bluuebunny/crossref_metadata_2025_split huggingface dataset:
Squint‐induced Modification of Visual Receptive Field in the Lateral Suprasylvian Cortex of the Cat: Binocul Interaction, Vertical Effect and Anomalous Correspondence
Authors: Sireteanu Ruxandra , Best Johannes 
Published: April 2006

AbstractIn this study, we investigated the receptive field properties of single cells in the lateral suprasylvian area of strabismic cats. More than three times as many cells could be driven by the non‐operated than by the operated eye. Many more cells could be activated by the contralateral than by the ipsilateral eye. In both area 17 and the lateral suprasylvian area, more cells preferred horizontal rather than vertical or oblique orientations (‘vertical effect’). In addition, a small percentage of cells in the lateral suprasylvian area showed an adaptive shift of spatial coordinates; this shift could provide the neural basis of anomalous retinal correspondence.
Baclofen and the Release of Neuropeptides in the Cat Spinal Cord
Authors: Morton C. R. , Hutchison W. D. , Lacey G. 
Published: April 2006

AbstractThe antibody microprobe technique was used to study the effect of baclofen on the release of immunoreactive substance P and immunoreactive calcitonin gene‐related peptide within the lower lumbar spinal cord of pentobarbitone‐anaesthetized spinalized cats. Both peptides were released in the region of the substantia gelatinosa during ipsilateral noxious cutaneous stimulation or high‐intensity electrical stimulation of a hind limb nerve. Intravenous administration of baclofen suppressed the excitation of lumbar dorsal horn neurons, but did not produce detectable alterations of the evoked release of immunoreactive substance P or immunoreactive calcitonin gene‐related peptide in the superficial grey matter dorsal to these neurons. The results suggest that the antinociceptive action of baclofen does not involve a reduction of the intraspinal release of substance P or calcitonin gene‐related peptide from the central terminals of nociceptive sensory fibres.
Immunoreactivity for Taurine Characterizes Subsets of Glia, GABAergic and non‐GABAergic Neurons in the Neo‐ and Archicortex of the Rat, Cat and Rhesus Monkey: Comparison with Immunoreactivity for Homocysteic Acid
Authors: Kritzer M. F. , Cowey A. , Ottersen O. P. , Streit P. , Somogyi P. 
Published: April 2006

AbstractThe cerebral cortex is an area rich in taurine (2‐aminoethanesulphonic acid), but only limited information exists regarding its cellular distribution. We therefore examined taurine‐like immunoreactivity in the cerebral cortex of the rat, cat and macaque monkey using antiserum directed against glutaraldehyde‐conjugated taurine. Immunostaining was assessed at the light and electron microscopic level, and patterns obtained in light microscopic studies were compared to those produced with antiserum to γ‐aminobutyric acid (GABA) and homocysteic acid (HCA). In all three species, strong taurine‐like immunoreactive perivascular endothelial cells, pericytes and oligodendrocytes were found. These cells were located throughout the neuropil, which itself showed a low level of immunoreactivity. In rats and cats, a small number of weakly taurine‐enriched neurons were observed, particularly in superficial layers. In all cortical areas of the macaque, however, glial staining was matched by strong, selective staining of subpopulations of cortical neurons which were distributed in a bilaminar pattern involving layers II/III and VI. In addition, in primary visual cortex, area 17, immunopositive neurons were also present in sublayer IVCβ, while in the hippocampus strongly taurine‐positive neurons were most conspicuous in the granule cell layer of the dentate gyrus. In all regions, strongly taurine‐positive neurons constituted only a subpopulation of the neurons occupying a given layer. Examination of adjacent sections for GABA immunoreactivity showed that the most strongly taurine‐positive neurons in layers II/III were immunoreactive for GABA. The cells located in layers IVCβ and VI, and the granule cells of the dentate gyrus, however, were GABA‐negative. The morphological features of these latter groups suggested that the antiserum to taurine identifies subsets of spiny stellate, small pyramidal and dentate granule cells. None of these neurons showed immunoreactivity with antiserum to HCA in the primate; HCA‐positive glia were found along the pial and white matter boundaries of the cortex, and showed no overlap with strongly taurine‐positive glial elements. Although a transmitter role for taurine may be unlikely, particularly in view of its enrichment in subpopulations of both inhibitory and excitatory cells, the capacity of taurine to influence membrane‐associated functions in excitable tissues, and its selective distribution demonstrated here, provides the potential for a contribution to communication between cortical cells.
Differential Localization of Two Alternatively Spliced GABAA Receptor γ2‐Subunit mRNAs in the Chick Brain
Authors: Glencorse Thora A. , Bateson Alan N. , Darlison Mark G. 
Published: April 2006

