bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lesion Study of the Distribution of Serotonin 5‐HT4 Receptors in Rat Basal Ganglia and Hippocampus
Authors: Compan Valérie , Daszuta Annie , Salin Pascal , Sebben Michèle , Bockaert Joël , Dumuis Aline 
Published: April 2006

AbstractThe regional distribution of 5‐hydroxytryptamine (5‐HT4) receptors labelled with [3H]GR113808 was examined in rat basal ganglia and hippocampus after specific lesions. Lesion of serotonin neurons induced by injections of 5,7‐dihydroxytryptamine into the dorsal and medial raphe nuclei resulted in increased 5‐HT4 receptor binding in most regions examined, compared with controls. More precisely, there was a 78% increase in the rostral but no change in the caudal part of caudate‐putamen, and 83% and 54% increases in the shell and core of the nucleus accumbens respectively. In the substantia nigra, the increase in 5‐HT4 binding was larger (72%) than that in the globus pallidus (32%). In the hippocampus, 63%, 30% and 28% increases were measured in CA2, CA1 and CA3 respectively. Following lesion of dopamine neurons by intranigral injection of 6‐hydroxydopamine, increased 5‐HT4 receptor binding was observed in the caudal (59%), but not the rostral part of caudate‐putamen, as well as in the globus pallidus (93%). Since no decreases in 5‐HT4 receptor density were detected after the dopamine lesion, it was concluded that these receptors are not expressed in dopamine neurons. Kainic acid lesions of the caudate‐putamen were associated with dramatic local decreases in 5‐HT4 receptor binding on the injected side (‐89%), which suggested that striatal neurons express 5‐HT4 receptors. Corresponding decreases of 72 and 20% in receptor density were detected in globus pallidus and substantia nigra, consistent with a presumed localization of 5‐HT4 receptors on striatal GABA neurons projecting to these regions. In the substantia nigra, the decrease in [3H]GR113808 binding was localized to the pars lateralis, indicating that striatal neurons belonging to the cortico‐striato‐nigrotectal pathway, and containing GABA and dynorphin, express 5‐HT4 receptors.
Induction of Stat3, a Signal Transducer and Transcription Factor, in Reactive Microglia following Transient Focal Cerebral Ischaemia
Authors: Planas Anna M. , Soriano Marc A. , Berruezo Meritxell , Justicia Carles , Estrada Anna , Pitarch Silvia , Ferrer Isidre 
Published: April 2006

AbstractStat3, a member of the family of cytoplasmic signal transducers and activators of transcription, was found in the rat brain in vivo under physiological conditions and was stimulated following transient focal cerebral ischaemia. A transient episode of middle cerebral artery occlusion induced a strong microglial response in the areas undergoing neural cell death from 4 days after middle cerebral artery occlusion. This was accompanied by increased expression of Stat3 in the ipsilateral cortex and striatum, as revealed by Western blotting of tissue extracts. immunohistochemistry showed strong induction of Stat3 in reactive microglial cells 4, 7 and 15 days after cerebral ischaemia. Stat3 was seen in the microglia cytoplasm, but in many microglial cells immunoreactivity was also distributed within the nucleus. These results suggest that Stat3 mediates signal transduction and activates transcription in reactive microglia in vivo following brain ischaemia.
The Nitric Oxide/Cyclic GMP Messenger System in Olfactory Pathways of the Locust Brain
Authors: Bicker Gerd , Schmachtenberg Oliver , De Vente Jan 
Published: April 2006

