bluuebunny/crossref_metadata_2025_split huggingface dataset:
Localization of immunoreactive ubiquitin in the nervous system of the Manduca sexta moth
Authors: Fahrbach S. E. , Schwartz L. M. 
Published: January 2005

AbstractSelective neuronal death is a normal component of metamorphosis in the moth, Manduca sexta. In particular, the three unfused abdominal ganglia of the ventral nerve cord serve as a useful experimental preparation in which to study the regulation of the molecular mechanisms that mediate programmed cell death. Ubiquitin, a highly conserved 76‐amino acid protein found in all eukaryotic cells, has previously been shown to be present in increased amounts in some tissue undergoing programmed cell death (e. g., larval intersegmental muscles inManduca sextamoths, dying cells in developing tunicates), but not in others (T‐cells, Drosophila ommatidial cells, cultured sympathethic neurons deprived of nerve growth factor). It has been hypothesized that the need for ubiquitin‐dependent proteolysis is increased in dying cells, and that the accumulation of ubiquitin might serve as an early marker for cells commited to die. Immunohistochemical localization of ubiquitin at the light microscopic level in the adbominal gaglia of Manduca sextasuggests that this protein plays a number of important roles in neuronal physiology and may be associated with the death of some neurons in this tissue. The most intense staining of neuronal cytoplasm, however, was found not in dying neurons, but instead in sets of persisting neurons that may serve a primarily neurosecretory or neuromodulatory function. The staining obtained in these cells with antibodies directed against ubiquitin was developmentally regulated. © 1994 Wiley‐Lisx, Inc.
Monoamine receptors in the amygdaloid complex of the tree shrew (Tupaia belangeri)
Authors: Flügge Gabriele , Ahrens Olaf , Fuchs Eberhard 
Published: January 2005

AbstractAlthough it is well known that the mammalian amygdala comprises a heterogeneous complex of cytoarchitectonically and histochemically distinct nuclei, the association of these nuclei with different monoamine systems has not been described in detail. We therefore investigated the pattern of receptors for monoamines in the amygdala of the tree shrew (Tupaia belangeri). Binding sites for the α2‐adrenoceptor ligand (3H) rauwolscine, the α1‐adrenoceptor ligand (3H) prazosin, the β‐adrenoceptor ligand (125I) iodocyanopindolol, and the serotonin1A‐receptor ligand (3H) 8‐hydroxy‐2 (di‐n‐propylamino) tertralin were visualized by in vitro autoradiography, and anatomically localized by comparing the autoradiograms to Nissl‐ and acetylcholinesterase‐stained sections. To characterize binding of the radioligands pharmacologically, displacement experiments with different specific competitors were performed.Whereas the highest number of α2‐adrenergic binding sites was detected in the medial and the central nucleus as well as in the intercalated nueclei, the majority of serotonin1A binding sites was found in the magnocellular basal nucleus and the accessory basal nucleus, demonstrating a clear difference in the anatomy of the α2‐adrenergic and the serotonin1A receptor systems. In contrast, the pattern of α1‐adrenoceptor binding partially overlaps with that of both former receptor types. While the number of α‐adrenergic and serotonin1A binding sites is relatively high in the tree shrew amygdala, there is only a low number of β‐adrenergic binding sites in most nuclei. However, in the cortical nuclei, moderate to high numbers of binding sites for all radioligands are present. Therefore, according to our data on the tree shrew amygdala, which is anatomically similar to the amygdala of cats and primates, α2‐adrenoceptors cover primarily the medial part of the amygdaloid formation and serotonin1A‐receptors predominantly occupy the basal nuclei, whereas α1‐adrenoceptors are present in both parts of the formation. © 1994 Wiley‐Liss, Inc.
Synaptic organization of regenerated retina in the goldfish
Authors: Hitchcock Peter F. , Cirenza Paul 
Published: January 2005

