (6 h) experiments. During the week after transection, CGRP‐LI in perikarya decreased, whereas Chr A‐LI increased. VIP‐LI, co‐localized with Chr A‐LI in motor perikarya, did not change after transection. The antero‐ and retrograde transport of CGRP‐LI in the sciatic nerve, occurring in both motor and sensory axons, appeared unchanged in cytofluorimetric scanning (CFS) graphs, but the microscopical picture clearly showed that large motor axons had a decreased content of CGRP‐LI at 3 and 7 days posttransection, whereas thinner axons were unchanged in fluorescence intensity. The anterograde transport of Chr A‐LI, present in both motor and postganglionic adrenergic axons, was decreased 1 and 3 days after lesion, but returned to control by day 7. There was a marked decrease in anterograde transport of VIP‐LI, present mainly in postganglionic sympathetic axons, at day 3, but at 7 days transport was normal. The amounts of transported p38, the synaptic vesicle marker, were in the normal range during the whole period. Syn I‐LI accumulation anterogradely was somewhat decreased at 3 and 7 days posttransection, and at 1 day the retrograde accumulation was significantly increased. The results suggest that removal of supraspinal input to intact lower motor neurons causes alterations in metabolism and axonal transport of organelle‐associated substances, partly probably related to the complex pattern of transmitter leakage from degenerating, descending nerve terminals. These alterations appear to take place also in postganglionic sympathetic neurons in the sciatic nerve, that originate in the lumbar sympathetic chain. © 1992 John Wiley & Sons, Inc.
Dendritic reorganization of an identified neuron during metamorphosis of the moth Manduca sexta: The influence of interactions with the periphery
Authors: Kent Karla S. , Levine Richard B. 
Published: January 2005

AbstractDuring metamorphosis of the moth, Manduca sexta, an identified leg motor neuron, the femoral extensor motor neuron (FeExt MN) undergoes dramatic reorganization. Larval dendrites occupy two distinct regions of neuropil, one in the lateral leg neuropil and a second in dorsomedial neuropil. Adult dendrites occupy a greater volume of lateral leg neuropil but do not extend to the dorsomedial region of the ganglion. The adult dendritic morphology is acquired by extreme dendritic regression followed by extensive dendritic growth. Towards the end of larval life, MN dendrites begin to regress, but the most dramatic loss of dendrites occurs in the 3 days following pupation, such that only a few sparse dendrites are retained in the lateral region of leg neuropil. Extensive dendritic growth occurs over the subsequent days such that the MN acquires an adult‐like morphology between 12 and 14 days after pupation. This basic process of dendritic remodeling is not dependent upon the presence of the adult leg, suggesting that neither contact with the new target muscle nor inputs from new leg sensory neurons are necessary for triggering dendritic changes. The final distribution of MN dendrites in the adult, however, is altered when the adult leg is absent, suggesting that cues from the adult leg are involved in directing or shaping the growth of MN dendrites to specific regions of neuropil. © 1993 John Wiley & Sons, Inc.
Testosterone propionate administration prevents the loss of neurons within the central part of the medial peroptic nucleus
Authors: Dodson Robin E. , Gorski Roger A. 
Published: January 2005

AbstractIn the rat, the central part of the medial preoptic nucleus (MPNc) of the male is larger in volume and has a greater number of neurons than that of the female. The nucleus of the female, however, can be “sex reversed” by exposing the rat to gonadal steroids perinatally. The purpose of the present study was to examine the development of the MPNc to determine when the sex difference first appears and whether this difference occurs due to the relative accumulation of neurons into the compact part of the MPNc of the male and sex‐reversed female rat or to the loss of MPNc neurons in the control female. Pregnant, female Sprague‐Dawley rats were given an injection of [3H]methyl thymidine on embryonic day 18 (E18). Rats were exposed to testosterone propionate (TP) or vehicle from E20 to postnatal day 10 (PN10) or until the time of sacrifice. Pups from three groups [males (oil), females (oil), and sex‐reversed females (TP)] were sacrificed on PN2, PN4, PN7, PN10, or PN30. The volume of the compact part of the MPNc increased in males and sex‐reversed females after PN4 but the volume in the nucleus of females remained relatively constant. The number of neurons and [3H]thymidine‐labeled cells remained elevated from PN2–PN30 in males or sex‐reversed females but decreased dramatically in oiltreated females between PN4 and PN7, reaching a minimal number by PN10. Cell cross‐sectional area increased with age while cell density decreased. These observations are consistent with the hypothesis that the lack of growth of the compact part of the MPNc of the female is due to a loss of neurons while the increase in volume of the male's nucleus is due at least in part to growth of its constituent neurons. © 1993 John Wiley & Sons, Inc.
Hippocampal growth cone responses to focally applied electric fields
Authors: Davenport Roger W. , McCaig Colin D. 
Published: January 2005