AbstractTwo variants of the GABAA receptor γ2 subunit are known to exist, which differ by the presence (γ2L) or absence (γ2S) of eight amino acids in the presumed intracellular loop between the third and fourth membrane‐spanning domains. These variants have been shown to be generated by alternative splicing of the γ2‐subunit primary gene transcript in mouse (Kofuji et at., J. Neurochem., 56, 713–715, 1991), and in bovine and human (Whiting et al., Proc. Natl. Acad. Sci. USA, 87, 9966–9970, 1990) brain. We describe here the cloning, from chick (Gallus domesticus) brain, of cDNAs that encode the γ2L and γ2S subunits, and report on the regional and cellular localization of the corresponding mRNAs as revealed by in situ hybridization histochemistry with transcript‐specific oligonucleotide probes. While the two transcripts are found to be colocalized throughout the chick neuroaxis, certain nuclei (for example, the nucleus isthmi, pars magnocellularis, the nucleus isthmi, pars parvocellularis, the nucleus solitarius and the paleostriatum primitivum) are found to contain predominantly either the γ2S‐ or the γ2L‐subunit mRNA. We conclude that receptors that contain either the γ2S or the γ2L subunit occur, and that these probably have functionally different roles in the modulation of neurotransmission in the central nervous system. In addition, our data indicate that certain cells may produce both transcripts. Consequently, these will have either a single receptor subtype that contains both a γ2S and a γ2L subunit, or two receptor subtypes, one of which contains a γ2S subunit and the other a γ2L subunit.
Distribution of Cutaneous Nociceptive and Tactile Climbing Fibre Input to Sagittal Zones in Cat Cerebellar Anterior Lobe
Authors: Garwicz M. , Ekerot C.‐F. , Schouenborg J. 
Published: April 2006

AbstractClimbing fibres projecting to the cerebellar C3 zone (and the related C1 and Y zones) receive spatially well organized tactile and nociceptive inputs from the skin. In the present study, cutaneous tactile and nociceptive input to climbing fibres projecting to the X, B, C2 and D1 zones in lobule V were investigated in pentobarbitone‐anaesthetized cats. From the present results and previous studies, it is concluded that the X, C1, CX, C3 and Y zones receive cutaneous nociceptive climbing fibre input. By contrast, climbing fibres to the B, C2 and D1 zones lack cutaneous nociceptive input. Tactile input was found in all zones. The spatial organization of receptive fields of climbing fibres projecting to the X and D1 zones was similar to that in the C3 zone. They were located on the ipsilateral forelimb, mainly its lateral and distal parts, and their proximal borders were located close to joints. In the B zone, more than half of the receptive fields of climbing fibres were confined to the ipsilateral hind‐ or forelimb. However, frequently more than one limb and parts of the trunk were included. In the C2 zone, the majority of climbing fibres had distal ipsi‐ or bilateral receptive fields on the forelimbs, often also including the head/face. Some of the bilateral forelimb receptive fields additionally included the hindlimbs ipsi‐ or bilaterally. The results indicate that each zone has a characteristic set of climbing fibre receptive fields, which is probably related to its efferent control functions.
Somatosensory Trigeminal Projections to the Inferior Olive, Cerebellum and other Precerebellar Nuclei in Rabbits
Authors: Van Ham Jacqueline J. , Yeo Christopher H. 
Published: April 2006

