bluuebunny/crossref_metadata_2025_split huggingface dataset:
Postnatal maternal deprivation produces long‐lasting modifications of the stress response, feeding and stress‐related behaviour in the rat
Authors: Penke, Zsuzsa , Felszeghy, Klára , Fernette, Brigitte , Sage, Dominique , Nyakas Csaba , Burlet Arlette 
Published: March 2003

AbstractThe hypothalamo‐pituitary‐adrenal (HPA) axis plays a central role both in the regulation of the stress response, and in the control of feeding behaviour. Sensitivity of the HPA axis to respond to stress varies both during ontogeny and between individuals, and can be altered by neonatal events. The aim of our experiments was to determine whether early events that affect the HPA axis could also induce persistent modifications in food intake (quantitatively and qualitatively), as well as alterations of anxiety‐related behaviour. Twenty‐four‐hour maternal deprivation was introduced at two different periods of HPA maturation, on day 5 (DEP5) or day 14 (DEP14) after birth. Sequential measurements of plasma levels of adrenocorticotropin hormone (ACTH) and corticosterone showed that this deprivation altered the HPA axis of adults; the response to restraint stress was prolonged in DEP5 and a higher ACTH peak appeared in DEP14. The neonatal stress also produced long‐lasting modifications of rat behaviour, as DEP14 adults became more anxious. Standard food intake decreased in both groups of deprived rats. Diet preferences also changed, as carbohydrate intake decreased in DEP5 rats. Corticosteroid receptor binding did not vary in the hippocampus of the deprived rats. The modifications of the stress response and the behaviour parameters could be due to the alteration of corticosteroid receptors in the hypothalamic paraventricular nucleus and/or corticotropin‐releasing hormone or vasopressin function, but these parameters have yet to be determined. This early stress paradigm altering feeding behaviour could become an interesting model for research into human eating disorders.
Optical imaging of spreading depolarization waves triggered by spinal nerve stimulation in the chick embryo: possible mechanisms for large‐scale coactivation of the central nervous system
Authors: Mochida Hiraku , Sato Katsushige , Arai Yoshiyasu , Sasaki Shinichi , Kamino Kohtaro , Momose‐Sato Yoko 
Published: March 2003

AbstractUsing a multiple‐site optical recording technique with a voltage‐sensitive dye, we found that widely spreading depolarization waves were evoked by dorsal root stimulation in embryonic chick spinal cords. Spatiotemporal maps of the depolarization waves showed that the signals were mainly distributed in the ventral half of the slice, with the highest activity in the ventrolateral area. The propagation velocity of the waves was estimated to be in the order of mm/s. Depolarization waves were evoked in the ventral root‐cut preparation, but not in the dorsal root‐cut preparation, suggesting that the wave was triggered by synaptic inputs from the primary afferents, and that activation of the motoneurons was not essential for wave generation. In intact spinal cord–brain preparations, the depolarization wave propagated rostrally and caudally for a distance of several spinal segments in normal Ringer's solution. In a Mg2+‐free solution, the amplitude and extent of the signals were markedly enhanced, and the depolarization wave triggered in the cervical spinal cord propagated to the brainstem and the cerebellum. The depolarization wave demonstrated here had many similarities with the vagus nerve‐evoked depolarization wave reported previously. The results suggest that functional cell‐to‐cell communication systems mediated by the depolarization wave are widely generated in the embryonic central nervous system, and could play a role in large‐scale coactivation of the neurons in the spinal cord and brain.
Choroid plexus and ageing in rats: a morphometric and ultrastructural study
Authors: Serot Jean‐Marie , Foliguet Bernard , Béné Marie Christine , Faure Gilbert C. 
Published: March 2003

