bluuebunny/crossref_metadata_2025_split huggingface dataset:
GABAA/benzodiazepine receptor α6 subunit mRNA in granule cells of the cerebellar cortex and cochlear nuclei: Expression in developing and mutant mice
Authors: Varecka Ludovit , Wu Chieh‐Hsi , Rotter Andrej , Frostholm Adrienne 
Published: January 2005

AbstractThe gamma aminobutyric acidA/benzodiazepine (GABAA/BZ) receptor is a multisubunit (α, β, γ, δ, and ρ) ligand‐gated chloride channel; there are several variants of the α, β, and γ subunits, each of which has been localized throughout the central nervous system. A large number of GABAA/BZ subunit variants are expressed within the cerebellar cortex. In previous studies from other laboratories, α6 subunit mRNA has been reported to be present exclusively in cerebellar granule cells. The developmental expression of α6 mRNA in cerebellar and cochlear granule cells is of interest because it has been suggested that each of these cell types is derived from a common precursor pool. The polymerase chain reaction was used to generate a cDNA fragment encoding a portion of the M3–M4 intracellular loop of the α6 subunit of the GABAA/BZ receptor. A [35S] riboprobe, transcribed from this cDNA fragment, was used to examine the expression of the α6 subunit mRNA by in situ hybridization in developing normal mice and in adult mutant mice with known deficits in synaptic circuitry. A strong hybridization signal was observed over the granule cell layers of both the cerebellum and cochlear nuclei in adult mice. The signal over the cochlear nuclei appeared after birth toward the end of postnatal week 1, coinciding with the appearance of labeling in the cerebellar cortex. The intensity of the hybridization signal in both regions increased rapidly until postnatal day 14, after which it increased more gradually, reaching adult levels during postnatal week 3. In the weaver mutant, α6 labeling was detected in surviving granule cells, but not in cerebellar regions devoid of granule cells. Significant levels of the α6 hybridization signal were also present in cerebellar granule cells of Purkinje cell degeneration, lurcher, and staggerer mutants, suggesting that aberrations in synaptic circuitry do not prevent α6 subunit gene expression.Our results demonstrate that α6 subunit mRNA is not limited to the cerebellum, but is expressed in other neurons which share a common cellular precursor pool. These data also suggest that these granule cell precursors may be intrinsically programmed to acquire a specific form of the GABAA/BZ receptor, irrespective of their final location and lack of connections with target neurons. © 1994 Wiley‐Liss, Inc.
Clusterin (SGP‐2): A multifunctional glycoprotein with regional expression in astrocytes and neurons of the adult rat brain
Authors: Pasinetti Giulio M. , Johnson Steven A. , Oda Tomiichiro , Rozovsky Irina , Finch Caleb E. 
Published: January 2005

AbstractClusterin (SGP‐2) is a newly described glycoprotein associated with several putative functions including responses to brain injury. This study reports the regional and cell type expression of clusterin mRNA and its encoded glycoprotein in the rat brain; a limited comparison was also done with the human brain. Using in situ hybridization combined with immunocytochemistry, we found that astrocytes and neurons may express clusterin mRNA in the normal adult brain. While astrocytes throughout the brain contained clusterin mRNA, there was regional selectivity for neuronal clusterin expression. In the striatum, clusterin mRNA was not detected in neurons. Only a subset of substantia nigra dopaminergic neurons or locus ceruleus noradrenergic neurons (tyrosine hydroxylase immunopositive) contained clusterin mRNA. However, neuronal clusterin mRNA was prevaìent in pontine nuclei and in the red nucleus of the midbrain tegmentum. Similarly, clusterin mRNA was prevalent in both rat and human hippocampal neuron‐specific enolase immunopositive pyramidal neurons, although rat CA1 neurons had less mRNA than CA2–CA3 neurons. Monotypic primary cell cultures from the neonatal rat showed clusterin mRNA in both neurons and astrocytes, but not in microglia.By immunocytochemistry, no clusterin immunopositive glia were observed in any region of the rat brain, confirming previous studies. However, clusterin immunopositive cells (putative neurons) were observed in the Purkinje cell layer of the cerebellum, medial and interposed cerebellar nuclei, trigeminal motor nucleus, and red nucleus. Finally, in vitro studies suggest that astrocytes, but not neurons, secrete clusterin, which is pertinent to clusterin immunodeposits found after experimental lesioning. © 1994 Wiley‐Liss, Inc.
Vestibulo‐oculomotor connections in an elasmobranch fish, the atlantic stingray, Dasyatis sabina
Authors: Puzdrowski R. L. , Leonard R. B. 
Published: January 2005

