bluuebunny/crossref_metadata_2025_split huggingface dataset:
Colocalization of tyrosine hydroxylase and Fos in the male Syrian hamster brain following different states of arousal
Authors: Asmus Stephen E. , Newman Sarah Winans 
Published: January 2005

AbstractIn an investigation of the role that central tyrosine hydroxylase‐(TH) containing neurons play in copulation in the male Syrian hamster, The induction of Fos protein was used as an index of neuronal activation. With a double immunoperoxidase technique, the activation of TH neurons was compared in hamsters from three experimental groups: (1) mated in a new cage; (2) handled controls placed in a new cage, and (3) unhandled controls. Although mating selectively induces Fos production in the medial amygdaloid nucleus (Me), more than half of the TH neurons in Me (a region outside of the classical catecholamine systems) expressed Fos equally in all of the experimental groups. In the paraventricular hypothalamic nucleus (PVN), TH neurons were activated equivalently in mated and handled control animals compared to unhandled controls. TH neurons in the neucleus of the solitary tract (NST) were also activated in handled control animals, and mating further enhanced the level of Fos immunostaining in these neurons above both groups of nonmated animals. Although not quantified, co‐localization of Fos and TH was also observed in all experimental groups in the olfactory bulbs and the interfascicular nucleus, and in the horizontal limb of the diagonal band of Broca and the cerebral cortex, regions which contain TH neurons but are not part of the classically described TH cell groups. Few, if any, TH neurons in other catecholaminergic brain regions, such as the substantia nigra and locus coeruleus, produced Fos in any of the experimental groups. These results suggest that TH neurons in the PVN and NST may be activated during different states of arousal, and that nonclassical TH neurons in the amygdala produce high levels of Fos even in unstimulated animals. 1994 John Wiley & Sons, Inc.
Neurite outgrowth from cultured CNS neurons is promoted by inhibitors of protein and RNA synthesis
Authors: Louis Jean‐Claude , Burnham Patricia , Varon Silvio 
Published: January 2005

AbstractWe examined the effects of changes caused by the blocking of protein and RNA synthesis on neurite outgrowth from neurons of the central nervous system (CNS) in primary culture. Exposure to cycloheximide and actinomycin‐D led to dramatic increases in the length of neurites in cultures of neurons from various rat or chick CNS regions. Inhibitor‐induced neurite outgrowth was observed (1) from dopaminergic neurons in mixed cultures of the rat substantia nigra or (2) in pure cultures of rat and chick neurons grown on a polyornithine/laminin substratum. These results suggest that neurite outgrowth from CNS neurons is kept restricted, at least in culture, by the continuous production of a labile neurite‐inhibiting protein intrinsic to the neurons, which rapidly decays following inhibition of protein or RNA synthesis. 1994 John Wiley & Sons, Inc.
Divergent axon collaterals originate in the estrogen receptive ventromedial nucleus of hypothalamus in the rat
Authors: Akesson Thomas R. , Ulibarri Catherine , Truitt Sharon 
Published: January 2005

AbstractThe ventromedial nucleus of the hypothalamus (VMH) plays a crucial role in the mediation of lordosis by integrating predominantly inhibitory limbic signals with cyclic variation of ovarian steroids and sending a stimulatory output to the midbrain, especially the periaqueductal gray (PAG). Tract‐tracing studies have established projections of the VMH and Golgi studies have shown these neurons to frequently give rise to axon collaterals, but the anatomical pattern of shared projections has not been explored. We have used a combination of retrograde tracers to map VMH projections to the medial division of the medial preoptic nucleus (MPNm), posterodorsal division of the medial nucleus of the amygdala (MeApd), and the PAG. Neurons with dual projections were mainly confined to the VMHvl and represented 31%–37% of each projection subset. Neurons simultaneously projecting to the MPNm, MeApd, and PAG represented 7%–9% of each projection subset. By combining tract‐tracing with steroid autoradiography, we found that approximately one‐quarter of each projection subset in the VMHvl concentrated 3H‐estradiol. Thus, some of the VMHvl neurons that communicate a facilitatory signal to the PAG may also act to stimulate lordosis through a feedback suppression of the net inhibition formed by efferent signals from the forebrain. The even distribution of estrogen binding among projection subsets suggests a lack of compartmentalization of estrogen‐regulated processes that are relevant to lordosis. 1994 John Wiley & Sons, Inc.
Glutamate receptor binding in juvenile and adult Rana pipiens CNS
Authors: Cline Hollis T. , McDonald J. W. , Constantine‐Paton Martha 
Published: January 2005