AbstractChoroid plexuses (CP) are intraventricular structures involved in the production of cerebrospinal fluid (CSF) and in the synthesis and transport of numerous CSF components. Age‐related modifications of the CP structure are still ill defined. We performed an ultrastructural and morphometric study of ageing CP in nine Sprague–Dawley rats 6, 18 and 30 months of age. Epithelial cells of CP villi were cubic in shape at 6 months, more dome‐like at 18 months, and significantly flattened at 30 months of age. Epithelial basement membranes were thin and regular at 6 months, significantly thicker at 18 months and thicker and irregular at 30 months. Intravillous stroma increased nonhomogeneously with age. The ageing of CP in rats is characterized morphologically by epithelial atrophy, irregular fibrosis of the stroma and a thickening of epithelial basement membranes. These modifications suggest an alteration of secretory and filtrating functions in ageing CP.
Brain correlates of fast and slow handwriting in humans: a PET–performance correlation analysis
Authors: Siebner Hartwig R. , Limmer Claus , Peinemann Alexander , Bartenstein Peter , Drzezga Alexander , Conrad Bastian 
Published: March 2003

AbstractThe present study examined the cerebral control of velocity during handwriting. We employed H215O positron emission tomography (PET) to measure the regional cerebral blood flow (rCBF) in 10 healthy subjects. Participants were required to write the German verb ‘bellen’ (‘to bark’) either at their normal speed (i.e. fast open‐loop handwriting) or to write at approximately half of their normal speed without visual feedback. The second task required a continuous modification of the motor output according to the kinaesthetic feedback from the hand (i.e. slow closed‐loop handwriting). Pencil movements were recorded during PET scanning and analysed off‐line using a stroke‐based analysing program. The mean number of inversions in velocity (NIV) per stroke was used to quantify the mode of motor control during each PET scan. A NIV of 1 indicates fast open‐loop processing, whereas an increase in NIV reflects a shift towards slow closed‐loop processing of handwriting. Foci in the left primary sensorimotor cortex, the right lateral premotor cortex, the left anterior parietal cortex, the left anterior putamen, the left rostral supplementary motor area and the right precuneus showed a graded increase in functional activation with the mean NIV per stroke, suggesting that this set of brain regions is particularly involved in the processing of slow closed‐loop writing movements. No area showed a negative relationship between rCBF and the mean NIV per stroke, suggesting that fast open‐loop handwriting is achieved by an optimized cooperation of the manual sensorimotor network rather than by a selective activation of a distinct network component.
Regeneration in avian hair cell epithelia: identification of intracellular signals required for S‐phase entry
Authors: Witte Mark C. , Montcouquiol Mireille , Corwin Jeffrey T. 
Published: March 2003

AbstractBalance epithelia in birds closely resemble their mammalian counterparts, but their cells turnover rapidly and they quickly regenerate hair cells, leading to functional recovery from damage that would be permanent for a mammal. We isolated and cultured sheets of the chicken's utricular epithelium in bromo‐deoxyuridine and specific inhibitors of different intracellular signalling pathways to identify signals that influence turnover and regeneration. Synthesis (S‐phase) entry was effectively blocked by inhibition of PI3‐K, TOR or MAPK, and significantly decreased by inhibitors of PKC. Comparisons indicate that activated PI3‐K and TOR are required for S‐phase entry in both avian and mammalian balance epithelia, but activation of the MAPK pathway appears to have a more significant role in avian utricles than in mammals. The dissimilarities in the requirements for these signalling pathways do not appear sufficient to explain the marked difference in regenerative capacity between the ears of birds and mammals.
Disrupting basolateral amygdala function impairs unconditioned freezing and avoidance in rats
Authors: Vazdarjanova Almira , Cahill Larry , McGaugh James L. 
Published: March 2003

AbstractLesions of the lateral/basolateral amygdala nuclei (BLC) disrupt freezing behaviour in response to explicit or contextual cues (conditioned stimuli – CS) paired previously with footshock (unconditioned stimulus). This deficit in expression of defensive behaviour in response to conditioned stimuli is often interpreted as inability of lesioned rats to learn CS–US associations. However, findings of several studies indicate that BLC‐lesioned rats can rapidly learn CS–US associations. Such findings suggest that lesioned rats can learn CS–US associations but are impaired in the expression of freezing behaviour. In the present study we report that both temporary inactivation (lidocaine) and permanent excitotoxic (NMDA) lesions of the BLC impair the unconditioned freezing and avoidance behaviours of rats in response to a novel fear‐eliciting stimulus, a ball of cat hair. These findings suggest that the BLC influences the expression of freezing and avoidance behaviours, and/or that it potentiates rats' experience of fear. Along with prior evidence of spared memory for aversive learning after BLC lesions, these findings suggest that disrupted freezing to conditioned cues in BLC‐lesioned rats does not necessarily reflect inability to form CS–US associations.
The effects of digital anaesthesia on predictive grip force adjustments during vertical movements of a grasped object
Authors: Nowak Dennis A. , Hermsdörfer Joachim , Glasauer Stefan , Philipp Jens , Meyer Ludger , Mai Norbert 
Published: March 2003