AbstractIn elasmobranch fishes, including the Atlantic stingray, the medial rectus muscle is innervated by the contralateral oculomotor nucleus. This is different from most vertebrates, in which the medial rectus is innervated by the ipsilateral oculomotor nucleus. This observation led to the prediction that the excitatory vestibulo‐extraocular motoneuron projections connecting each semicircular canal to the appropriate muscle should use a contralateral projection from the vestibular nuclei to the motoneurons. This hypothesis was examined in the Atlantic stingray by injecting horseradish peroxidase unilaterally into the oculomotor nucleus. It was found that vestibulo‐oculomotor projections arise from the ipsilateral anterior octaval nucleus and the contralateral descending octaval nucleus. The same pattern was observed when the trochlear nucleus was involved in the injection. There were no cells labeled in the region of the abducens nucleus, and no candidate for a nucleus prepositus hypoglossus was identified. The presence of compensatory eye movements, the directional sensitivity of the semicircular canals, the location of the motoneurons innervating each eye muscle, and our results indicate that the excitatory input to the extraocular motoneurons is derived from the contralateral descending octaval nucleus, and the inhibitory input is derived from the ipsilateral anterior octaval nucleus. The absence of both abducens internuclear interneurons and a nucleus prepositus hypoglossus suggests that eye movements, particularly those in the horizontal plane, are controlled differently in elasmobranchs than in other vertebrates examined to date. © 1994 Wiley‐Liss, Inc.
Compartmentation of glutamate and glutamine in the lateral cervical nucleus: Further evidence for glutamate as a spinocervical tract neurotransmitter
Authors: Kechagias Stergios , Broman Jonas 
Published: January 2005

AbstractPrevious observations indicate that spinocervical tract terminals contain relatively high levels of glutamate. To examine whether these high glutamate levels are likely to represent a neurotransmitter pool or an elevated metabolic pool, the distributions of glutamate‐ and glutamine‐like immunoreactivities were examined in adjacent immunogold‐labeled sections of the lateral cervical nucleus. Spinocervical tract terminals were identified by anterograde transport of horseradish peroxidase and wheat germ agglutinin‐horseradish peroxidase conjugate from the spinal cord.Spinocervical tract terminals were found to contain significantly higher levels of glutamate‐like immunoreactivity than other examined tissue compartments (large neuronal cell bodies, terminals with pleomorphic vesicles, astrocytes, and average tissue level). In contrast, the highest levels of glutamine‐like immunoreactivity were detected in astrocytes. The different analyzed tissue elements formed three groups with respect to glutamate: glutamine ratios: one high ratio group including spinocervical tract terminals, a second group with intermediate ratios consisting of neuronal cell bodies and terminals containing pleomorphic synaptic vesicles, and a third low ratio group including astrocytes.Our findings indicate the presence of a compartmentation of glutamate and glutamine in the lateral cervical nucleus, similar to that postulated in biochemical studies of the central nervous system. The results also show that spinocervical tract terminals have high glutamate: glutamine ratios, similar to those previously observed in putative glutamatergic terminals in the cerebellar cortex. Thus, spinocervical tract terminals display biochemical characteristics that would be expected of glutamatergic terminals and the present findings therefore provide further evidence for glutamate as a spinocervical tract neurotransmitter. © Wiley‐Liss, Inc.
Three‐dimensional organization of endoplasmic reticulum in the ventral photoreceptors of Limulus
Authors: Feng Jane J. , Carson John H. , Morgan Frank , Walz Bernd , Fein Alan 
Published: January 2005