AbstractAutoradiographic methods were used to map NMDA and quisqualate‐sensitive glutamate binding sites in the brain of mature and juvenile Rana pipiens frogs. NMDA and quisqualate‐sensitive sites were consistently co‐localized in the CNS. The highest glutamate binding occurred in the telencephalon, hypothalamus, and cerebellum. Glutamate binding sites were also specifical neuropil of the optic tectum, consistent with glutamate being the retinal ganglion cell neurotransmitter. The distribution of glutamate binding sites in the brain of juvenile postmate morphic frogs was similar to that in adults. In general, Quis binding increased about twofold in adults compared to juveniles, whereas NMDA binding did not show a comparable developmental increase. To test whether glutamate binding sites are located on retinal axon terminals or on tectal cell dendrites in the optic tectum, juvenile postmetamorphic frogs were enucleated unilaterally, and receptor binding was performed following 1, 3, 7, and 14 days survival. The denervated tectal neuropil showed a delayed decrease in NMDA‐and quiequalate‐sensitive binding, consistent with the receptors being located on postsynaptic tectal cell dendrites. © 1994 John Wiley & Sons, Inc.
Expression of trkC receptor mRNA during development of the avian nervous system
Authors: Kahane Nitza , Kalcheim Chaya 
Published: January 2005

AbstractNeurotrophin‐3 (NT‐3) has mitogenic and neurogenic activities on distinct central and peripheral nervous system (CNS and PNS) progenitors in avian embryos. It was therefore important to characterize in detail the expression pattern of TrkC, a high‐affinity receptor for NT‐3, during nervous system ontogeny. We report that trkC‐encoding transcripts are expressed in the CNS primordium in several spatiotemporal distinct waves. trkC mRNA becomes evident in the dividing neuroepithelium where it is expressed homogeneously. A subsequent enhancement of the signal in dorsal areas of the neural tube occurs concomitant with the migration of neural crest cells from the CNS. Expression of trkC mRNA is then reduced in the germinal epithelium while progressively appearing on postmitotic neurons at the periphery of the neural tube. At a time preceeding the onset of normal motoneuron death, trkC signal is transiently undetectable in the ventral third of the neural tube. Diffuse expression in the spinal cord is resumed on embryonic day (E) 7. Subsets of premigratory and migrating neural crest progenitors also express the trkC receptor. Intense trkC signal is then evident throughout the newly organizing dorsal root ganglia (DRG), and becomes later restricted to defined postmitotic neuronal populations. Cranial ganglia also express the trkC gene from early stages of gangliogenesis. Furthermore, whereas the primary sympathetic ganglia show trkC mRNA, in the secondary ganglia a barely detectable signal could be observed. The dynamic up‐and down‐regulations of trkC reported here to occur both in the CNS and PNS primordia correspond to diverse, though only partially known, developmental processes. Taken together, these results support the notion that the NT‐3–TrkC complex mediates diverse functions during neural development. © 1994 John Wiley & Sons, Inc.
Sequencing and promoter analysis of the genomic region between the rat neuronal nicotinic acetylcholine receptor β4 and α3 genes
Authors: Boyd R. Thomas 
Published: January 2005

AbstractNicotinic acetylcholine receptors (nAChRs) found on neurons are composed of ligand binding (α) and structural (β) subunits. Different combinations of α and β subunits produce nAChR subtypes with different pharmacological and ion‐conducting proeprties. Transcriptional regulation may be an important determinant of receptor subtype in a neuronal population and thus influence transmission through a ganglion or group of neurons in the CNS by controlling the nAChR subtype (s) present. In order to understand the transcriptional regulation of neuronal nAChRs by cell contact and electrical activity, it will be first necessary to identify DNA elements that control the expression of memebrs of this family and to identify factors required for the expression of these genes. In this report we have begun to examine the 5′‐ flanking region of one member of the nAChR family of genes, α3. We have sequenced the region between the β4 and α3 genes and have identified two promoter regions in the β4‐α3 intergenic region. One region is close to the β4 gene downstream of exon 6 and has strong promoter activity in both orientations; the other is close to the start of the α3 gene coding region. A region with putative silencer acitivity is also found near the upstream promoter. This bidirectional promoter region could be involved in the control of α3 and β4 gene expression. 1994 John Wiley & Sons, Inc.
Sexual differentiation in the CNS of the moth, Manduca sexta. I. Sex and segment‐specificity in production, differentiation, and survival of the imaginal midline neurons
Authors: Thorn Robert S. , Truman James W. 
Published: January 2005