AbstractIn the adult goldfish, any manipulation that significantly depletes retinal neurons stimulates neurogenesis and the regeneration of nearly normal retina. We sought to determine the extent to which the regenerated neurons formed normal synaptic connections. We used qualitative and quantitative electron microscopy to compare the organization of the synaptic layers in regenerated and normal retinas. In eight eyes, a small patch of retina was surgically excised, stimulating regeneration of new retina in its place. Animals were killed 16–20 weeks after surgery. Qualitative comparisons of the synaptic architecture of photoreceptor terminals in the outer plexiform layer and quantitative comparisons of the synaptic organization in the inner plexiform layer were made between the patch of regenerated retina and an adjacent intact site. In the regenerated outer plexiform layer, cone pedicles and rod spherules were not arranged as regularly as normal, but they formed normal‐appearing synaptic contacts. In the regenerated inner plexiform layer, with one exception, the quantitative descriptors of the synaptic organization in the normal and regenerate were n ot significantly different: The planimetric and numerical densities of the synapses, number of synapses/inner retinal neuron, and, with the exception of the bipolar terminals in the inner plexiform layer, and synapse depth profiles were similar. These data suggest that (1) relatively normal synaptic connections are recreated during regeneration, (2) the cellular mechanisms that guide synaptogenesis during development act during retinal regeneration, and (3) the physiological response properties of regenerated neurons should be comparable to that found in the normal retina. © 1994 Wiley‐Liss, Inc.
Distribution of the postsynaptic dorsal column projection in the cuneate nucleus of monkeys
Authors: Cliffer Kenneth D. , Willis William D. 
Published: January 2005

AbstractCells in the spinal cord that are postsynaptic to primary afferent fibers project to the dorsal column nuclei in the postsynaptic dorsal column pathway. The projection of cells in the cervical spinal cord of monkeys to the cuneate nucleus has been reported to avoid pars rotunda of that nucleus, the part that contains the somatotopic representation of the ipsilateral hand. We used the sensitive anterograde tracer Phaseolus vularis leucoagglutinin to reexamine this projection. We made multiple iontophoretic injections into the cervical enlargements of three monkeys (two Macaca fascicularis and one Macaca mulatta). Control injections were made in the contralateral dorsal columns of one of these and in the dorsal roots of a fourth animal (M. fascicularis) to test for transport by fibers of passage. After 28–39 days, the animals were deeply anesthetized and perfused, and the tissue was processed for immunohistochemical detection of the label. In all cases (excluding control injections), labeled fibers and varicosities were distributed widely in the ipsilateral cuneate and external cuneate nuclei, including pars rotunda. The dorsal column nuclei ipsilateral to control injections contained no label or only very few poorly labeled fibers, indicating that labeling through fibers of passage did not contribute importantly to the results. This study indicates that the postsynaptic projection to the cuneate nucleus is widespread and includes pars rotunda. Such projections may contribute to transmission of information originating in nociceptors through the dorsal column‐medial lemniscal system to the ventrobasal thalamus. © Wiley‐Liss, Inc.
Maturation of neuron types in nucleus of solitary tract associated with functional convergence during development of taste circuits
Authors: Mistretta Charlotte M. , Labyak Susan E. 
Published: January 2005

AbstractLate fetal through postnatal development in sheep is a period of increasing convergence of afferent taste fibers onto second‐order neurons in the nucleus of the solitary tract (NST). To learn whether neuron morphology alters in concert with convergence and neurophysiological development in NST, three‐dimensional neuron reconstructions were made of cells in a functionally defined region of gustatory NST from Golgi preparations of the brainstem. Elongate, multipolar, and ovoid neurons were studied in fetuses from 85 days of gestation through the perinatal period (term = 147 days of gestation), to postnatal stages. Somal size and form, and dendritic complexity and extent, increased markedly from 85 to about 110 days of gestation in both of the proposed NST projection neurons, elongate and multipolar. From 130 days of gestation to postnatal ages, growth of dendrites of elongate neurons plateaued or declined, whereas dendrites of multipolar neurons apparently continued to increase in size and extent. In addition, spine density decreased on elongate neurons but remained stable on multipolar neurons. Morphological variables of ovoid cells, proposed interneurons in NST, did not alter over this later period. The data suggest that multipolar, not elongate or ovoid, neurons are logical candidates to receive the increasing afferent fiber input onto NST cells during late gestation. Also, neural activity from taste afferent fibers is more likely to have a role in altering NST neuron morphology at later, rather than earlier, developmental periods. © 1994 Wiley‐Liss, Inc.
Neuroactive substances in the developing dorsomedial telencephalon of the pigeon (Columba livia): Differential distribution and time course of maturation
Authors: Erichsen Jonathan T. , Ciocchetti Andrea , Fontanesi Gigliola , Bagnoli Paola 
Published: January 2005

