bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sprouting and Regeneration of Lesioned Corticospinal Tract Fibres in the Adult Rat Spinal Cord
Authors: Schnell L. , Schwab M. E. 
Published: April 2006

AbstractWe have studied the effects of tissue transplants and antibodies (IN‐1) against the myelin‐associated neurite growth inhibitory proteins on sprouting and regeneration of the rat corticospinal tract (CST). Transplantation of embryonic spinal cord tissue into bilateral transection lesions of the lower thoracic spinal cord in young adult rats resulted in a marked increase of the sprouting of the lesioned CST. This sprouting effect was probably elicited by soluble factors released from the transplants, and was enhanced by the IN‐1 antibodies. The retraction of lesioned CST fibres normally observed with prolonged survival times was also reduced by the presence of transplants. In spite of these growth‐promoting effects of the transplants, the regenerative elongation of CST sprouts into the caudal spinal cord was dependent upon the neutralization of the myelin‐associated inhibitory proteins. In the controls (no antibodies or control antibodies) only 27% of the animals showed elongation of CST fibres exceeding the sprouting distance of 0.7 mm. These fibres grew to a maximal length of 1.8 mm (mean±SEM, 1.2±0.1). In contrast, 60% of the IN‐1‐treated, transplant‐containing rats showed elongations of >0.7 mm, and these fibres grew up to 10.1 mm (4.6±0.5). Regenerating fibres crossed the lesion site through remaining tissue bridges. Neither embryonic spinal cord transplants nor a variety of implanted bridge materials could serve as a substrate for the regenerating CST axons.
Two Signal Transduction Mechanisms of Substance P‐induced Depolarization in Locus Coeruleus Neurons
Authors: Koyano K. , Velimirovic B. M. , Grigg J. J. , Nakajima S. , Nakajima Y. 
Published: April 2006

AbstractEffects of substance P on cultured neurons of the locus coeruleus of the rat were studied using the whole‐cell patch clamp technique. In some cells substance P produced a decrease in a K conductance which showed an inwardly rectifying property. In other cells substance P produced an initial inward current which was accompanied by a conductance increase. The rest of the cells showed responses which were mixtures of the above two responses. The measurement of the reversal potential of the initial inward current after suppressing the voltage‐gated Ca and K conductances suggests that it is caused by an increase in a non‐selective ionic conductance. In cells loaded with 260 μM GTPγS, application of substance P produced an irreversible reduction of the K conductance, while the initial inward current could still be recorded, suggesting that the former is mediated by a G protein, whereas the latter may be activated by a different signal transduction mechanism. The initial inward current was not eliminated by external application of high concentrations of tetrodotoxin, d‐tubocurarine or amiloride. Nor was it affected by the intracellular application of cyclic GMP or cyclic AMP.
Fos Immunoreactivity after Stimulation or Inhibition of Muscarinic Receptors Indicates Anatomical Specificity for Cholinergic Control of Striatal Efferent Neurons and Cortical Neurons in the Rat
Authors: Bernard Véronique , Dumartin Brigitte , Lamy Eliette , Bloch Bertrand 
Published: April 2006

AbstractCholinergic neurons play a major role in the control of striatal activity via muscarinic receptors. The action of acetylcholine also appears to be dependent on the striosome – matrix compartmentalization of the striatum. This study was designed to find out whether modification of acetylcholine tone activates neurons in the striatum and forebrain of the rat. We looked for the appearance of immunoreactivity to Fos, a regulatory protein that is thought to convert synaptic signals into changes in gene expression. Pharmacological manipulation of muscarinic receptors was found to induce specific patterns of Fos immunoreactivity in distinct neuronal populations of the forebrain, including the striatum. Oxotremorine, a non‐selective muscarinic agonist, induced Fos immunoreactivity in the striatum with a large predominance in striosomes (mostly in enkephalinergic neurons), in layers 4 and 6 of the cortex, and also in the piriform cortex and septum. The muscarinic agonist pilocarpine had an identical effect in the cortex, but the striosomal prevalence was less clear‐cut than that observed after oxotremorine. Treatment with dopamine‐depleting agents (6‐hydroxydopamine or reserpine) and inhibitors of glutamate and opiate receptor (MK‐801 and naloxone respectively) had no effect on the action of oxotremorine. This suggests that the induction of Fos provoked by oxotremorine does not involve dopamine, glutamate or opiates. Atropine, a non‐specific muscarinic antagonist, also induced Fos immunoreactivity in the striatum but with matrix predominance (mostly in substance P neurons), as well as in the cingulate cortex, and the olfactory tubercle. Scopolamine, a muscarinic antagonist, induced Fos in both striosomal and matrix compartments in the striatum. No Fos immunoreactivity was observed after change in acetylcholine tone in cholinergic or somatostatinergic neurons of the striatum, or in dopaminergic neurons of the substantia nigra. Our results demonstrate that stimulation or inhibition of muscarinic receptors induces Fos activation in striatal efferent neurons with topological (striosome/matrix) and phenotypical (enkephalin/substance P) prevalence and specificity and also in cortical neurons with also topological prevalence. These data suggest that in humans, direct or indirect modifications of the cholinergic neurotransmission induced by pathological states or by drugs may lead to neuronal events in the forebrain triggered by Fos activation.
The Role of Serotonin Receptor Subtypes in the Behavioural Effects of Neuroleptic Drugs. A Paw Test Study in Rats
Authors: Ellenbroek Bart A. , Prinssen Eric P. M. , Cools Alexander R. 
Published: April 2006