AbstractWe analyzed the development of several sets of postembryonic sex‐specific motoneurons in Manduca sexta which belong to a group of homologous lineage of neurons called the imaginal midline neurons (IMNs). Adult female oviduct motoneurons and male sperm duct motoneurons are IMNs that show similar anatomical features and differentiate during metamorphosis, despite appearing in different segments: A7 for oviduct neurons, A9 for sperm duct neurons. These cells are born at the same time and, initially, similar sets are found in A7 and A9 ganglia of larvae of both sexes. The dimorphic adult pattern is generated by sex‐specific production and cell death. A7 IMNs differentiate in both sexes through early pupal stages, whereupon they disappear in the male and become the oviduct motoneurons in the female. A9 IMNs are overproduced in the male, and subsequent cell death reduces male cell number and eliminates the small complement of female cells; the surviving male cells develop into the sperm duct motoneurons. Similar IMN arrays are generated in nongenital ganglia, but show non‐sex‐specific fates. This suggests that both the sex of these cells and their segment of residence play major roles in their subsequent differentiation. 1994 John Wiley & Sons, Inc.
Neural organization of the ventilatory activity in the frog, Rana catesbeiana. I
Authors: Kogo Naoki , Perry Steven F. , Remmers John E. 
Published: January 2005

AbstractIn order to elucidate the neural basis for lung ventilation in the frog, we have investigated the efferent neural activity to oropharyngeal muscles in the decerebrate, paralyzed, unanesthetized bullfrog, Rana catesbeiana. Efferent motor output was recorded from the mandibular branch of the trigeminal (Vmd), the laryngeal branch of the vagus (Xl), and the main and sternohyoid branches of the hypoglossal nerve (Hm and Hsh, respectively). Two types of rhythmic bursting outputs were observed: (1) a high‐frequency, low‐amplitude, reciprocal oscillation between Vmd, a buccal levator nerve, and Hsh, a buccal depressor nerve; and (2) a low‐frequency, high amplitude, synchronous bursting of Vmd, Hm, Hsh, and Xl. The first type is inferred to represent fictive oropharyngeal ventilation. The second type of burst was divided into four intervals: (a)augmenting acitivity of Hsh; (b) activation of Xl with continued activation of Hsh; (c) activation of Vmd and Hm (a buccal levator nerve), continued activation of Xl, and termination of Hsh activity; and (d) waning activity in Vmd and Hm associated with a prominent second wave in Xl. This coordinated activity is inferred to represent fictive pulmonary ventilation because the neurograms in these four intervals correspond closely EMGs and neurograms recorded in the intact frog during the four phases of pulmonary ventilation, namely, buccal depression, pulmonary expiration, pulmonary inspiration, and glottal closure. Hypercapnia, vagotomy, and cutaneus pinching enhanced the high‐amplitude, low‐frequency rhythm, but not the low‐amplitude, high‐frequency oscillation. Lung inflation generally inhibited the former and not the latter, but in some cases lung inflation stimulated pulmonary ventilation. We conclude that oropharyngeal and pulmonary ventilation of the frog are produced by one or, possibly, two intrinsically active generators. 1994 John Wiley & Sons, Inc.
The TRH neuronal phenotype forms embryonic cell clusters that go on to establish a regionalized cell fate in forebrain
Authors: Hayes William Pär 
Published: January 2005