AbstractThe avian hippocampal formation has previously been shown to contain many of the same neurotransmitters and related enzymes that are found in mammals. In order to determine whether the relatively delayed development of the mammalian hippocampus is typical of other vertebrates, we investigated the maturation of a variety of heuroactive substances in the hippocampal formation of the homing pigeon. The distribution of two transmitter‐related enzymes, choline acetyltransferase (ChAT) and tyrosine hydroxylase (TH), the neurotransmitter GABA, and four neuropeptides (substance P, enkephalin, neuropeptide Y, and somatostatin) was studied by immniunohistochemistry in the developing hippocampal complex. The pattern and/or the time course of changes in the distribution of immunoreactivity varied among the different neuroactive substances examined. Immunoreactivity to ChAT and TH was found exclusively in fibers and terminal‐like processes, whereas GABA and peptide immunoreactivity was seen in cells and neuropil. Quantitative differences in the density, number, and size of stained cells were assessed by a computer‐assisted image analyzer. For the majority of the substances, developmental patterns in the distribution of immunoreactivity differ between the hippocampus proper and the area parahippocampalis, the two major areas that together make up the avian hippocampal complex. The adult pattern of immunoreactivity was generally attained by 3 weeks after hatching. For many of the neuroactive substances found in cell bodies, there was a gradual decrease in the density of immunoreactive cells with a concomitant increase in the density of immunoreactive neuropil. The actual number of stained cells usually increased to a peak at 9 days posthatching and then declined until 3 weeks posthatching, when the adult value was reached. These results are discussed in relation to the advantages that the pigeon hippocampal complex may provide in the study of developmental processes. Parallels with the distribution of the same neuroactive substances in the mammalian hippocampus are used to suggest possible functional similarities between the avian and mammalian hippocampal regions. © 1994 Wiley‐Liss, Inc.
Neuropeptide‐immunoreactive neurons projecting to the paraventricular hypothalamic nucleus in the rat
Authors: Moga Margaret M. , Saper Clifford B. 
Published: January 2005

AbstractThe paraventricular nucleus of the hypothalamus (PVH) is innervated by a variety of types of neuropeptide‐immunoreactive fibers. The cells of origin for many of these inputs are not known. In the present study, the combined retrograde fluorescence–immunofluorescence method was used to determine the cells of origin for neurotensin‐, corticotropin‐releasing factor‐, brain natriuretic peptide‐, somatostatin‐, and met‐enkephalin‐like immunoreactive (‐ir) fibers in the PVH. After injections of the fluorescent tracer Fluorogold into the PVH, the pattern of retrograde labeling was as previously reported (Sawchenko and Swanson, 1983, J. Comp. Neurol. 218:121–144; McKellar and Loewy, 1981, Brain Res. 217:351–357). The distribution of each type of double‐labeled neuron was unique. Retrogradely labeled enkephalin‐ir neurons were concentrated in two locations: the ventral part of the lateral septal nucleus and the lateral anterior nucleus within the AHA. A small cluster of corticotropin‐releasing factor‐ir neurons in the ventral lateral subnucleus of the bed nucleus of the stria terminalis were retrogradely labeled. Notable concentrations of somatostatin‐ir double‐labeled neurons were found in the ventral part of the lateral hypothalamic area and the medial part of the arcudte hypothalamic nucleus. Neurotensin‐ir double‐labeled neurons were most numerous in the anteroventral periventricular nucleus and in the retrochiasmatic area. Many brain natiuretic peptide‐ir neurons in the tuberomammillary nucleus of the hypothalamus and in the pedunculopontine and laterodorsal tegmental nuclei were retrogradely labeled. The specificity of these chemically defined projections helps lay the groundwork for examining the functional organization of PVH afferents. © 1994 Wiley‐Liss, Inc.
Growth of central nervous system auditory and visual nuclei in the postnatal gerbil (Meriones unguiculatus)
Authors: Rübsamen R. , Gutowski M. , Langkau J. , Dörrscheidt G. J. 
Published: January 2005

