bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dopaminergic neurons in rat ventral midbrain express brain‐derived neurotrophic factor and neurotrophin‐3 mRNAs
Authors: Seroogy Kim B. , Lundgren Kerstin H. , Tran Tien M. D. , Guthrie Kathleen M. , Isackson Paul J. , Gall Christine M. 
Published: January 2005

AbstractStudies of the trophic activities of brain‐derived neurotrophic factor and neurotrophin‐3 indicate that both molecules support the survival of a number of different embryonic cell types in culture. We have shown that mRNAs for brain‐derived neurotrophic factor and neurotrophin‐3 are localized to specific ventral mesencephalic regions containing dopaminergic cell bodies, including the substantia nigra and ventral tegmental area. In the present study, in situ hybridization with 35S‐labeled cRNA probes for the neurotrophin mRNAs was combined with neurotoxin lesions or with immunocytochemistry for the catecholamine‐synthesizing enzyme tyrosine hydroxylase to determine whether the dopaminergic neurons, themselves, synthesize the neurotrophins in adult rat midbrain. Following unilateral destruction of the midbrain dopamine cells with 6‐hydroxydopamine, a substantial, but incomplete, depletion of brain‐derived neurotrophic factor and neurotrophin‐3 mRNA‐containing cells was observed in the ipsilateral substantia nigra pars compacta and ventral tegmental area. In other rats, combined in situ hybridization and tyrosine hydroxylase immunocytochemistry demonstrated that the vast majority of the neurotrophin mRNA‐containing neurons in the substantia nigra and ventral tegmental area were tyrosine hydroxylase immunoreactive. Of the total population of tyrosine hydroxylase‐positive cells, double‐labeled neurons constituted 25–50% in the ventral tegmental area and 10–30% in the substantia nigra pars compacta, with the proportion being greater in medial pars compacta. In addition, tyrosine hydroxylase/neurotrophin mRNA coexistence was observed in neurons in other mesencephalic regions including the retrorubral field, interfascicular nucleus, rostral and central linear nuclei, dorsal raphe nucleus, and supramammillary region. The present results demonstrate brain‐derived neurotrophic factor and neurotrophin‐3 expression by adult midbrain dopamine neurons and support the suggestion that these neurotrophins influence dopamine neurons via autocrine or paracrine mechanisms. These data raise the additional possibility that inappropriate expression of the neurotrophins by dopaminergic neurons could contribute to the neuropathology of disease states such as Parkinson's disease and schizophrenia. © 1994 Wiley‐Liss, Inc.
The lacteridian reticular thalamic nucleus projects topographically upon the dorsal thalamus: Experimental study in Gallotia galloti
Authors: Díaz Carmen , Yanes Carmen , Trujillo Carmen‐María , Puelles Luis 
Published: January 2005

AbstractThe projection pattern of the ventral thalamic reticular nucleus onto the dorsal thalamus was studied in the lizard Gallotia gallotiusing in vitro horseradish peroxidase and fluorescent carbocyanine labelling techniques. Localized label deposits at three dorsoventrally spaced sites in the dorsal thalamus elicited retrograde transport into separate, though partly overlapping, medial, dorsolateral and ventrolateral sectors within an extended cytoarchitectonic complex which may be globally identifiable as the reticular nucleus. Neurons found in the dorsolateral and ventrolateral sectors mainly corresponded to the cell group named nucleus ventromedialis (or nucleus of the dorsal supraoptic decussation) in the literature, whereas neurons labelled in the medial sector corresponded to the so‐called dorsal hypothalamic nucleus. Sparser cells appear labelled in the superficially placed nucleus suprapeduncularis. Thalamotelencephalic fibers arising from the injected dorsal thalamic nuclei also project on the corresponding retrogradely labeled sectors within the reticular nucleus.These findings reveal a rough topographic organization in the connections of the extended reticular nucleus complex with the whole dorsal thalamus. This supports the hypothesis of hodological homology between this ventral thalamic formation in Gallotiaand the mammalian thalamic reticular nucleus. © 1994 Wiley‐Liss, Inc.
Presence of growth inhibitors in fish optic nerve myelin: Postinjury changes
Authors: Sivron T. , Schwab M. E. , Schwartz M. 
Published: January 2005