AbstractWe have analysed the pathways through which somatosensory information from the face reaches the inferior olive and the cerebellum in rabbits. We used wheatgerm agglutinin ‐ horseradish peroxidase (WGA‐HRP) to trace projections from all parts of the somatosensory trigeminal system to the olive, cerebellar cortex, the cerebellar deep nuclei and the pontine nuclei. Projections to the cerebellar cortex and inferior olive were verified using retrograde transport of WGA‐HRP. Two regions of the inferior olive–the medial dorsal accessory olive and the ventral leaf of the principal olive–receive inputs from pars interpolaris (Vi) and rostral pars caudalis (Vc) of the spinal trigeminal nucleus and from the principal trigeminal nucleus (Vp). Another area in the caudal medial accessory olive receives inputs from rostral Vo (pars oralis of the spinal trigeminal nucleus), caudal Vi and Vc. There are trigemino‐olivo‐cortical inputs to lobule HVI via all these olivary areas and to the paramedian lobe via the principal olive only. Cerebellar cortex–lobules HVI, crus I and II, paramedian lobe and IX–receives direct mossy fibre inputs from Vp, Vo and rostral Vi. The pontine nuclei receive an input only from rostral Vi. We saw no trigeminal projections to other precerebellar nuclei or to the deep cerebellar nuclei. The concentration of face somatosensory cortical inputs, via several pathways, upon lobule HVI may underlie its important role in the regulation of learned and unlearned eyeblinks.
High Degree of NCAM Diversity Generated by Alternative RNA Splicing in Brain and Muscle
Authors: Barthels Dagmar , Vopper Gaby , Boned Annie , Cremer Harold , Wille Wolfgang 
Published: April 2006

AbstractThe neural cell adhesion molecules (NCAMs) are cell surface glycoproteins involved in vertebrate cell contact formation. Several NCAM mRNA types are generated from a single primary transcript by alternative splicing and differential polyadenylation. In this presentation we analyse sequence heterogeneities within NCAM transcripts detected in the junctions of exons 7/8, 12/13 and 13/14. The highest degree of evolutionary conservation is observed in the 30‐nucleotide insertion (π) between exons 7 and 8, coding for an identical peptide sequence in the mouse, rat and chicken. The most complex splicing pattern is found between exons 12 and 13, called splice site a. Three alternative exons of 15, 48 and 42 nucleotides can be inserted in various combinations, which may also contain the additional trinucleotide AAG. In mouse muscle cell lines, differential ‘extra exon’ and AAG usage in splice site α creates up to 16 NCAM diversity forms, some (if not all) of which are also expressed in mouse brain. Additional microdiversity is generated by the insertion of an alternative AAG trinucleotide in exon junction 13/14. If all combinations of splicing patterns identified so far were to occur and to be translated, there could be up to 192 different NCAM proteins.
Oscillatory Neuronal Responses in the Visual Cortex of the Awake Macaque Monkey
Authors: Kreiter A. K. , Singer W. 
Published: April 2006

AbstractAn important step in early visual processing is the segmentation of scenes. Features constituting individual objects have to be grouped together and segregated from those of other figures or the background. It has been proposed that this grouping could be achieved by synchronizing the fine temporal structure of responses from neurons excited by an individual figure. In the cat visual cortex evidence has been obtained that responses of feature‐selective neurons have a distinctive oscillatory structure and can synchronize both within and across cortical areas, the synchronization depending on stimulus configuration. Here we investigate the generality of oscillatory responses and their synchronization and specifically whether these phenomena occur in extrastriate areas of the visual cortex of the awake behaving primate. We find in the caudal superior temporal sulcus of the macaque monkey (Macaca fascicularis) that adjacent neurons can synchronize their responses, in which case their discharges exhibit an oscillatory temporal structure. During such periods of local synchrony spatially separated cell groups can also synchronize their responses if activated with a single stimulus. These findings resemble those described previously for the cat visual cortex, except that in the awake monkey the oscillatory episodes tend to be of shorter duration and exhibit more variability of oscillation frequency.
Striatal c‐fos Induction by Cocaine or Apomorphine Occurs Preferentially in Output Neurons Projecting to the Substantia Nigra in the Rat
Authors: Cenci M. Angela , Campbell Kenneth , Wictorin Klas , Björklund Anders 
Published: April 2006