AbstractThe objective of the present study was, by using the Mongolian gerbil (Meriones unguiculatus) as an animal model, to provide data on the growth dynamics of central auditory and visual nuclei and to relate the growth of these structures to the growth of the entire brain. So far, no such systematic study has been performed in any mammalian species. The knowledge of the rates of development of central nervous sensory structures might be useful for understanding the contribution of the central nervous system to maturation of sensory processing.Increases in volumes of nuclei and changes in their shape were analyzed for animals at the day of birth (P0); at postnatal days P7, P15, P22, P28; and in the third month (P90). The auditory nuclei investigated were the cochlear nucleus, the superior olivary complex, the nuclei of the lateral lemniscus, the inferior colliculus, and the medial geniculate body. From the visual system, the superior colliculus and the lateral geniculate body were studied.At P15 (shortly after the onset of central auditory responsiveness), the volumes of all auditory nuclei examined reached only 60–70% of their adult sizes; i.e., they showed considerable growth afterwards. At the same time (shortly before the animals open their eyes), the visual nuclei had almost reached their adult sizes (superior colliculus, 91%; lateral geniculate nucleus, 97%).These data demonstrate that different sensory nuclei contribute in highly different fashions to brain growth. There are system‐specific differences in growth dynamics between central auditory and visual nuclei. However, the absolute growth of nuclei in both sensory systems relates to the brain regions. The data do not support the idea of a peripheral‐to‐central gradient in the growth of central auditory nuclei. © 1994 Wiley‐Liss, Inc.
Brainstem network controlling descending drive to phrenic motoneurons in rat
Authors: Dobbins Elizabeth G. , Feldman Jack L. 
Published: January 2005

AbstractContraction of the diaphragm is controlled by phrenic motoneurons that receive input from sources that are not fully established. Bulbospinal (second‐order) neurons projecting to phrenic motoneurons and propriobulbar (third‐order) neurons projecting to these bulbospinal neurons were investigated in rat by transsynaptic transport of the neuroinvasive pseudorabies virus. Bulbospinal neurons were located predominantly in the medullary lateral tegmental field in two functionally described regions, the ventral respiratory group and Bötzinger complex. An intervening region, the pre‐Bötzinger complex, contained essentially no phrenic premotoneu rons. Bulbospinal neurons were also located in ventral, interstitial, and ventrolateral subnuclei of the solitary tract, and gigantocellular, Kölliker‐Fuse, parabrachial, and medullary raphe nuclei. A monosynaptic pathway to phrenic motoneurons from the nucleus of the solitary tract was confirmed; monosynaptic pathways from upper cervical, spinal cord, spinal trigeminal nucleus, medial and lateral vestibular nuclei, and medial pontine tegmentum were not verified. Locations of third‐order neurons were consistent with described projections to the ventral respiratory group, from contralateral ventral respiratory group, Bötzinger complex, A5 noradrenergic cell group, and the following nuclei: solitary, raphe, Kölliker‐Fuse, parabrachial, retrotrapezoid, and paragigantocellular. Novel findings included a projection from locus coeruleus to respiratory premotoneurons and the lack of previously described pathways from area postrema and spinal trigeminal nucleus. These second‐ and third‐order neurons form the output network for diaphragm motor control which includes numerous behaviors (e. g., respiration, phonation, defecation). Of the premotoneurons, the rostral ventral respiratory group is the primary population controlling phrenic motoneurons. © 1994 Wiley‐Liss, Inc.
Distribution of histamine‐, 5‐hydroxytryptamine‐, and tyrosine hydroxylase‐immunoreactive neurons and nerve fibers in developing rat brain
Authors: Vanhala Anu , Yamatodani Atsushi , Panula Pertti 
Published: January 2005