AbstractA wide variety of cell types respond to electric fields in culture. Despite evidence for electric fields existing in the mammalian embryo, there are few studies testing the effects electric fields exert on neurons from the mammalian central nervous system (CNS). The present study demonstrates orientation responses to focally applied electric fields of embryonic rat hippocampal neurons isolated in culture. The most striking result from this study is that different growth cones of the same neuron can show differential responsiveness to focally applied electric fields: growth cones on the short straight processes that are destined to become dendrites, oriented toward the cathode, whereas growth cones on the longest process, the presumptive axon, did not orient. The present experiments bring a significant increase in resolution to the study of neuronal growth cone orientation by applied electric fields: a novel examination of the early events leading to orientation. Growth cones on dendrites displayed a spectrum of orientation responses: directed lamellipodial extension, directed filopodial extension and/or reorientation, cytoplasmic swelling of existing filopodia, consolidation of filopodia, and rapid elongation of the entire process. Individual growth cones displayed only one or two of these responses. Additionally, not all growth cones on these short processes sustained their initial orientation response: 35% adapted within 6 min. © 1993 John Wiley & Sons, Inc.
A comparison of the development of neuropeptide and MAP2 immunocytochemical labeling in the macaque visual cortex during pre‐ and postnatal development
Authors: Mehra Raj D. , Hendrickson Anita E. 
Published: January 2005

AbstractThe appearance of Substance P (SP) and Neuropeptide Y (NPY) has been studied using light microscopic immunocytochemical labeling throughout the complete developmental span of Macaca nemestrina monkey striate cortex. In the adult, 80% of the NPY + neurons occur in the white matter (WM) and most of the remainder are medium to large multipolar neurons in layer 2. Fibers occur in all layers except 4C and are very numerous, given the relatively small number of NPY+ cell bodies. NPY+ neurons first were seen at embryonic day (E) 75. Most neurons were in the intermediate zone (IZ), but a few were in the immature cortical plate (CP). An adultlike distribution was present by E125 for neurons and by birth for fibers, but fiber staining intensity and number increased to postnatal year 1 (P1yr). In adult cortex, numerous SP+ nonpyramidal neurons were present in layers 2–6 and WM, but SP+ fibers were surprisingly infrequent. During development, significant numbers of SP+ neurons were not seen in the CP until E113–125. Later prenatal ages had a prominent plexus of SP+ cell bodies and fibers at the layer 5/6 border. This plexus disappeared by P12wk due to either down‐regulation of SP or cell death. SP+ neurons in IZ/WM were very sparse until birth after which they increased in number and staining intensity up to P1yr, suggesting a postnatal up‐regulation of SP in a preexisting WM subpopulation. Cell densities were determined for SP, NPY, and the neuron‐specific marker microtubule‐associated protein 2 (MAP2) to clarify the developmental dynamics of IZ/WM neurons. MAP2+ cell densities in WM peaked around birth and then declined 20% in the outer half and 77% in the inner half of WM. SP+ cell density rose 57% from birth to P20wk and then declined 20% into adult hood. NPY+ cell density was fairly constant prenatally and then rose 300% by adulthood. Neuropeptide cell density changes took place predominatly in the outer WM. These data indicate that cell death does occur in the general population of monkey striate cortical WM neurons. In contrast, both SP+ and NPY+ cells are characterized by minimal cell death and a late expression of neuropeptides which causes an increase in neuropeptide+ cell density in postnatal WM. © 1993 John Wiley & Sons, Inc.
Effects of a protein synthesis inhibitor on the hormonally mediated regression and death of motoneurons in the tobacco hornworm, Manduca sexta
Authors: Weeks Janis C. , Davidson Seana K. , Debu Bettina H. G. 
Published: January 2005