AbstractThis study shows that the fish optic nerve, which is able to regenerate after injury, contains myelin‐associated growth inhibitors similar to the growth inhibitors present in mammalian central nervous system (CNS) myelin. The ability of nerves to regenerate was previously correlated with the ability of sections from these nerves to support neuronal attachment to and axonal growth in vitro. Thus neuroblastoma cells or embryonic neurons became attached to and grew axons on sections of rat sciatic nerve or fish optic nerve, which are spontaneously regenerating systems, but not on sections of rat optic nerve, a nongenerating system. Failure of the latter to support axonal growth has been attributed, at least in part, to growth inhibitors. Recently it was shown that adult neurons, which differ in their growth requirement from embryonic neurons, are unable to extend neurites on sections of normal sciatic nerve but are able to extend neurites on sections of sciatic nerve that was injured prior to its excision. We found a similar in the fish optic nerve, i.e. that the nerve is normally not permissive to growth of adult retinal axons but becomes growth permissive after injury. The nonpermissiveness of the normal fish optic nerve was found to correlate with the presence of myelin‐associated growth‐inhibitory molecules. This inhibitory activity of fish myelin was neutralized by IN‐1 antibodies, known to neutralize rat myelin growth inhibitors apparently similar or even identical to those of rat, but possibly present in lower amounts than in the rat. Results are discussed with respect to the possibility that fish optic nerve, like the rat sciatic regeneration of adult neurons. Such changes might include elimination or neutralization of growth inhibitors. © 1994 Wiley‐Liss, Inc.
Ionotropic glutamate‐receptor gene expression in hypothalamus: Localization of AMPA, kainate, and NMDA receptor RNA with in situ hybridization
Authors: Van Den Pol Anthony N. , Hermans‐Borgmeyer Irm , Hofer Magdalena , Ghosh Prabhat , Heinemann Stephen 
Published: January 2005

AbstractIn situ hybridization and Northern blots were used to study the ionotropic subtypes of the glutamate receptor in the rat hypothalamus. Widespread expression of AMPA, kainate, and NMDA receptor RNA was found in the hypothalamus with the transcripts the same size and number as found in other regions of the brain. Most of the glutamate‐receptor subunits studied were expressed in greater amounts in hippocampus than in hypothalamus; GluR5, on the other hand, showed a greater expression in hypothalamus than in hippocampus. On the basis of Northern blot analysis, all regions of the brain examined, including hypothalamus, cerebral cortex, cerebellum, olfactory bulb, and hippocampus, expressed all eight of the subunits studied. Each subunit showed different relative expressions in the different regions.In the hypothalamus, GluR1 and GluR2 were among the most widely expressed of the non‐NMDA ionotropic receptors. Other AMPA‐preferring receptors, GluR3 and ‐R4, were also found, but to a lesser extent. Scattered cells expressed the kainate‐preferring receptors GluR5, ‐R6, and ‐R7. The NMDA receptor NMDAR1 was detected throughout the hypothalamus. In many regions of the hypothalamus, only scattered cells showed detectable expression of the glutamate‐receptor mRNA as detected by autoradiographic silver grains over neurons; unlabeled cells were mixed among labeled cells. Every region of the hypothalamus had several different glutamate receptors. The expression of many different types of ionotropic glutamate receptors throughout the hypothalamus suggests that multiple modes of ion channel regulation by glutamate probably operate here and provides further support for the importance of the excitatory transmitter glutamate in hypothalamic regulation. © 1994 Wiley‐Liss, Inc.
Distinct distributions of five NMDA receptor channel subunit mRNAs in the brainstem
Authors: Watanabe Masahiko , Mishina Masayoshi , Inoue Yoshiro 
Published: January 2005