AbstractThe present study was designed to evaluate the roles of serotonin 5‐HT1A and 5‐HT2 receptors in the effects of neuroleptic drugs in the paw test. This behavioural test has been shown to model both the antipsychotic efficacy as well as the extrapyramidal side‐effect liability of neuroleptic drugs. Whereas the 5‐HT1A receptor agonist 8‐hydroxy‐2‐(di‐n‐propylamino)tetralin (8‐OHDPAT) reduced the effects of the classical neuroleptic haloperidol, it increased the effects of the atypical neuroleptic clozapine. The 5‐HT2 receptor antagonist ketanserin as well as the 5‐HT1C/5‐HT2 receptor antagonist ritanserin, on the other hand reduced the effects of haloperidol, whereas the 5‐HT1C/5‐HT2 receptor agonist 1‐(2,5‐dimethoxy‐4‐iodophenyl)‐2‐aminopropane (DOl) reduced the effects of clozapine. The most important finding, however, was that the behavioural effects of different (putative) neuroleptics (fluphenazine, SCH‐39166, remoxipride, prothipendyl, thioridazine and risperidone) were differentially influenced by both 8‐OHDPAT and DOl, suggesting that there are important differences between the neuronal mechanisms underlying the behavioural effects of these neuroleptic drugs, even within the subclasses of classical and atypical neuroleptics.
Heterogeneity Among Neuroepithelial Cells in the Chick Retina Revealed by Immunostaining with Monoclonal Antibody PM1
Authors: Hernández‐Sánchez Catalina , Frade José M. , de La Rosa Enrique J. 
Published: April 2006

AbstractNeuroepithelial cells appear as a homogeneous population of cells in the cell cycle that seem to behave as pluripotent neural precursors. The study of the intrinsic heterogeneity and subtle developmental changes among neuroepithelial cells has been hindered by the lack of specific markers. To address that study, a panel of monoclonal antibodies was produced against early developing chick retina. The monoclonal antibody precursor marker 1 (PM1) labels most, if not all, of the early neuroepithelial cells in embryonic day 4 retinal sections. This pattern is transient since the labelling becomes restricted to the peripheral retina as development proceeds and eventually disappears from the neuroepithelial cells. However, apparently in parallel, the differentiating retinal ganglion cells become PM1‐positive. The expression of the PM1 antigen, a 73 × 103Mr protein, as shown by western blotting, also decreases with development. In addition, a chick retina dissociated‐cell culture system, where retinal neuroepithelial cells actively proliferate and undergo differentiation under defined conditions, in combination with monoclonal antibody PM1, allowed us to characterize and quantify the proliferating and differentiating neuroepithelial cells. Interestingly, the fraction of total neuroepithelial cells that are stained with PM1 sharply decreases as retinal development proceeds, in correlation with the staining pattern in sections from matched stages. These data thus reveal that the pluripotent neural precursors in the chick retina already represent an intrinsically heterogeneous population, and that this population changes with development.
Lamellar Organization of Pontocerebellar Neuronal Populations. A Multi‐tracer and 3‐D Computer Reconstruction Study in the Cat
Authors: Nikundiwe Alfeo M. , Bjaalie Jan G. , Brodal Per 
Published: April 2006