AbstractNitric oxide is generated by a Ca2+/calmodulin‐stimulated nitric oxide synthase and activates soluble guanylyl cyclase. Using NADPH diaphorase (NADPHd) staining as a marker for the enzyme nitric oxide synthase and an antiserum against cGMP, we investigated the cellular organization of nitric oxide donor and target cells in olfactory pathways of the brain of the locust (Schistocerca gregaria). A small subset of neuronal and glial cells expressed cGMP immunoreactivity after incubation of tissue in a nitric oxide donor. Nitric oxide‐induced increases in cGMP immunoreactivity were quantified in a tissue preparation of the antennal lobe and in primary mushroom body cell cultures. The mushroom body neuropil is a potential target of a transcellular nitric oxide/ cGMP messenger system since it is innervated by extrinsic NADPHd‐positive neurons. The mushroom body‐intrinsic Kenyon cells do not stain for NADPHd but can be induced to express cGMP immunoreactivity. The colocalization of NADPHd and cGMP immunoreactivity in a cluster of interneurons of the antennal lobe, the principal olfactory neuropil of the insect brain, suggests a role of the nitric oxide/cGMP system in olfactory sensory processing. Colocalization of NADPHd staining and cGMP immunoreactivity was also found in certain glial cells. The cellular organization of the nitric oxide/cGMP system in neurons and glia raises the possibility that nitric oxide acts not only as an intercellular but also as an intracellular messenger molecule in the insect brain.
Sodium Current Amplitude Increases Dramatically in Human Retinal Glial Cells during Diseases of the Eye
Authors: Francke M. , Pannicke T. , Biedermann B. , Faude F. , Reichelt W. 
Published: April 2006

AbstractMüller cells, the main macroglial cells of the retina, express several types of voltage and ligand‐activated ion channels, including Na‐ channels. Using the whole‐cell voltage‐clamp technique, we studied the expression of Na‐ currents in acutely isolated, non‐cultivated human Muller cells from retinas of healthy organ donors and patients suffering from different eye diseases. In both types of retinas transient Na+ currents could be recorded from Muller cells. The tetrodotoxin‐resistant Na+ currents, which were not completely blocked even at a concentration of 10 $muM tetrodotoxin, had a mean current density of 3.0± 3.0 pA/pF (mean ± SD, n = 10) in Muller cells from donor retinas and of 12.2± 2 9.6 pA/pF (n= 74) in Muller cells from patient retinas. Only 33.3% of healthy but 88.4% of pathological Muller cells depicted such currents. The GNa+/GK+ ratio was very high in several Muller cells from patient retinas, such that action potential‐like activity could be generated after prehyperpolarizing current injection in some of these cells. Apparently, the Na’channels, due to their negative steady‐state inactivation curve (Vh= ‐84.5 mV), do not influence the lowered membrane potential of the pathological cells, since they are inactivated at these voltages. Currently, we do not have an explanation for the increase in amplitude and frequency of Na+ currents in human Muller cells under pathological conditions. However, the up‐regulation of Na channels may mirror a basic glial response to pathological conditions, since it has also been found previously in human hippocampal astrocytes from epileptic foci and in rat cortex stab wounds lined by an astrocytic scar.
Rat Brain: Distribution of Immunoreactivity of PE‐11, a Peptide Derived from Chromogranin B
Authors: Kroesen S. , Marksteiner J. , Leitner B. , Hogue‐Angeletti R. , Fischer‐Colbrie R. , Winkler H. 
Published: April 2006

AbstractAn antiserum was raised against the peptide PE‐11 whose sequence is present in the chromogranin B molecule. The antiserum reacts only with the free C‐terminal end of this peptide. PE‐11 immunoreactivity in brain was characterized by molecular size exclusion high performance liquid chromatography. Only the free peptide and a N‐terminally elongated peptide were detected, indicating that proteolytic processing of chromogranin B in brain is quite extensive. In immunohistochemistry PE‐11 immunoreactivity was found in varicosities, fibres and perikarya throughout the brain. Strong staining was detected in the shell sector of the nucleus accumbens, in the lateral septum, in subregions of the extended amygdala, in some areas of the hippocampus and of the hypothalamus, in the locus coeruleus, in the Purkinje cells of the cerebellum and in the dorsal horn of the spinal cord. Our results, which demonstrate significant processing of chromogranin B in brain and its widespread distribution, can be taken as an indication that chromogranin B represents a precursor of peptides with functional relevance for this organ.
Developmental Study of N‐Methyl‐d‐Aspartate‐induced Firing Activity and Whole‐cell Currents in Nucleus Tractus Solitarii Neurons
Authors: Vincent Anne , Jean André , Tell Fabien 
Published: April 2006