AbstractThe distribution of five NMDA receptor channel subunit mRNAs in the mouse brainstem at postnatal day 21 was semiquantitatively examined by in situ hybridization with subunitspecific oligonucleotide probes. The ∈1 subunit mRNA was observed in various brainstem nuclei. On the other hand, the ∈2 and ∈3 subunit mRNAs were restricted to particular nuclei, and the ∈4 subunit mRNA was detected in several nuclei at very low levels. The dorsal cochlear nucleus exhibited differential expressions of the ∈ subunit mRNAs in distinct neuron types: the ∈2 subunit mRNAin the pyramidal cells, the ∈3 subunit mRNA in the granule cells, and the ∈1 subunit mRNA in other neurons. In the vestibular nuclei, the medial nucleus expressed the ∈1, ∈3, and ∈4 subunit mRNAs, whereas the lateral and superior nuclei expressed the ∈1 subunit mRNA. Such region‐specific expressions were also discerned in the central gray, the superior and inferior colliculi, the medical accessory oculomotor nucleus, the locus ceruleus, the parabrachial nucleus, nucleus of the solitary tract, the caudal subnucleus of the trigeminal spinal tract nucleus, and the inferior olive. In contrast to the differential distributions of the four ∈ subunit mRNAs, intense signals for the ζ1 subunit mRNA were distributed throughout the brainstem. These findings suggest that anatomical organization of the ∈ subunits is heterogeneous in various regions of the brainstem, which would give rise to functional diversity of the NMDA receptor channel in these regions. © 1994 Wiey‐Liss, Inc.
Regulation of retinal ganglion cell axon arbor size by target availability: Mechanisms of compression and expansion of the retinotectal projection
Authors: Xiong Meijuan , Pallas Sarah L. , Lim Steve , Finlay Barbara L. 
Published: January 2005

AbstractThe ability of pre‐ and postsynaptic populations to achieve the proper convergence ratios during development is especially critical in topographically mapped systems such as the retinotectal system. The ratio of retinal ganglion cells to their target cells in the optic tectum can be altered experimentally either by early partial tectal ablation, which results in an orderly compression of near‐normal numbers of retinal projections into a smaller tectal area, or by early monocular enucleation, which results in the expansion of a reduced number of axons in a near‐normal tectal volume. Our previous studies showed that changes in cell death and synaptic density consequent to these manipulations can account for only a minor component of this compensation for the population mismatch.In this study, we examine other mechanisms of population matching in the hamster retinotectal system. We used an in vitro horseradish peroxidase labeling method to trace individual retinal ganglion cell axons in superior colliculi partially ablated on the day of birth, as well as in colliculi contralateral to a monocular enucleation. We found that individual axon arbors within the partially lesioned tectum occupy a smaller area, with fewer branches and fewer terminal boutons, but preserve a normal bouton denstiy. In contrst, ipsilaterally projecting axon arbors in monoculary enucleated animals occupy a greater area than in the normal condition, with a much larger arbor length and greater number of boutons and branches compared with normal ipsilaterally projecting cells. Alteration of axonal arborization of retinalganglion cells is the main factor responsible for matching the retinal and tectal cell populations within the tectum. This process conserves normal electrophysiological function over a wide range of convergence ratios and may occur through strict selectivity of tectal cells for their normal number of inputs. © 1994 Wiley‐Liss, Inc.
Information processing within the motor cortex. II. Intracortical connections between neurons receiving somatosensory cortical input and motor output neurons of the cortex
Authors: Kaneko Takeshi , Caria Marcello A. , Asanuma Hiroshi 
Published: January 2005