AbstractThis study deals with the three‐dimensional arrangement of populations of pontocerebellar cell bodies projecting to the parafloccular complex. The fluorescent tracers rhodamine B isothiocyanate, fluoro‐gold and fast blue were injected in either adjacent or separated cerebellar folia. A set of coordinates (x, y, z) was assigned to each retrogradely labelled cell and the total distribution reconstructed and displayed on a graphics workstation. At a large scale, we found that the majority of the cells of each labelled population (all projecting to the same folium) were confined to a lamella‐shaped tissue volume. Each lamella extended from medial to lateral, and accordingly followed the curving of the pontine grey around the corticospinal and corticobulbar fibre tracts. At a smaller scale, i.e. within each lamellar subspace, the neurons belonging to one labelled population were distributed in aggregates of various shapes. To enable further analysis of the shapes of the intralaminar aggregates, we developed a computer program for unfolding of the lamellae, based on cubic B‐spline approximation. The flattened reconstructions were three‐dimensional polygonal windows, circumscribing the large majority of the labelled cell swarm (usually 70–80% of the total number of labelled cells in one population). The present findings, taken together with previous data on a gradual, rather than disjunctive, shift of pontocerebellar neuronal position in relation to a gradual shift of target region (Bjaalie et al., Anat Rec, 231, 510–523, 1991), suggest that the cerebropontocerebellar system may be organized according to a set of fairly simple topographic rules.
Release of Acetylcholine and Noradrenaline from the Cholinergic and Adrenergic Afferents in Rat Hippocampal CA1, CA3 and Dentate Gyrus Regions
Authors: Milusheva E. , Baranyi M. , Zelles T. , Mike Á. , Vizi E. S. 
Published: April 2006

AbstractAn attempt was made to study the release of acetylcholine (ACh) and noradrenaline and their presynaptic modulation in isolated slice preparations dissected from different subfields of the hippocampus: CA1, CA3 and the dentate gyrus. The slices were perfused and loaded with [3H]choline or with [3H]noradrenaline. The release in response to field stimulation was determined radiochemically and the content of transmitters was assayed by a chemiluminescent method or by HPLC combined with electrochemical detection. After 30 min of loading with [3H]choline there were marked subregional differences in the specific activity of [3H]ACh content. The highest concentration was measured in the dentate gyrus and the lowest in CA3. Evidence was obtained that in all three subfields the cholinergic axon terminals are equipped with inhibitory muscarinic autoreceptors and the noradrenergic terminals with α2‐autoreceptors, as indicated by an increase in transmitter release when the tissue was exposed to selective muscarinic or α2‐adrenoceptor antagonists. In contrast, the cholinergic boutons are not equipped with α2‐adrenoceptors, and noradrenergic terminals do not possess inhibitory muscarinic receptors. It is therefore concluded that while the release of both ACh and noradrenaline is controlled by negative feedback modulation, there is no possibility of establishing a presynaptic inhibitory interaction between the two.
Temporal Structure of a Bimanual Goal‐directed Movement Sequence in Monkeys
Authors: Kazennikov O. , Wicki U. , Corboz M. , Hyland B. , Palmeri A. , Rouiller E. M. , Wiesendanger M. 
Published: April 2006

AbstractThe aim of the present investigation was to assess a bimanual goal‐oriented movement sequence with particular emphasis on its temporal structure. The three monkeys (Macaca fascicularis) used in this study chose the left arm as the leading and more postural arm to reach out and pull back a spring‐loaded drawer containing a food morsel. The right arm followed the left and picked up the food with a precision grip. Video recordings, trajectory recordings of the two index fingers, drawer displacement and the measurements of discrete events of the left and right hand revealed a considerable trial‐by‐trial variability in the temporal and spatial domain. The variability of latencies progressively increased from the initiation of the bimanual sequence to the left‐hand and right‐hand events defining goal achievement. The main result was that, in spite of this variability in each of the two limbs, there was an invariant left‐right goal‐related synchronization. The timing of the goal‐related event pairs covaried and showed high correlation coefficients. Covariation of the two hands resulting in an invariant synchronization was particularly striking when monkeys performed the task without vision, and timing of right and left movement components was delayed with further increase in variability. The results indicate that, in the present bimanual skill, kinaesthetic signals may be sufficient to coordinate the two limbs in a goal‐oriented unitary action in accord with a memorized plan.
trkC‐like Immunoreactivity in the Primate Descending Serotoninergic System
Authors: Arvidsson Ulf , Risling Mårten , Frisén Jonas , Piehl Fredrik , Fried Kaj , Hökfelt Tomas , Cullheim Staffan 
Published: April 2006