AbstractLiving Limulus ventral photoreceptor cells were injected with long chain lipophilic carbocyanine fluorescent dyes to label the endoplasmic reticulum (ER). The purpose of this study was to examine the continuity, dynamic changes, and structure of the ER in the living cell, using laser scanning confocal microscopy and three‐dimensional image reconstruction.In this highly polarized neuron, three lines of evidence indicate that the ER is a continuous network extending throughout both lobes of the cell. First, injection of DiO or DiI results in the labeling of ER throughout both lobes of the cell. Second, three‐dimensional image reconstruction of the optical sections reveals a dispersed membrane meshwork which may be the structure that serves to interconnet the ER in the two lobes. Third, in cells fixed before dye injection, the pattern of labelling was similar to that in living cells, indicating that vesicle transport was not responsible for the spread of dye throughout the cell.The overall organization of the ER in the photoreceptor cell is relatively stable; however, the fine structure changes over time. This dynamic process appears to represent continual reorganization of the intracellular membranes in the cell.Three morphological types of ER were observed. The ER of the light‐sensitive lobe, identified by coinjection of rhodamine‐phalloidin to label the microvillar actin, is characterized by a concentration of stratiform membranes interconnected by thin tubular cross‐bridges. The perinuclear ER is characterized by a tangle of convoluted tubules sometimes terminating in bulbous structures. Finally, there is a fine tubular reticulum dispersed throughout the cell.
Embryonic sensory development: Local expression of neurotrophin‐3 and target expression of nerve growth factor
Authors: Elkabes Stella , Dreyfus Cheryl F. , Schaar Dale G. , Black Ira B. 
Published: January 2005

AbstractDevelopment and maintenance of peripheral sensory and sympathetic neurons are regulated by target‐derived neurotrophins, including nerve growth factor (NGF). To determine whether trophins are potentially critical prior to and during target innervation, for neuronal survival or axon guidance, in situ hybridization was performed in the rat embryo. We examined the expression of genes encoding NGF, neurotrophin‐3 (NT‐3), and their putative high‐affinity receptors, trk A and trk C, respectively. Trks A and C were detected in dorsal root sensory ganglia (DRG) on embryonic day 12.5 (E12.5), implying early responsiveness to NGF and NT‐3. NGF mRNA was expressed in the central spinal cord target and by the peripheral somite, at this early time, which thereby may function as a transient “guidepost” target for sensory fibers. Somitic expression was transient and was undetectable by E17.5. NT‐3 was expressed in the DRG itself from E13.5 to 17.5, suggesting local transient actions on sensory neurons. NT‐3 was also expressed in the ventral spinal cord at low levels on E13.5. We examined the trigeminal ganglion to determine whether cranial sensory neurons are similarly regulated. Trk A was detected in the trigeminal ganglion, while NGF was expressed in the central myelencephalon target, paralleling observations in the DRG and spinal cord. However, NT‐3 and trk C were undetectable, in contrast to DRG, suggesting that the environment or different neural crest lineages govern expression of different trophins and trks. Apparently, multiple trophins regulate sensory neuron development through local as well as transient target mechanisms prior to innervation of definitive targets.
Excitatory amino acid antagonists protect cochlear auditory neurons from excitotoxicity
Authors: Puel J.‐L. , Pujol R. , Tribillac F. , Ladrech S. , Eybalin M. 
Published: January 2005

AbstractSince ischemic damage in the brain is linked to glutamate excitotoxicity, the effects of an acute exposure to glutamate, α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole proprionic acid (AMPA) or N‐‐methyl‐D aspartate (NMDA) on the radial dendrites were compared with these occurring after a severe cochlear ischemia. Glutamate and AMPA, but not NMDA, produced a drastic swelling restricted to the radial dendrites below the inner hair cells (IHCs). At a concentration of 20 μM AMPA, a full electrophysiological recovery could be observed in some cochleas after washing the drug out. A prior perfusion of 6‐7‐dinitroquinoxaline‐2,3‐dione (DNQX, 50 μM) prevented the 25 μM AMPA‐induced dendritic swelling. No protective effect of D‐2‐amino‐5‐phosphonopentanoate (D‐AP5) could be observed. In the same way, ischemia (5‐40 minutes) resulted in a clear swelling of the radial dendrites. While D‐AP5 had no protective effects, 50 μM DNQX protected most of the radial dendrites from the ischemia‐induced swelling, excepting those contacting the modiolar side of the IHCs. Finally, 50 μM DNQX + 50 μM D‐AP5 resulted in a nearly complete protection of all the radial dendrites. Altogether, these results suggest that the acute swelling of radial dendrites primarily occurs via AMPA/kainate receptors. However, in radial dendrites contacting the inner hair cells on their modiolar side, NMDA receptors may be also involved.
NADPH diaphorase (nitric oxide synthase)‐containing nerves in the enteropancreatic innervation: Sources, co‐stored neuropeptides, and pancreatic function
Authors: Kirchgessner A. L. , Liu M.‐T. , Gershon M. D. 
Published: January 2005