AbstractConnections between motor cortical neurons receiving somatosensory inputs from area 2 and large pyramidal cells in layer V were examined in the cat via intracellular injection of biocytin and immunohistochemistry of nonphosphorylated neurofilament proteins (npNFP). Biocytin was injected into pyramidal cells in layers II/III of the motor cortex that responded monosynaptically and polysynaptically to microstimulation of the somatosensory cortex and subsequently stained black by the avidin‐biotinylated preoxidase complex method with diaminobenzidine (DAB) and nickel. By using a monoclonal antibody SMI‐32 and a modified peroxidase‐antiperoxidase method with Tris‐aminophenylmethane (TAPM) and p‐cresol as a chromogen, pyramidal cells in layers III and V of the motor cortex were stained red for npNFP. In particular, all the large pyramidal cells in layer V, Betz cells, displayed intense npNFP immunoreactivity not only in the perikarya but also in the dendrites.Double staining with DAB/nickel and TAPM/p‐cresol showed that biocytin‐filled axon varicosities of the pyramidal cells, which were thought to receive monosynaptic inputs from area 2, made contacts with npNFP‐positive dendrites in layers I‐III around the biocytininjected cell and in layers V‐VI beneath the cell. The present results suggest that the corticocortical input from area 2 to pyramidal cells in layers II/III of the motor cortex is transferred to layer V pyramidal cells, including Betz cells, as well as to neighboring layer II/ III pyramidal cells. Since tetanic stimulation of the somatosensory cortex reportedly produces long‐term potentiation in layer II/III cells of the motor cortex, it seems reasonable to assume that a given area of the somatosensory cortex can produce a long‐lasting change in the activity of a given group of output cells in the motor cortex. © 1994 Wiley‐Liss, Inc.
Distinct spatiotemporal distributions of the N‐Methyl‐D‐aspartate receptor channel subunit mRNAs in the mouse cervical cord
Authors: Watanabe Masahiko , Mishina Masayoshi , Inoue Yoshiro 
Published: January 2005

AbstractThe distribution of five N‐methyl‐D‐aspartate (NMDA) receptor channel subunit mRNAs in the mouse spinal cord from embryonic day 13 (E13) through postnatal day 56 (P56) was semiquantitatively examined at the cervical level via in situ hybridization with subunit‐specific oligonucleotide probes. Signals for the ξ1 subunit mRNA were restricted to the most ventral portion of the spinal cord during embryonic stages. They extended to all laminae of the spinal cord except for the lamina 2 (substantia gelatinosa) during postnatal development. A wide expression of the ϵ2 subunit mRNA was found in the spinal gray matter from E13 through neonatal stages, but the signals became restricted to the lamina 2 by P21. No significant signals for the ϵ3 subunit mRNA were detected in the spinal cord at any developmental stages. The ϵ4 subunit mRNA was distributed widely in the spinal cord during embryonic and early postnatal periods but decreased nearly to background levels by P21. In contrast to the differential distribution of the ϵ subunit mRNAs, the ξ1 subunit mRNA was found ubiquitously at each developmental stage examined. These findings suggest that the molecular organization of the ϵ subunits may be difference between the dorsal horn and the remaining regions in the mature spinal cord, which provides a molecular basis for functional heterogeneity of the NMDA receptor channel. Moreover, this spatial heterogeneity might be generated through drastic alterations in the subunit composition of the channel complex during spinal cord development. © 1994 Wiley‐Liss, Inc.
Ontogeny of catecholamine systems in the central nervous system of anuran amphibians: An immunohistochemical study with antibodies against tyrosine hydroxylase and dopamine
Authors: González Agustín , Marín Oscar , Tuinhof Rienk , Smeets Wilhelmus J. A. J. 
Published: January 2005

AbstractTo get more insight into developmental aspects of catecholamine systems in vertebrates, in particular anuran amphibians, these systems were studied immunohistochemically in embryos and larvae of Xenopus laevis and Rana ridibunda. Antisera against tyrosine hydroxylase (TH) and dopamine (DA) revealed that catecholamine systems are already present at early embryonic stages. The first dopamine group to be detected was found ventral to the central canal of the spinal cord of Xenopus, soon followed by DA cell groups in the posterior tubercle, the hypothalamic periventricular organ, the accompanying cell group of the periventricular organ, and the suprachiasmatic nucleus. Although weakly TH‐immunoreactive cells were found in the olfactory bulb at about the same embryonic stages, DA immunoreactivity was not detected until premetamorphic stage 49. Dopamine cell groups in the caudal brainstem, midbrain, and pretectum appeared at late premetamorphic and prometamorphic stages, whereas the preoptic group was first observed at the metamorphic climax stage. Rana showed an almost similar timetable of development of catecholamine cell groups, except for the caudal brainstem group which was already present at the end of the embryonic period. When compared with previous studies by means of formaldehyde‐induced fluorescence technique, it becomes clear that TH/DA immunohistochemistry enables an earlier detection of catecholamine cell groups and fiber systems in anuran, amphibians. The present study also revealed that the DA‐immunoreactive cells of the hypothalamic periventricular, organ never stained with the TH antiserum during development, thus supporting their putatively DA accumulating nature. Another notable result is the site of origin and rather late appearance of the midbrain dopaminergic cell group. It is, suggested that the latter cell group only partly corresponds to the ventral tegmental area and substantia nigra of amniotes. © 1994 Wiley‐Liss, Inc.
Astrocyte proliferation in the chick auditory brainstem following cochlea removal
Authors: Lurie Diana I. , Rubel Edwin W. 
Published: January 2005