AbstractGrip force adjustments to fluctuations of inertial loads induced by vertical arm movements with a grasped object were analysed during normal and impaired finger sensibility. Normally grip force is modulated in a highly economical way in parallel with fluctuations of load force. Two subjects performed vertical up and down movements of a grasped object, both with normal finger sensibility and then cutaneously anaesthetized finger sensibility. Short breaks were taken in between single movements, during which the object was held stationary. After digital anaesthesia was applied to the grasping fingers, both subjects substantially increased the grip force. The grip force amplitude and timing still anticipated changes in load force, although the established grip force had already overcome movement‐induced load force peaks. This implies that the increase of grip force and consequently the elevated force ratio between maximum grip and maximum load force are not processed to alter the feedforward system of grip force control. Cutaneous afferent information from the grasping digits appears to be necessary for economic scaling of the grip force level, but it plays a subordinate role in the precise anticipatory temporal coupling of grip and load forces during voluntary object manipulation.
Chronic desipramine treatment selectively potentiates somatostatin‐induced dopamine release in the nucleus accumbens
Authors: Pallis Eleftherios , Thermos Kyriaki , Spyraki Christina 
Published: March 2003

AbstractDopamine and somatostatin have been implicated in the pathophysiology of depression. We have employed in vivo microdialysis to investigate the regulation of dopamine release by somatostatin in the nucleus accumbens and the striatum of awake, freely moving rats, and to ascertain how this regulation may be affected by desipramine treatment. Somatostatin‐14 (10−4 m) infusion induced an increase in the release of dopamine and a decrease in the release of its metabolites in both the nucleus accumbens (568% of basal) and the striatum (546% of basal). Chronic desipramine treatment resulted in an exaggerated somatostatin‐induced increase of dopamine levels, specifically in the nucleus accumbens (3542% compared with 564% of basal in the striatum), whereas acute desipramine treatment had no effect (582% of basal) compared with saline treated rats. Basal concentrations of dopamine and metabolites were not influenced by either chronic or acute treatment of desipramine in either brain area. These results demonstrate that somatostatin regulates dopamine release in the nucleus accumbens and the striatum. Chronic antidepressant treatment influences somatostatin's actions on dopamine function selectively in the nucleus accumbens.
β‐Bungarotoxin is a potent inducer of apoptosis in cultured rat neurons by receptor‐mediated internalization
Authors: Herkert Matthias , Shakhman Olena , Schweins Elisabeth , Becker Cord‐Michael 
Published: March 2003

AbstractThe neurotoxic phospholipase A2, β‐bungarotoxin (β‐BuTx), is a component of the snake venom from the Taiwanese banded krait Bungarus multicinctus. β‐BuTx affects presynaptic nerve terminal function of the neuromuscular junction and induces widespread neuronal cell death throughout the mammalian and avian CNS. To analyse the initial events of β‐BuTx‐mediated cell death, the toxin was applied to cultured rat hippocampal neurons where it induced neuronal cell death in a concentration‐dependent manner (EC50≈ 5 × 10−13 m) within 24 h. Fluorescence labelled β‐BuTx was completely incorporated by neurons within < 10 min. Binding and uptake of β‐BuTx, as well as induction of cell death, were efficiently antagonized by preincubation with dendrotoxin I, a blocker of voltage‐gated potassium channels devoid of phospholipase activity. Binding of β‐BuTx was selective for neurofilament‐positive cells. As evident from intense annexin‐V and TUNEL stainings, application of β‐BuTx induced apoptotic cell death exclusively in neurons, leaving astrocytes unaffected. No evidence was obtained for any contribution of either caspases or calpains to β‐BuTx‐induced apoptosis, consistent with the inability of the inhibitors Z‐Asp‐DCB and calpeptin, respectively, to protect neurons from β‐BuTx‐induced cell death. These observations indicate that induction of cell death by β‐BuTx comprises several successive phases: (i) binding to neuronal potassium channels is the initial event, followed by (ii) internalization and (iii) induction of apoptotic cell death via a caspase‐independent pathway.
Control elements between −9.5 and −3.0 kb in the human tissue‐type plasminogen activator gene promoter direct spatial and inducible expression to the murine brain
Authors: Yu Hong , Schleuning Wolf‐Dieter , Michl Marna , Liberatore Gabriel , Tan Seong‐Seng , Medcalf Robert L. 
Published: March 2003