AbstractFluorogold or rhodamine‐labelled latex beads were injected in the substantia nigra (SN) or the globus pallidus (GP) in order retrogradely to label striatal output neurons that project to the two target structures. Ten days later, striatal c‐fos was induced by systemic administration of cocaine (five normal rats; 25 mg/kg cocaine i.p. 2 h before killing) or apomorphine (five unilaterally dopamine‐denervated rats; 0.25 mg/kg apomorphine s. c. 2 h before killing), and detection of the Fos protein in the striatum was achieved by immunofluorescence. Sections through the caudate‐putamen that displayed good labelling from both SN and GP were selected for a quantitative analysis: the number of retrogradely labelled cells that exhibited Fos immunoreactivity, as well as the total number of retrogradely labelled cells located within a grid (0.16 mm2 in size) were counted manually at 25 x magnification. Cocaine induced a proportionally higher c‐fos expression in striate‐nigral compared to striate‐pallidal neurons, whereas apomorphine activated Fos almost exclusively in striate‐nigral neurons. The present findings are consistent with the idea that striatal c‐fos induction by dopaminergic agents is primarily mediated by an interaction with D1 ‐receptors, which are thought to be selectively localized on neurons projecting to SN.
Amnesia for Complex Naturalistic Scenes and for Objects Following Fornix Transection in the Rhesus Monkey
Authors: Gaffan D. 
Published: April 2006

AbstractRhesus monkeys (Macaca mulatta) were trained to discriminate among many complex naturalistic scenes. The scenes were still frames from a cinema film. They were presented as the discriminative stimuli in a concurrent discrimination learning task in which each discriminative stimulus was presented on one trial each day. Learning of this task was severely impaired by fornix transection. The same animals were also deficient in a similar concurrent discrimination learning task, with each discriminative stimulus presented on one trial each day, but with objects, not complex scenes, as the stimulus material. The impairment in object discrimination learning in the present experiment is attributable to an interaction of object discrimination learning with scene discrimination learning, and can be understood as an effect of interference in long‐term memory. In contrast to these impairments in long‐term memory, a test of within‐session learning of complex scenes, in which the average interval between successive presentations of the same stimulus was <3 min, was performed without significant impairment by the fornix‐transected animals. These results show that long‐term memory for complex naturalistic scenes reveals analogues in the monkey of human episodic memory and its impairment in amnesia.
Modulation by NMDA Receptor Antagonists of Glycine Receptor Isoform Expression in Cultured Spinal Cord Neurons
Authors: Hoch W. , Betz H. , Schramm M. , Wolters I. , Becker C. M. 
Published: April 2006

AbstractTwo developmentally regulated isoforms of the inhibitory glycine receptor harbouring different α subunit variants, GlyRN (neonatal) and GlyRA (adult), have previously been identified in rodent spinal cord. Primary cultures of embyronic spinal neurons, however, express predominantly GlyRN. Here, N‐methyl‐d‐aspartate (NMDA) receptor antagonists were found to significantly increase glycine receptor levels in mouse spinal cord cultures. In the presence of 2‐amino‐5‐phosphonovalerate or MK‐801 (dizocilpine), both GlyRN and GlyRA contents were elevated, as revealed by isoform‐selective immunoassays and amplification of corresponding α subunit transcripts by the polymerase chain reaction. This effect of NMDA receptor antagonists was restricted to a ‘sensitive’ period within the second week after plating. Apparently, NMDA receptor‐mediated glutamate neurotoxicity prevented GlyRA accumulation under standard culture conditions. Our data indicate that neuronal maturation in cell culture depends on conditions which minimize cell death resulting from glutamate release into the culture medium.
Regulation of Neurotrophin mRNA Expression in the Rat Brain by Glucocorticoids
Authors: Barbany Gisela , Persson Håkan 
Published: April 2006

AbstractNorthern blot analysis was used to examine the effects of glucocorticoids on neurotrophin mRNA expression in the rat cerebral cortex and hippocampus. The results show that 3 days after adrenalectomy the mRNA levels for nerve growth factor (NGF), brain‐derived neurotrophic factor (BDNF) and neurotrophin‐3 (NT‐3) decreased significantly in both these regions. In adrenalectomized animals given dexamethasone replacement the mRNA levels for the three neurotrophins were restored to control levels. The effect of a single dose of dexamethasone (5 mg/kg) administered i p. to intact animals on the expression of neurotrophins was also examined. NGF and NT‐3 mRNAs showed a 2.5‐fold and a 1.4‐fold increase, respectively, during the first 4 h after the injection. The increase was followed by a decrease, with levels ‐50% of control 24 and 48 h after the injection. In contrast, the level of BDNF mRNA did not change during the first 10 h after the injection, but decreased to 70% of control 48 h after the injection. These data indicate that glucocorticoids regulate neurotrophin mRNA expression both in the cortex and in the hippocampus, and suggest further that the known effects of glucocorticoids on neuronal survival in the brain could be due to changes in the levels of neurotrophins in the brain.
Role of Dopaminergic D2 Receptors in the Regulation of Glutamic Acid Decarboxylase Messenger RNA in the Striatum of the Rat
Authors: Caboche Jocelyne , Vernier Philippe , Rogard Monique , Julien Jean‐François , Mallet Jacques , Besson Marie‐Jo 
Published: April 2006