AbstractAlthough the general patterns of the developing histaminergic system in the rat brain are known, no comparative studies between the development of the brain histaminergic system and the development of other neuroactive substances have yet been published. Interestingly, separate immunohistochemical studies on the development of the 5‐HT system and on the catecholaminergic system in the rat imply common features in the different aminergic systems. Therefore, the spatial distribution of histamine‐immunoreactive (HA‐ir) neurons and nerve fibers was compared to the distribution of 5‐hydroxytryptamine (5‐HT)‐, and tyrosine hydroxylase‐immunoreactive (TH‐ir) ones in the developing rat brain between embryonic days 12, (E12) and 20 (E20) by using a double‐immunostaining method. The high‐pressure liquid chromatography (HPLC) fluorometric method was used for determination of histamine concentration in different brain regions during the same period of development and synthetic oligonucleotide probes complementary to the rat histidine decarboxylase (HDC) to determine the origin of HA in the brain during the development with in situ hybridization. The immunohistoch6mical results revealed co‐localization of HA and 5‐HT within a subgroup of cells in the developing raphe nuclei between E14 and E18. From E18 onwards HA immunoreactivity started to gradually disappear from the rhombencephalon, and was totally abolished by E20, while 5‐HT‐ir cells continued to establish their adult positions. No significant colocalization of RA and TH immunoreactivities was detected. The biochemical results were in agreement with the immunohistochemical ones and confirmed that histamine detected in the early developing brain is authentic. A positive in situ hybridization signal for HDC was detected in a small area in the ventrolateral pons in the same areas as HA‐ and HDC‐ir cell bodies at E16, suggesting that at least some HA may be synthesized locally. These results confirm that HA is one of the first neurotransmitters to appear in the developing brain. In addition, the transient co‐localization of HA and 5‐HT immunoreactivities and the transient HDC expression at E16 within the developing pontine raphe nuclei may imply an interesting and a more general role for HA in modification of brain development. © 1994 Wiley‐Liss, Inc.
Serotonin‐immunoreactive neurons and endogenous serotonin in the opisthosomal ventral nerve cord of the horseshoe crab, Limulus polyphemus
Authors: Washington Benny , Higgins Denise E. , McAdory Brenda , Newkirk Robert F. 
Published: January 2005

AbstractIt has been suggested that serotonin serves as a neurotransmitter in the horseshoe crab, Limulus polyphemus. While some studies of identified groups of central neurons have been conducted, little is known concerning the neuronal organization in Limulus central ganglia. This study was undertaken to determine the localization of serotoninergic neurons in the opisthosomal ventral nerve cord of Limulus and to construct a basis for further comparative biochemical and pharmacological studies of the specific function of these neurons. Endogenous serotonin was, detected in the ventral nerve cord (chain of abdominal ganglia) by high performance liquid chromatography and electrochemical detection (HPLC‐EC). Endogenous serotonin was quantified in the 9th through 13th ganglia, anterior (hemal) nerves, posterior (branchial) nerves, and connectives. The serotonin content in the abdominal ganglia was significantly reduced when the ganglia were incubated for 24 hours in Leibovitz's (L‐15) medium containing reserpine or 5, 7‐dihydroxytryptamine (5, 7‐DHT), neurotoxins that block the uptake of serotonin into storage vesicles. The distribution of serotonin‐immunoreactive neurons in the ventral nerve cord was determined by indirect immunocytochemistry. Treatment of the chain of ganglia with an anti‐serotonin antiserum followed by treatment with a fluorescent‐labeled antiserum raised against the primary antibody demonstrated specific staining in each, ganglion, the ganglionic roots, and connectives. Clusters of serotonin immunoreactive neurons were observed anteriolaterally and posteriorly in each ganglion. Processes from dense fiber bundles extended from these clusters of neurons to the central region of each ganglion. These results demonstrate that serotonin‐immunoreactive neurons are present in the opisthosomal ventral nerve cord of the horseshoe crab and that serotonin may function as a neurotransmitter. © 1994 Wiley‐Liss, Inc.