AbstractTissue‐type plasminogen activator (t‐PA) participates in the control of synaptic plasticity and memory formation in the central nervous system (CNS). Transgenic mice harbouring either 9.5, 3.0 or 1.4 kb of the human t‐PA promoter fused to the LacZ reporter gene were used to assess t‐PA promoter‐directed expression in vivo. The 9.5 kb t‐PA promoter directed expression to the brain, most notably to the dentate gyrus, superior colliculus, hippocampus, thalamus and piriform cortex. Staining was also observed in the retrosplenial and somatosensory cortex. The 3.0 kb t‐PA promoter directed generalized and poorly defined expression to the cortex and hippocampus, while the 1.4 kb t‐PA promoter directed expression selectively to the medial habenula. Intravenous administration of lipopolysaccharide into mice habouring the 9.5 kb t‐PA promoter resulted in an increase in reporter gene activity in the lateral orbital cortex and thalamus. Results of in vitro transfection experiments of NT2 cells with a series of t‐PA promoter deletion constructs confirmed the presence of regulatory elements throughout the 9.5 kb promoter region. Finally, we describe a cis‐acting element related to the NFAT recognition site that provides a protein‐binding site and which may play a role in the selective expression of the 1.4 t‐PA promoter in the medial habenula. These results indicate that elements between −3.0 and −9.5 kb of the t‐PA promoter confer constitutive and inducible expression to specific regions of the CNS.
Pallidal activity is involved in visuomotor association learning in monkeys
Authors: Inase M. , Li B.‐M. , Takashima I. , Iijima T. 
Published: March 2003

AbstractIn order to examine whether the basal ganglia are involved in arbitrary visuomotor association, we recorded neuronal activity in the internal segment of the globus pallidus (GPi) of monkeys during a conditional visuomotor learning task. Two monkeys were presented a cueing visual stimulus, and following a delay period required to push, pull or turn a manipulator according to the cue. GPi neurons showed changes in activity during the delay period when the animals performed the task on the basis of a familiar stimulus–response association. Those changes in delay activity were enhanced as the monkeys were learning a new visuomotor association. The enhancement of the changes was selective to a following response. These results suggest that the basal ganglia are involved in arbitrary visuomotor association, especially during the learning of new associations.
Involvement of intrinsic cholinergic and GABAergic innervation in the effect of NMDA on striatal dopamine efflux and metabolism as assessed by microdialysis studies in freely moving rats
Authors: Whitehead K. J. , Rose S. , Jenner P. 
Published: March 2003

AbstractMicrodialysis perfusion was used to study the participation of striatal cholinergic and γ‐aminobutyric acid‐ergic (GABAergic) neurotransmission in basal and N‐methyl‐d‐aspartate (NMDA) receptor‐modulated dopamine release and metabolism in the striatum of the freely moving rat. Reverse dialysis of atropine (1–50 µm) induced a concentration‐related increase in dopamine efflux and decrease in 3,4‐dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) efflux. (+)‐Bicuculline (10–100 µm) similarly increased dopamine efflux, but was without consistent effect on metabolite efflux. Reverse dialysis of NMDA (1 mm) evoked an approximately twofold increase in dopamine efflux and decreased DOPAC and HVA efflux to 30–40% of basal levels. The effect of NMDA on dopamine efflux was completely abolished by coadministration of tetrodotoxin (TTX; 1 µm) or atropine (10 µm), and markedly potentiated (approximately fourfold) by coadministration of (+)‐bicuculline (50 µm). The NMDA‐induced decrease in dopamine metabolite efflux was inhibited by coadministration of TTX or (+)‐bicuculline, but was unaffected by atropine. Our data suggest that dopamine release in the striatum is subject to both cholinergic and GABAergic tonic inhibitory mechanisms mediated through muscarinic and GABAA receptors, respectively. Furthermore, NMDA‐stimulated dopamine release also involves obligatory cholinergic facilitation and an inhibitory GABAergic component mediated through these respective receptors.
Independent receptors for diadenosine pentaphosphate and ATP in rat midbrain single synaptic terminals
Authors: Díaz‐Hernández M. , Pintor J. , Castro E. , Miras‐Portugal M. T. 
Published: March 2003