AbstractPancreatic ganglia are innervated by neurons in the gut and are formed by precursor cells that migrate into the pancreas from the bowel. The innervation of the pancreas, therefore, may be considered an extension of the enteric nervous system. NADPH‐diaphorase is present in a subset of enteric neurons. We investigated the presence of NADPH‐diaphorase in the enteropancreatic innervation, the contribution of extrinsic nerves to the NADPH‐diaphorase‐containing fibers of the gut and pancreas, and the coincident expression of NADPH‐diaphorase in intrinsic neurons of these organs with neuropeptides. The possible role of nitric oxide in the neural regulation of pancreatic secretion was studied in isolated pancreatic lobules. Neuronal perikarya with NADPH‐diaphorase activity were found in both Dogiel type I and type II neurons of the myenteric plexus of the stomach and duodenum. All galanin (GAL)‐immunoreactive neurons and a small subset of vasoactive intestinal polypeptide (VIP)‐ and neuropeptide Y (NPY)‐immunoreactive neurons contained NADPH‐diaphorase activity. NADPH‐diaphorase activity was also found in a subset of VIP and NPY‐immunoreactive pancreatic neurons. Retrograde tracing with FluoroGold established that NADPH‐diaphorase‐containing neurons in the bowel project to the pancreas. NADPH‐diaphorase‐containing fibers were also found to be provided to both organs by neurons in dorsal root ganglia. Secretion of amylase was evoked by L‐arginine. This effect was prevented by NG‐nitro‐L‐arginine (L‐NNA), which also inhibited VIP‐stimulated secretion of amylase; however, L‐NNA had no effect on amylase secretion stimulated by carbachol. These results provide support for the hypo‐thesis that nitric oxide plays a role in the neural regulation of pancreatic secretion. © 1994 Wiley‐Liss, Inc.
Primary olfactory fibres project to the ventral telencephalon and preoptic region in trout (Salmo trutta): A developmental immunocytochemical study
Authors: Becerra Manuela , Manso Maria Jesus , Rodriguez‐Moldes Isabel , Anadón Ramon 
Published: January 2005

AbstractWe studied the development of the primary olfactory system of a teleost, the brown trout, with the aims of clarifying whether the caudal projection pertains to the olfactory or to the terminal nerve system, of identifying the brain regions receiving this projection, and of investigating its possible functional significance. As olfactory markers (OMs) we used two polyclonal antibodies (to substance P and to α‐melanocyte‐stimulating hormone) that were found to label the olfactory projection strongly after preadsortion of the antibody with the corresponding antigen (OMs), and as a terminal nerve marker we used an antiserum to FMRF‐amide peptide. OM labelling was observed in both perikarya and axons of olfactory neurons. In adults, olfactory neurons projected not only to olfactory glomeruli in the olfactory bulb but also, as has been reported previously, to more caudal targets in the forebrain through the medial olfactory tract. Our results show that these targets include the ventral and commissural nuclei of the area ventralis telencephali, the periventricular preoptic region, and the organum vasculosum laminae terminalis. Glomeruli were not observed before hatching, and the extrabulbar olfactory projections appear late in development. Extensive periventricular preoptic olfactory plexuses and olfactory innervation of the organum vasculosum laminae terminalis did not appear until adulthood. The cells of the ganglion nervus terminalis, which form ganglionic groups along the olfactory nerves, were not stained with these olfactory markers at any developmental stage studied, nor was the medial olfactory tract FMRF‐amide peptide immunoreactive. Our results thus confirm the existence of primary olfactory projections to extrabulbar targets in trout. The target regions identified in this study are implicated in sexual behaviour: We discuss the related possibility that, in teleosts, these extrabulbar olfactory projections (rather than projections of the terminal nerve, as is widely held) are the primary mediators of neuroendocrine response to pheromones. © 1994 Wiley‐Liss, Inc.
Expression of the gene for the neuronal intermediate filament protein α‐internexin coincides with the onset of neuronal differentiation in the developing rat nervous system
Authors: Fliegner Karsten H. , Kaplan Michael P. , Wood Teresa L. , Pintar John E. , Liem Ronald K. H. 
Published: January 2005

AbstractWhile neurofilaments have long been considered early markers of neuronal differentiation, they cannot be detected in most newly postmitotic neurons of the developing central nervous system (CNS). Here we show that these neurons already express the neuronal intermediate filament protein α‐internexin at high levels. α‐internexin is expressed by most, if not all, neurons as they begin differentiation and shows no overlap with vimentin, whose expression in the CNS is restricted to mitotic neuronal precursors. In the adult, α‐internexin is the only intermediate filament gene expressed by the cerebellar granule cells, the source of the thin‐caliber parallel fibers; conversely, neurofilament proteins are highly expressed in large neurons, which express α‐internexin at low levels. These data suggest that neuronal intermediate filaments may regulate axonal stability and/or diameter through changes not only in their number, but also in their subunit composition. © 1994 Wiley‐Liss, Inc.
Central complex of the primate thalamus: A quantitative analysis of neuronal morphology
Authors: Fénelon Gilles , Yelnik Jérǒme , François Chantal , Percheron Gérard 
Published: January 2005