AbstractWhole‐cell recordings of rat nucleus tractus solitarii (NTS) neurons were performed on a slice preparation. We investigated possible postnatal changes in firing activities and currents induced by N‐methyl‐d‐aspartate (NMDA) application. A total of 42 neurons were selected and fell into the following age groups: 0‐5 days (n= 15), 10‐15 days (n= 9) and 30‐60 days (adult, n= 18). During this period, input resistance and spike duration decreased by‐˜40%. At all ages, bath application of NMDA elicited a bursting firing activity when the membrane potential was held between ‐60 and ‐75 mV. However, in the youngest cells the rhythmic bursting activity was irregular and was characterized by a progressive firing inactivation during a burst. In a tetrodotoxin‐containing saline, NMDA‐induced oscillations of membrane potential were retained in all age groups. The membrane current‐voltage relationship of the NMDA‐induced inward current (INMDA) was characterized by a region of negative slope conductance which was similar in all age groups. Thus the voltage‐dependent block of INMDA is present in NTS neurons from birth, allowing NTS neurons to display membrane potential oscillations. However, postnatal maturation of repolarizing conductances, as suggested by changes in spike characteristics, could render the oscillatory activity more stable than at birth.
Characterization of a Distinctive Motif of the Low Molecular Weight Neurotrophin Receptor that Modulates NGF‐mediated Neurite Growth
Authors: Dostaler S. M. , Ross G. M. , Myers S. M. , Weaver D. F. , Ananthanarayanan V. , Riopelle R. J. 
Published: April 2006

AbstractThe cytoplasmic region of the common neurotrophin receptor (p75NGFR) (rat, human, chick) contains a putative membrane‐associating domain implicated in intracellular signalling. A peptide (R3) identical to this domain (p75NGFR 367–379) and various analogues of this peptide displayed circular dichroism spectra in aqueous and non‐polar environments identical to the amphiphilic tetradecapeptide mastoparan (MP) and were internalized by PC12 rat pheochromocytoma cells. The R3 peptide enhanced neurite growth in PC12 cells, embryo chick primary sensory neurons and fetal rat primary sensory neurons in vitro in the presence of sub‐saturating concentrations of NGF. Peptide analogues of R3 not faithful to the distance and angular relationships of ionic groups and the putative amphiphilic structure of p75NGFR 367–379 displayed reduced potency to enhance NGF‐mediated neurite growth. Exposure of NGF and the R3 peptide to a cell line displaying predominantly p75NGFR (PC12nnr5), had no influence on neurite growth. The R3 peptide had no effects on cell survival, cell binding or uptake of [125I]NGF, affinity cross‐linking of [125I]NGF to p75NGFR or trkA monomers and homodimers, or NGF‐mediated trkA monomer tyrosine phosphorylation. The studies implicate a role for a highly conserved motif of p75NGFR in the downstream modulation of NGF‐mediated neurite growth.
Cranial Motor Axons Respond Differently to the Floor Plate and Sensory Ganglia in Collagen Gel Co‐cultures
Authors: Tucker Anna , Lumsden Andrew , Guthrie Sarah 
Published: April 2006