AbstractHow neurons diversify in developing brain to produce discrete cell fates in their appropriate regions remains a fundamental question. Embryonic Xenopus was previously used to identify juxtaposed embryonic cells that first express proopiomelanocortin mRNA in forebrain and pituitary, supporting the idea that this neuropeptide phenotype is induced locally. (Hayes and Loh, 1990, Development 110:747–757). To begin to examine how a more widespread population of forebrain cells is set up, the present focus is on the thyrotropin‐releasing hormone (TRH) phenotype. Serial section in situ hybridization histochemistry produced the unexpected finding that the adult‐like TRH system spanning forebrain and comprising over six different telencephalic and diencephalic nuclei, is preceded by an embryonic TRH cell population that is initially localized and then highly regionalized in the area from which the adult pattern develops. Thus, the first TRH cells, detected in vivo after 35 h (stage 29/30), were confined to discrete anterior or posterior bilateral clusters in embryonic forebrain or hindbrain. Thereafter, the TRH cell clusters in diencephelon, but not hindbrain, expanded to form rows, extending anteriorly into telencephalon and bifurcating posteriorly around the infundibulum. By 80 h (stage 42), after extensive brain morphogenesis, these forebrain rows showed regional differences in levels of TRH and mRNA corresponding to the specific brain nuclei that have been shown to contain TRH cells in adult. These findings show that subsets of phenotype‐specific forebrain cell first form a regionalized neuronal cell fate before distinct brain nuclei form. This is turn points to the testable hypothesis in Xenopus that certain neuronal cell fates in forebrain may be dictated by cell lineage or local induction. 1994 John Wiley & Sons, Inc.
Neuronal differentiation of PC12 cells as a result of prevention of cell death by bcl‐2
Authors: Sato Noboru , Hotta Kazuhiko , Waguri Satoshi , Nitatori Tohru , Tohyama Koujiro , Tsujimoto Yoshihide , Uchiyama Yasuo 
Published: January 2005

AbstractRat pheochromocytoma PC12 cells die when cultured in serum‐free medium. Neurotrophic factors can rescue PC12 cells from cell death, and induce neuronal differentiation. To further investigation the relationship among cell death, survival, and differentiation, the bcl‐2 cDNA, which is known to prevent apoptosis in various types of cells, was transfected into PC12 cells. Six monoclonal bcl‐2‐transfected cell lines were isolated and confirmed to express mRNA and protein product of bcl‐2. The wild‐type and bcl‐2‐transfected PC12 cells were kept to adhere to collagen‐coated dishes at the inintiation of serum‐free experiments to avoid cellular damage due to detachment of the cells by triturtion. Even under the conditions, the control PC12 cells mostly died within 24 h, when cultured in serum‐free medium whereas those expressing Bcl‐2 survived even for 7 days in serum‐free medium. Moreover, outgrowth of long processes in thebcl‐2‐transfected cells was only observed under the condition to keep the cells attached to the dishes in serum‐free medium without any additive neurotrophic or growth factors. Neurofilament medium protein, which is a neuron‐specific cytoskeletal component, was also expressed in the differentited cells, suggesting that the long processes in bcl‐2‐transfected PC12 cells are neurites. However, neuronal differentiation of PC12 cells expressing Bcl‐2 was not observed when cultured in serum‐containing medium. Accordingly, survival of PC12 cells expressing Bcl‐2 under the condition which cells usually die may be accompanied with neuronal differentiation. 1994 John Wiley & Sons, Inc.
Neutrophic influence of denervated sciatic nerve of on adult dorsal root ganglion neurons
Authors: Kuffler Damien P. , Megwinoff Olga 
Published: January 2005

AbstractIsolated adult frog dorsal root ganglion neurons survive in vitro in a defined medium for more than 4 weeks and extend processes. When co‐cultured with a 1‐mm piece of peripheral nerve the average tottal process lenght per neuron was 10 times longer than that of control neurons by 8 days, and the processes had a significantly different morphology from that of control neurons. This influence on process length increased with increasing time of nerve denervation length increased with increasing time of nerve denervation prior to co‐culturing. These results suggest the release of a neurotrophic factor/s from the cells of the peripheral nerve. The neurotropic influence was completely blocked by antibodies against mouse nerve growth factor (NGF). Although NGF increased the average process length by twofold over control neurons, its influence never reached that of the nerve‐released factor, and the NGF‐induced processes had a distinctly different morphology. The frog nerve‐released factor promoted process outgrowth from E11 chick sympathetic ganglia, although the process number, length, and their fasciculation differed greatly from those induced by NGF. These results suggest that the nerve‐released factor/s are immunologically and functionally related to NGF but have not estabished whether a single factor or an aggregate of several secreted molecules are responsible. This article presents a new preparation in which the varied influences of different neurotrophic factors can be studied in great detail on large populations of isolated adult vertebrte neurons and sets the stage for the characterization and isolation of the frog peripheral nerve neurotrophic factor, as well as examining the influence of this facor on neuronal morphology and its ability to direct process outgrowth. 1994 John Wiley & Sons, Inc.
Expression of the ligand‐binding nicotinic acetylcholine receptor subunit Dα2 in the Drosophila central nervous system
Authors: Jonas Petra E. , Phannavong Bounpheng , Schuster Renate , Schröder Christiane , Gundelfinger Eckart D. 
Published: January 2005