AbstractNeuronal morphology was analyzed in the central complex (centre median‐parafascicular complex) of macaques and humans. Cell bodies were described from Nissl material. Golgi‐impregnated dendritic arborizations were reconstructed from serial sections and digitized in three dimensions by computer‐assisted microscopy. The central complex was subdivided into three parts on the basis of cytoarchitectonic and hodological criteria: pars parafascicularis (medial), pars media (intermediate), and pars paralateralis (lateral). The mean cross‐sectional areas of cell bodies were identical (181 μm2) in the three parts in macaques. In humans they were larger in the pars parafascicularis (304 μm2) than in the other parts (248 and 240 μm2).Small local circuit neurons were found throughout the complex. Large projection neurons differed statistically in the three parts. In macaques, pars parafascicularis neurons had few dendritic stems and tips (3‐11) and a short total dendritic length (2,000 μm). Pars paralateralis neurons had more ramified (5–60) and longer (5,800 μm) dendrites. They bore numerous axonlike processes. Pars media neurons had intermediate characteristics (5–19; 2,400 μm). In humans, pars parafascicular neurons had similar topological characteristics (3–12) but longer dendrites (3,000 μm) than in the monkey. Pars paralateralis neurons had more branched (6–71) and longer (9,000 μm) dendrites, with more numerous axonlike processes. Pars media neurons also had intermediate characteristics (4–25; 3,800 μm). The present study supports a tripartite subdivision of the primate central complex and demonstrates significant interspecies differences. © 1994 Wiley‐Liss, Inc.
Nitric oxide producing neurons in the monkey and human digestive system
Authors: De Giorgio Roberto , Parodi José E. , Brecha Nicholas C. , Brunicardi F. Charles , Becker James M. , Go Vay Liang W. , Sternini Catia 
Published: January 2005

AbstractNitric oxide has been proposed as an inhibitory transmitter molecule that plays a role in muscle relaxation and vasodilation in the gastrointestinal tract. The present study analyzes the distribution of nitric‐oxide‐producing neurons in the monkey and human digestive system by means of nicotinamide‐adenine‐dinucleotide‐phosphate‐diaphorase histochemistry. This histochemical method is reliable and convenient for the visualization of neuronal nitric‐oxide synthase, the enzyme responsible for nitric‐oxide generation. In the gastrointestinal tract, nitric‐oxide‐synthase‐related diaphorase activity was present in nerve fibers running through‐out the muscle layer (circular > longitudinal) and in numerous ganglion cells and processes in the myenteric plexus of monkeys and humans. Labelled ganglion cells and fibers also were observed in the submucous plexus, although they were much less numerous than those seen in the myenteric plexus. In the submucosa, a few positive fibers were seen around blood vessels. In the mucosa, stained fibers were sparse at the base of the villi and crypts, whereas they were quite abundant in the muscularis mucosae, especially in the small intestine and colon. In the gallbladder (human), labelling was found in ganglion cells and processes of the innermost and outermost ganglionated plexuses. Stained fibers also were distributed to the muscular layer and, less abundantly, to the mucosa and vasculature. Labelled fibers were more abundant in the sphincter of Oddi (human) than in the gallbladder. In the monkey and human pancreas, nicotinamide‐adenine‐dinucleotide‐diaphorase staining was seen mainly in ganglion cells and fibers of intrapancereatic ganglia, and in processes running among acini, around ducts and in the stroma. A moderate density of stained fibers also was distributed to the vasculature, whereas the islets showed few positive processes. Finally, double label experiments performed in the pancreas showed that the vast majority of neurons producing intric oxide are immunoreactive for vasoactive intestinal peptide.The present results demonstrate that in the digestive tract of primates nitric‐oxide neurons and processes are widespread. This supports the hypothesis that neural nitric oxide plays a broader role than smooth‐muscle relaxation and vasodilation in the periphery. It may be involved in neuronal communication within the enteric plexuses and may influence different digestive functions including endocrine and exocrine secretions. © 1994 Wiley‐Liss, Inc.