AbstractDiadenosine pentaphosphate (Ap5A) and adenosine 5′‐triphosphate (ATP) stimulate a intrasynaptosomal calcium concentration [Ca2+]i increase via specific purinergic receptors in rat midbrain synaptosomes, although nothing is known about their distribution in presynaptic terminals. A microfluorimetric technique to measure [Ca2+]i increase using the dye FURA‐2AM, has permitted study of the presence of dinucleotide and P2X receptors in independent isolated synaptic terminals. Our results demonstrate the existence of three populations of synaptosomes: one with dinucleotide receptors (12%), another with P2X receptors (20%) and a third with both (14%). It has been possible to demonstrate that the activation of these receptors occurs only in the presence of extracellular Ca2+ and that it is also coupled with voltage‐dependent Ca2+ channels. Finally 54% of the synaptosomes that responded to K+ did not present any calcium increase mediated by the nucleotides used. In summary, ATP and dinucleotides exhibit specific ionotropic receptors that can coexist or not on the same synaptic terminal.
Scaffolding proteins organize multimolecular protein complexes for sensory signal transduction
Authors: Huber Armin 
Published: March 2003

AbstractScaffolding proteins composed of protein–protein interaction domains have emerged as organizers of multiprotein complexes in diverse cellular compartments, including neuronal synapses, cell–cell junctions of epithelial cells, and the stimulus perceiving structures of sensory neurons. This review focuses on the INAD‐assembled signalling complex of Drosophila photoreceptors, which organizes key components of the phototransduction cascade into a multiprotein signal transduction unit. The structure, the physiological consequences, and the assembly and targeting of the members of the INAD signalling complex will be described. In addition, the existence of signalling complexes in vertebrate photoreceptors, olfactory neurons and mechanosensitive hair cells will be discussed.
Dominance of the lurcher mutation in heteromeric kainate and AMPA receptor channels
Authors: Schwarz Martin K. , Pawlak Verena , Osten Pavel , Mack Volker , Seeburg Peter H. , Köhr Georg 
Published: March 2003

AbstractHomomeric glutamate receptor (GluR) channels become spontaneously active when the last alanine residue within the invariant SYTANLAAF‐motif in the third membrane segment is substituted by threonine. The same mutation in the orphan GluRδ2 channel is responsible for neurodegeneration in ‘Lurcher’ (Lc) mice. Since most native GluRs are composed of different subunits, we investigated the effect of an Lc‐mutated subunit in heteromeric kainate and AMPA receptors expressed in HEK293 cells. Kainate receptor KA2 subunits, either wild type or carrying the Lc mutation (KA2Lc), are retained inside the cell but are surface‐expressed when assembled with GluR6 sununits. Importantly, KA2Lc dominates the gating of KA2Lc/GluR6WT channels, as revealed by spontaneous activation and by slowed desensitization and deactivation kinetics of ligand‐activated whole‐cell currents. Moreover, the AMPA receptor subunit GluR‐BLc(Q) which forms spontaneously active homomeric channels with rectifying current‐voltage relationships, dominates the gating of heteromeric GluR‐BLc(Q)/GluR‐A(R) channels. The spontaneous currents of these heteromeric AMPAR channels show linear current–voltage relationships, and the ligand‐activated whole‐cell currents display slower deactivation and desensitization kinetics than the respective wild‐type channels. For heteromeric Lc‐mutated kainate and AMPA receptors, the effects on kinetics were reduced relative to the homomeric Lc‐mutated forms. Thus, an Lc‐mutated subunit can potentially influence heteromeric channel function in vivo, and the severity of the phenotype will critically depend on the levels of homomeric GluRLc and heteromeric GluRLc/GluRWT channels.