AbstractIn the search for substances with a potential role in plastic responses of spinal motoneurons we have studied the distribution of trkC‐like immunoreactivity in the spinal cord of adult monkeys (Macaca fascicularis). The presence of trkC, which is a signal‐transducing receptor for neurotrophin‐3, was detected by the use of indirect immunofluorescence with a rabbit polyclonal antibody raised against a synthetic peptide corresponding to the carboxy‐terminal domain of the mouse trkC‐encoded protein, thus detecting only full‐length signal‐transducing receptors.trkC‐immunoreactive fibres/varicosities could be found at all spinal cord levels and the densest innervation was found in the autonomic intermediolateral and Onuf's nuclei, but somatic motoneuron pools also received a significant contribution of trkC‐immunoreactive fibres. Terminals immunoreactive for trkC were also seen in the dorsal horn. Double‐labelling experiments revealed a high degree of coexistence between trkC‐ and 5‐hydroxytryptamine (serotonin)‐like immunoreactivity in all areas except in the dorsal horn. The results of the present study suggest that neurotrophic signalling with an influence on serotoninergic as well as non‐serotoninergic inputs to the adult monkey spinal cord is at hand.
Blockade of Prefronto‐cortical α1‐Adrenergic Receptors Prevents Locomotor Hyperactivity Induced by Subcortical D‐Amphetamine Injection
Authors: Blanc G. , Trovero F. , Vezina P. , Hervé D. , Godeheu A.‐M. , Glowinski J. , Tassin J.‐P. 
Published: April 2006

AbstractThe stimulation of cortical dopaminergic D1 receptors can counteract the increased locomotor activity evoked by D‐amphetamine application in the nucleus accumbens (Vezina et al., Eur. J. Neurosci., 3, 1001–1007, 1991). Moreover, an α1 antagonist, prazosin, prevents the locomotor hyperactivity induced by electrolytic lesions of the ventral tegmental area (Trovero et al., Neuroscience, 47, 69–76, 1992). Attempts were thus made to see whether blockade of α1‐adrenergic receptors in the rat prefrontal cortex could reduce nucleus accumbens D‐amphetamine‐evoked locomotor activity. Rats implanted chronically and bilaterally with cannulae into the medial prefrontal cortex and the nucleus accumbens were used for this purpose and locomotor activity was monitored in circular corridors. Preliminary experiments indicated that intraperitoneal injection of prazosin (0.06 mg/kg) reduces the locomotor hyperactivity induced by the peripheral administration of D‐amphetamine (0.75 mg/kg). This effect of prazosin was not observed when locomotor hyperactivity was obtained by an intraperitoneal injection of scopolamine (0.8 mg/kg). Bilateral nucleus accumbens injections of D‐amphetamine (4.0 nmol/side) markedly increased locomotor activity, as estimated in a 30 min period. Prior (20 min) bilateral injections of either prazosin or WB‐4101 (0.16 pmol) into the medial prefrontal cortex abolished the nucleus accumbens D‐amphetamine‐evoked response. The recovery of the nucleus accumbens D‐amphetamine‐evoked response was closely dependent on the amount of prazosin used, very prolonged inhibitory effects of the drug being seen with a high amount (>4 days with 160 pmol). In contrast, whatever the amount of WB‐4101 used (0.16–160 pmol), recovery occurred within 3 days. It is suggested that the blockade of cortical d‐adrenergic receptors facilitates locally dopaminergic D1 transmission. This latter effect may counteract the increased locomotor activity induced by the application of D‐amphetamine into the nucleus accumbens.
Increases in Neuronal Bursting Recorded From the Chick Lobus Parolfactorius After Training Are Both Time‐dependent and Memory‐specific
Authors: Gigg John , Patterson Teresa A. , Rose Steven P. R. 
Published: April 2006

AbstractDay‐old‐chicks can be trained in one trial to avoid a methylanthranilate‐coated bead (methyl‐chicks). The lobus parolfactorius of the chick forebrain is an important structure for memory of this avoidance response. To examine training‐induced electrophysiological changes in this structure, spontaneous neuronal bursting activity was measured from the lobus parolfactorius of anaesthetized, day‐old methyl‐ and water‐chicks (the latter chicks trained to peck at a water‐coated bead) over the period 1 – 10 h post‐test. Bursting was significantly higher in methyl‐chicks over this period. This post‐test increase was time‐dependent: bursting in methyl‐chicks was significantly higher only during the period 4–7 h post‐test. In a second experiment, methyl‐chicks were subjected to brief, subconvulsive electroshock 5 min post‐training. When tested 1 h later about half of these chicks showed recall (avoided the bead) and half were amnesic (pecked the bead). These chicks were anaesthetized and bursting was recorded from the lobus parolfactorius. Chicks that showed recall exhibited a significantly higher level of bursting over the period 1 – 10 h post‐test when compared to chicks that were amnesic. The time course of bursting was similar to that seen in non‐electroshocked methyl‐chicks. These results suggest that passive avoidance training induces a memory‐specific, time‐dependent increase in neuronal activity within the lobus parolfactorius of day‐old chicks. This increase may be directly associated with long‐term consolidation of memory for the task.
Altered Calcitonin Gene‐related Peptide, Substance P and Enkephalin Immunoreactivities and Receptor Binding Sites in the Dorsal Spinal Cord of the Polyarthritic Rat
Authors: Kar S. , Rees R. G. , Quirion R. 
Published: April 2006