AbstractLevels of messenger RNA (mRNA) encoding glutamic acid decarboxylase (GAD) and preproenkephalin (PPE) were measured by Northern blot and in situ hybridization analyses in the striatum of the rat, after chronic injections of two neuroleptics, sulpiride and haloperidol. The Northern blot analysis showed that the chronic injection of sulpiride at high doses (80 mg/kg, twice a day, 14 days) increased striatal GAD and PPE mRNA levels by 120% and 78% respectively, when compared to vehicle‐injected rats. Haloperidol injections at relatively low doses (1 mg/kg, once a day, 14 days) produced parallel increases in GAD (40%) and PPE (52%) mRNA levels. After in situ hybridization densitometric measurements were performed on autoradiograms from rats treated with sulpiride, haloperidol or vehicle. The distribution of GAD and PPE mRNA signals in control rats was homogeneous along the rostrocaudal extension of the striatum. A similar increase was found along this axis after sulpiride (20%) and haloperidol (30%) treatments. The cellular observation of hybridization signals showed that grain density for GAD mRNA was increased in a majority of striatal cells after both treatments. By contrast, the PPE mRNA hybridization signal only increased in a subpopulation of neurons. The effects of such treatments were also analysed by measuring GAD activity in the striatum and in its output structures, the globus pallidus and the substantia nigra. After the administration of sulpiride, GAD activity was not modified in the striatum but increased in the globus pallidus (by 17%). After haloperidol treatment, GAD activity was increased in the globus pallidus (20%) and the substantia nigra (17%). It is concluded that the interruption of dopaminergic transmission, more precisely the D2 receptor blockade, promotes in striatopallidal neurons an increase in GAD mRNA accompanied by an increase in GAD activity and PPE mRNA. A possible regulation of GAD mRNA and GAD activity in striatonigral neurons is also discussed.
Expression of Ciliary Neurotrophic Factor and the Neurotrophins – Nerve Growth Factor, Brain‐Derived Neurotrophic Factor and Neurotrophin 3—in Cultured Rat Hippocampal Astrocytes
Authors: Rudge John S. , Alderson Ralph F. , Pasnikowski Elizabeth , McClain Joyce , Ip Nancy Y. , Lindsay Ronald M. 
Published: April 2006

AbstractCultured astrocytes are known to possess a range of neurotrophic activities in culture. In order to examine which factors may be responsible for these activities, we have examined the expression of the genes for four known neurotrophic factors – ciliary neurotrophic factor (CNTF), nerve growth factor (NGF), brain‐derived neurotrophic factor (BDNF) and neurotrophin 3 (NT3) – in purified astrocyte cultures derived from neonatal rat hippocampus. Hippocampal astrocytes were found to express mRNA for three neurotrophic factors – CNTF, NGF and NT3 – at significantly higher levels than other cultured cell types or cell lines examined. BDNF messenger RNA (mRNA), however, was undetectable in these astrocytes. The levels of CNTF, NGF and NT3 mRNA in astrocytes were largely unaffected by their degree of confluency, while serum removal caused only a transient decrease in mRNA levels, which returned to basal levels within 48 h. Astrocyte‐derived CNTF was found to comigrate with recombinant rat CNTF at 23 kD on a Western blot. Immunocytochemical analysis revealed strong CNTF immunoreactivity in the cytoplasm of astrocytes, weak staining in the nucleus, but no CNTF at the cell surface. NGF and NT3 were undetectable immunocytochemically. CNTF‐like activity, as assessed by bioassay on ciliary ganglion neurons, was found in the extract of cultured astrocytes but not in conditioned medium, whereas astrocyte‐conditioned medium supported survival of dorsal root ganglion neurons but not ciliary or nodose ganglion neurons. This conditioned medium activity was neutralized with antibodies to NGF. Astrocyte extract also supported survival of dorsal root ganglion and nodose ganglion neurons, but these activities were not blocked by anti‐NGF. Part, but not all, of the activity in astrocyte extracts which sustained nodose ganglion neurons could be attributed to CNTF.