AbstractAstrocytes in the central nervous system (CNS) respond to injury and disease by proliferating and extending processes. The intermediate filament protein of astrocytes, glial fibrillary acidic protein (GFAP) also increases in astrocytes. These cells are called “reactive astrocytes” and are thought to play a role in CNS repair. We have previously demonstrated rapid increases (< 6 hours) in GFAP‐immunoreactive and silver‐impregnated glial processes in the chick cochlear nucleus, nucleus magnocellularis (NM), following cochlea removal or activity blockade of the eighth nerve. It was not known whether these changes were the result of glial proliferation, glial hypertrophy, or both. The present study examined the time course of astrocyte proliferation in NM following cochlea removal.Postnatal chicks received unilateral cochlea removal and survived for 6, 12, 18, 24, 36, 48, and 72 hours. Bromodeoxyuridine was used to label proliferating cells. The volume and number of labeled cells in NM was calculated for both the experimental and control sides of the brains for experimental animals was well as for unoperated control animals.A subset of astrocytes continuously divide in the normal posthatch chick brainstem. The percentage of labeled nuclei increases within NM 36 hours following cochlea removal and is robust by 48 hours. This increase is due to astrocyte proliferation within, rather than migration to, NM. These resulis indicate that rapid increases in GFAP following reduced activity are independent of cell proliferation. The time course of astrocyte proliferation suggests that cellular degeneration within the nucleus may play a role in upregulating astrocyte proliferation. © 1994 Wiley‐Liss, Inc.
Comparative anatomy of serotonin‐like immunoreactive neurons in isopods: Putative homologues in several species
Authors: Thompson Kevin S. J. , Zeidler Martin P. , Bacon Jonathan P. 
Published: January 2005

AbstractIt is now commonly accepted that the arthropod nervous system has evolved only once, and so homologies between crustacean and insect nervous systems can be meaningfully sought. To do this, we have examined the distribution of serotonin (5‐hydroxytryptamine)‐like immunoreactive neurons in the central nervous system (CNS) of four common British isopods. Two species of terrestrial woodlouse, Oniscus asellus and Armadillidium vulgare, the littoral sea slater, Ligia oceanica, and the aquatic water hoglouse, Asellus meridianus, all possess approximately 40 pairs of serotonin‐like immunoreactive neurons, distributed throughout the CNS in a very similar pattern. Interspecific homology is clearly suggested. Serotonin‐like immunoreactive neurons in the first (T1) and fourth (T4) thoracic ganglia are particularly prominent in each of the four species studied. Whole‐mount immunohistochemistry shows that the pair of T1 neurons have large dorsolateral cell bodies and prominent neurites that project medially and then anteriorly, whereas the pair of T4 neurons have ventrolateral cell bodies and neurites that bifurcate to form a thin axon projecting anteriorly to terminate in T3 and a thick medial axon that projects posteriorly into the abdominal neuromeres of the terminal ganglion. Intracellular cobalt staining of these neurons reveals more of their arborizations: The T1 neurons send three processes anteriorly, which arborize in the brain and exit from the CNS via peripheral nerves, whereas the T4 neurons contribute considerably to the extensive pattern of serotonin‐like immunoreactive fibres in T3–T6 ganglia.The overall pattern of serotonin‐like immunoreactiveneurons in the isopods is similar to that in decapod crustacea, and a number of putative homologies can be assigned. It is more difficult to homologize the isopod serotonin‐like immunoreactive neurons with those in the insect CNS, but some stained brain and thoracic neurons share common cell body positions and axon trajectories in isopods, decapods, and insects and may therefore be homologous. © 1994 Wiley‐Liss, Inc.