AbstractThe Dα2 gene encodes a ligand‐binding subunit of nicotinic acetylcholine receptors (nAChRs) from Drosophila melanogaster. We have studied the distribution of Dα2 transcripts and protein by in situ hybridization and immunohistochemistry, respectively, as well as the regulation of Dα2 gene expression in vivo using Dα2 promoter fragments fused to the Escherichia coli lacZ gene. transcripts and protein from the Dα2 gene were detected exclusively in the central nervous system. Both in late embryos and adults Dα2‐like immunoreactivity is widely but not uniformly distributed in the synaptic neuropil, suggesting that the Dα2protein is a subunit of a synaptic nicotinic receptor. Its. distribution resembles that of ALS and ARD protein, two other nAChR subunits of the fly. Five different Dα2‐lacZ fusion gene constructs were introduced into theDrosophila genome by P‐element–mediated gene transfer to identity functional elements of the Dα2 promoter. All constructs produce a basic lacZ expression pattern that is compatible with the distribution of Dα2 transcripts and protein. A 880 bp upstream fragment harbors the cis elements for the expression of a weak but specific basic Dα2 pattern. The next 350 bp further upstream significantly enhance β‐galactosidase expression without influencing the pattern of expression. Between 1.7 and 7.3 kb upstream of the transcription start site one or more elements that are required for Dα2 expression in optic lobe tangential cells are located. 1994 John Wiley & Sons, Inc.
Outgrowth morphology and intracellular calcium of crustacean neurons displaying distinct morphologies in primary culture
Authors: Graf Robert A. , Cooke Ian M. 
Published: January 2005

AbstractPeptidesecreting neurons from crustacean X‐organ regenerating in defined culture possess different ionic current profiles correlated with two distinct morphological types, veiling and branching; voltage‐dependent Ca2+ current is prominent in neurons consistently extending large veils, but is small in neurons that repetitively branch. Intracellular free calcium ([Ca2+]i) have been implicated in regulation of neurite outgrowth underlying the establishment of distinct morphologies. Here, basal [Ca2+]i was measured by fura‐2 fluorescence ratio imaging from these morphologically distinct neurons and compared. Both morphological tapes can extend out processes over a [Ca2+]i range (approximately 50 to 300 nM) that is much greater than that reported for neurons of other phyla. Application of high k+ saline led to increases in [Ca2+]i in soma, neurite, and lamellipodium of veiling neurons. Increase were great for veiling than branching neurons. These observations were consistent with the previous voltage clamp data for calcium currents. Media altered to perturb [Ca2+]i were used to assess the role of [Ca2+]i in veiling or branching outgrowth programs. Outgrowth of veiling cells was arrested addition of 100 μMCD2+, a calcium channel blocker. Outgrowth resumed following brief exposures to Cd2+. Branching neurons were unaffected by Cd2+. Cd2+ at lower levels (10 μM) had no effect on outgrowth of either neuronal type, whereas at higher levels (1 mM), outgrowth of both types was arrested. Reduction of extracellular sodium to 0.001 of normal concentration stopped veiling outgrowth, but branching outgrowth continued, although it was less robust. Addition of tetrodotoxin (1 μM) did not alter outgrowth of either neuronal type relative to controls. Thus, peptidergic neurons of differing intrinsic morphologies maintain similar basal [Ca2+]i levels under identical culture conditions, yet show differing sensitivities to manipulations influencing [Ca2+]i with respect to regenerative outgrowth, but not its form. 1994 John Wiley & Sons, Inc.