AbstractThe larval–pupal transformation of Manduca sexta is accompanied by the loss of the abdominal prolegs. The proleg muscles degenerate, the dendritic arbors of proleg motoneurons regress, and a subset of the proleg motoneurons dies. The regression and death of proleg motoneurons are triggered by the prepupal peak of ecdysteroids in the hemolymph. To investigate the possible involvement of protein synthesis in these events, we gave insects repeated injections of the protein synthesis inhibitor, cycloheximide (CHX), during the prepupal peak. Examination of insects 3–5 days following CHX treatment showed that CHX inhibited the death of proleg motoneurons and the production of pupal cuticle in a dose‐dependent fashion. When insects were allowed to survive for 10 days after the final CHX injection, motoneuron death and pupal cuticle production sometimes occurred belatedly, apparently in response to the ecdysteroid rise that normally triggers adult development. CHX treatments that inhibited motoneuron death were less effective in inhibiting dendritic regression in the same neurons. In another set of experiments, abdomens were isolated from the ecdysteroid‐secreting glands prior to the prepupal peak, and infused with 20‐hydroxyecdysone (20‐HE). Single injections of CHX delivered just prior to the start of the 20‐HE infusion inhibited motoneuron death and pupal cuticle production, but in the range of doses tested, did not prevent dendritic regression. Our findings suggest that protein synthesis is a required step in the steroid‐mediated death of proleg motoneurons, and that dendritic regression is less susceptible to inhibition by CHX than is motoneuron death. © 1993 John Wiley & Sons, Inc.
Distribution of pluripotent neural crest cells in the embryo and the role of brain‐derived neurotrophic factor in the commitment to the primary sensory neuron lineage
Authors: Sieber‐Blum Maya , Ito Kazuo , Richardson Michael K. , Langtimm Carol J. , Duff R. Scott 
Published: January 2005

AbstractMany early migratory neural crest cells are pluripotent in the sense that their progeny are able to generate more than one differentiated phenotype (Sieber‐Blum and Cohen, 1980, Dev. Biol. 80:95–106; Baroffio, Dupin, and Le Douarin, 1988, Proc. Natl. Acad. Sci. USA 85:5325–5329; Bronner‐Fraser and Fraser, 1988, Nature 335:161–164; Sieber‐Blum, 1989a, Science 243:1608–1611; Ito and Sieber‐Blum, 1991, Dev. Biol. 148:95–106). At trunk levels, the neural crest contains two classes (Sieber‐Blum and Cohen, 1980) and at posterior rhombencephalic levels, three different classes of pluripotent cells (Ito and Sieber‐Blum, 1991). We investigated cell differentiation by in vitro clonal analysis to determine when in development the pool of pluripotent neural crest cells becomes exhausted. The data suggest that different classes of pluripotent cells, precursor cells with more restricted developmental potentials, and apparently committed cells, exist at sites of advanced migration (posterior branchial arches) and even at target sites of neural crest cell differentiation [posterior branchial arches, dorsal root ganglia (DRG), sympathetic ganglia (SG), and epidermal ectoderm]. Some putative classes of pluripotent cells persist well into the second half of embryonic development. These observations have implications for our understanding of the mechanisms that control neural crest cell migration and differentiation. They support the idea that cues originating from the microenvironment affect differentiation of pluripotent neural crest cells. One such signal appears to be brain‐derived neurotrophic factor (BDNF). In the presence of BDNF, but not nerve growth factor (NGF), there is a significant increase in the number of neural crest cells per colony that express a sensory neuron‐specific marker. Because this increase is not accompanied by a corresponding increase in the total number of cells per colony, this suggests that BDNF plays a role in cell type specification. © 1993 John Wiley & Sons, Inc.
Cell interactions that determine sympathetic neuron transmitter phenotype and the neurokines that mediate them
Authors: Rao M. S. , Landis S. C. 
Published: January 2005

AbstractThe transmitter properties of both developing and mature sympathetic neurons are plastic and can be modulated by a number of environmental cues. Cell culture studies demonstrate that noradrenergic neurons can be induced to become cholinergic and that the expression of neuropeptides can be altered. Similar changes in transmitter phenotype occur in vivo. During development, noradrenergic neurons that innervate eccrine sweat glands acquire cholinergic and peptidergic function. This change is dependent upon interactions with the target tissue. Following injury of sympathetic neurons in developing and adult animals, striking alterations take place in peptide expression. Ciliary neurotrophic factor and cholinergic differentiation factor/leukemia inhibitory factor, members of a family that includes several hematopoeitic cytokines, induce cholinergic function and modulate neuropeptide expression in cultured sympathetic neurons. Studies in progress provide evidence that members of this new cytokine family influence the transmitter phenotype of sympathetic neurons not only in vitro but also in vivo. © 1993 John Wiley & Sons, Inc.
Spatial integration among cells forming the cranial peripheral nervous system
Authors: Noden Drew M. 
Published: January 2005