AbstractThe dorsal horn of the spinal cord, which forms the locus of first synapses in pain pathways, is an important site of interaction between calcitonin gene‐related peptide (CGRP), substance P and enkephalin—the neuropeptides considered to be especially involved in the regulation of pain perception. Since adjuvant‐induced arthritic rats provide a suitable model for peripheral inflammation and hyperalgesia, the possible alterations of immunoreactive CGRP, substance P and enkephalin as well as the binding sites for [125I]hCGRPα, [125I]substance Plneurokinin‐1, (NK1) and [125I]FK‐33‐824/μ‐opioid receptors were studied in the dorsal horn of the spinal cord receiving projections from the inflamed limbs. In arthritic rats compared to control animals, a bilateral increase in CGRP‐ and substance P‐immunoreactive fibres and the presence of enkephalin‐immunoreactive cell bodies were noted in the dorsal horn of the spinal cord. As for receptors, while a significant decrease in [125I]hCGRPα and [125I]substance P/NK1 binding sites was observed in selective layers, no measurable alteration in [125I]FK‐33‐824/μ‐opioid binding sites was noted in any regions of the arthritic rat dorsal horn compared to the unaffected control rats. Following unilateral section of the peripheral nerve prior to induction of arthritis, CGRP‐ and substance P‐immunoreactive fibres were markedly depleted and no enkephalin‐positive neurons were observed in the ipsilateral dorsal horn. Analysis of receptor binding sites in denervated arthritic rats, however, exhibited differential responses, i.e. a significant increase in [125I]hCGRPα, a marked decrease in [125I]FK‐33‐824/μ‐opioid and apparently no alteration in [125I]substance P/NK1 receptor binding sites were observed in the ipsilateral dorsal horn compared to the intact contralateral side. These results taken together provide anatomical evidence for a concerted role of these peptides in the regulation of adjuvant‐induced hyperalgesia accompanying peripheral inflammation.
Relationship Between Tyrosine Hydroxylase Content and Noradrenergic Cell ‐Reactivity to Piperoxane: an In Vivo Voltammetric Approach in the Rat Locus Coeruleus
Authors: Vachette Cédric , Debure Laure , Rousset Colette , Pujol Jean‐François , Renaud Bernard 
Published: April 2006

AbstractA previous electrochemical study showed that the increase in the tyrosine hydroxylase (TH) content of the locus coeruleus (LC) produced by RU24722 administration was associated with a relative decrease in the catecholaminergic metabolic reactivity of this nucleus to a hypotensive stimulus. Since α2 receptors participate in the regulation of the activity of both LC neurons and TH, the aim of the present work was to evaluate the possible involvement of the autoinhibition mediated by α2, autoreceptors in the inverse relationship between the reactivity of the LC and its TH content. Our study was divided into two successive steps: (i) the electrochemical measurement of the in vivo metabolic activation of LC cells in response to α2,‐adrenergic receptor blockade, and (ii) the evaluation of the quantity of TH every 100 μm along the caudo‐rostra1 axis in each recorded LC. The capacity of TH protein to be activated was evaluated by the measurement, using differential normal pulse voltammetry, of the in vivo variations of the extracellular 3, 4‐dihydroxyphenylacetic acid concentrations in response to six cumulated doses of the α2,‐antagonist piperoxane. The corresponding dose‐response curves, determined in control‐and RU24722‐treated rats, were expressed as a function of the quantity of TH contained either in the whole recorded LC or in the 100 μm‐wide coronal interval surrounding the recording site. It was established that the slopes of the dose‐response curves were significantly (P < 0.01) and inversely related to the quantity of TH at the level of the recording site. This result suggests that the negative control of the catecholaminergic metabolic reactivity in a restricted area of the LC could be directly or indirectly dependent on the level of expression of TH protein in this particular area.