AbstractNeural crest cells represent a unique link between axial and peripheral regions of the developing vertebrate head. Although their fates are well catalogued, the issue of their role in spatial organization is less certain. Recent data, particularly on patterns of expression of Hox genes in the hindbrain and crest cells, have raised anew the debate whether a segmental arrangement is the basis for positional specification of craniofacial epithelial and mesenchymal tissues or is but one manifestation of underlying spatial programming processes. The mechanisms of positional specification of sensory neurons derived from the neural crest and placodes are unknown. This review examines the spatial organization of cells and tissues that develop in proximity to sensory neurons; some of these tissues share a common ancestry, others are targets of cranial sensory and motor nerves. All share the necessity of acquiring and expressing site‐specific properties in a functionally integrated manner. This integration occurs in part by coordinating patterns of cell migration, as occurs between migrating crest cells and branchial arch myoblasts. Constant rostro‐caudal relations are maintained among these precursors as they move dorsoventrally from the hindbrain–paraxial regions to establish branchial arches. During this period the interactions among these and other mesenchymal cells are hierarchical; each cell population differentially integrates its past with cues emanating from new microenvironments. Analyses of tissue interactions indicate that neural crest cells play a dominant role in this scenario. © 1993 John Wiley & Sons, Inc.
Antiserum to an eye‐specific protein identifies photoreceptor and circadian pacemaker neuron projections in Aplysia
Authors: Strack Stefan , Jacklet Jon W. 
Published: January 2005

AbstractThe marine gastropod Aplysia has a circadian clock in each eye that generates a circadian rhythm of optic nerve activity. The axons of pacemaker neurons carry the rhythmic activity to the brain where it can be recorded from various ganglionic connectives as it is distributed throughout the CNS. We had previously identified an eye‐specific 48‐kD protein using an antiserum, anti‐S, that recognizes the period gene product of Drosophila. We have now obtained two partial amino acid sequences of the 48‐kD protein and raised a polyclonal antiserum using a synthetic peptide with the amino acid sequence of one of them. The antiserum recognizes a family of spots of Mr 47–48 kD and Pi 5.9–6.0 on 2D immunoblots of eye proteins. The immunoblot staining intensity does not exhibit a circadian rhythm. Used in immunocytochemistry, the antiserum recognizes fibers in the optic nerve and retinal neuropil, pacemaker neurons, certain photoreceptors, and the photoreceptor rhabdom layer. It stains the optic nerve fibers and optic fiber terminals in the cerebral optic ganglion and recognizes the cerebral optic tracts, putative synaptic exchange areas, and optic tract projections from the cerebral ganglion into various head nerves and interganglionic connectives. The function of the 48‐kD protein is not known but it could be involved in the maintenance or regulation of the retinal afferent pathways, including the pacemaker neuron axons, known from previous axonal transport and electrical recording studies to be the circadian output pathway. © 1993 John Wiley & Sons, Inc.
Ecdysteroid regulation of olfactory protein expression in the developing antenna of the tobacco hawk moth, Manduca sexta
Authors: Vogt Richard G. , Rybczynski Robert , Cruz Manuel , Lerner Michael R. 
Published: January 2005

AbstractDuring adult metamorphosis, the moth olfactory neurons and their glia‐like support cells pass through a coordinated and synchronous development. By 60% of development, the olfactory system is anatomically complete, but functional maturation does not occur until about 90% of development. Maturation is characterized by the onset of odorant sensitivity in the sensory neurons and the expression of certain antennal‐specific proteins including odorant binding proteins (OBPs) and odorant degrading enzymes (ODEs). The OBPs have been cloned and sequenced, and are thus useful models for investigating the molecular mechanisms coordinating final maturation of the developing olfactory system. The ecdysteroid hormones have been observed to regulate many cellular level neuronal changes during adult metamorphosis. In particular, the late pupal decline in ecdysteroids is known to influence programmed death of nerves and muscles at the end of metamorphoses. Experiments are presented here which indicate that this decline in ecdysteroids also induces the expression of the OBPs. Normal OBP expression occurs 35–40 h before adult emergence. In culture, OBP expression could be induced at least 90 h before adult emergence by the premature removal of ecdysteroid. This premature expression was blocked by culturing tissue in the presence of the biologically active ecdysteroid 20‐hydroxyecdysone. These findings suggest that maturation of the olfactory system is regulated by the decline in ecdysteroids, and support the view that olfactory development, in general, may be coordinated by chaging levels of pupal ecdysteroids. © 1993 John Wiley & Sons, Inc.