AbstractWithin the developing chick hindbrain, motor neurons differentiate in columns on either side of the ventral midline floor plate. Along the rostrocaudal axis, populations of motor neurons are organized segmentally with the trigeminal (V) and facial (VII) nuclei occupying successive pairs of rhombomeres. To reach their targets, motor axons follow stereotyped pathways. Branchiomotor and visceral motor axons of the Vth and VIIth nerves first project in a dorsal (lateral) direction away from the floor plate and towards the nerve exit point located in the alar plate of the even‐numbered rhombomere of the pair. Having exited the hindbrain, axons grow in association with the cranial sensory ganglia before branchiomotor axons enter the branchial arches. We have investigated some of the factors that might guide cranial motor axons using a three‐dimensional collagen gel culture system. When explants of hindbrain basal plate containing trigeminal or facial motor neurons were co‐cultured with floor plate explants, axon outgrowth from the side facing the floor plate was inhibited in a manner consistent with chemorepulsion. When basal plate explants that contained an exit point were cultured alone, motor axons grew to the exit point and then stopped. When basal plate explants were co‐cultured with trigeminal ganglia, motor outgrowth was increased in comparison with that in control cultures, suggesting a trophic influence. The findings presented here indicate that motor pathways are elaborated due to a progression of signals to which the growth cones respond in sequence.
Involvement of γ and β Actin Isoforms in Mouse Neuroblastoma Differentiation
Authors: Ulloa Luis , Avila Jesus 
Published: April 2006

AbstractTwo actin isoforms, γ and β, are contained within neuroblastoma cells. However, the relative amount and distribution of both isoforms within the cells are differentially regulated during neurite extension. The proportion of γ actin isoform became about four times greater than that of β actin during neuroblastoma cell differentiation. Additionally, whereas β actin appears to be concentrated in the cell cortex, γ actin is also present throughout the cell body. Upon differentiation, neuroblastoma cells reorganize their actin cytoskeleton and γ actin is induced to polymerize whereas β actin polymers are partially disassembled. Moreover, both actin isoforms are differentially distributed within differentiated cells. Thus, γ actin polymers are located both in the soma and proximal regions of extended neurites, whereas β actin is enriched in the terminal tip of the neurites. Our results strongly suggest that both actin isoforms are involved in a different way in neuroblastoma cell differentiation.
Mossy Cells of the Rat Dentate Gyrus are lmmunoreactive for Calcitonin Gene‐related Peptide (CGRP)
Authors: Freund Tamás F. , Hájos Norbert , Acsády László , Górcs Tamás J. , Katona István 
Published: April 2006

AbstractThe neuropeptide calcitonin gene‐related peptide (CGRP) was localized in the hippocampus and dentate gyrus of the rat by immunocytochemistry at the light and electron microscopic levels. Without colchicine treatment only faint neuropil labelling was found in the inner molecular layer of the dentate gyrus. Following colchicine treatment, a large number of neurons with numerous complex spines along the proximal dendrites were visualized in the hilus of the dentate gyrus, particularly in the ventral areas, and, in addition, staining of the inner molecular layer became stronger. Several CA3c pyramidal cells located adjacent to the hilar region in the ventral hippocampus also appeared to be faintly positive, although in most cases only their axon initial segments were labelled. Outside this region, the subicular end of the CA1 subfield contained occasional CGRP‐positive non‐pyramidal cells. The hilar CGRP‐positive neurons were negative for parvalbumin, calretinin, cholecystokinin and somatostatin, whereas most of them were immunoreactive for GluR2/3 (the AMPA‐type glutamate receptor known to be expressed largely by principal cells). Correlated electron microscopy showed that the spines along the proximal dendritic shafts indeed correspond to thorny excrescences engulfed by large complex mossy terminals forming asymmetrical synapses. Pre‐embedding immunogold staining demonstrated that CGRP immunoreactivity in the inner molecular layer was confined to axon terminals that form asymmetrical synapses, and the labelling was associated with large dense‐core vesicles. The present data provide direct evidence that CGRP is present in mossy cells of the dentate gyrus and to a lesser degree in CA3c pyramidal cells of the ventral hippocampus. These CGRP‐containing principal cells terminate largely in the inner molecular layer of the dentate gyrus, and may release the neuropeptide in conjunction with their ‘classical’ neurotransmitter, glutamate.
Differential Effects of lntrastriatal Neurotensin(1–13) and Neurotensin(8–13) on Striatal Dopamine and Pallidal GABA Release. A Dual‐probe Microdialysis Study in the Awake Rat
Authors: Ferraro Luca , O'Connor William Thomas , Antonelli Tiziana , Fuxe Kjell , Tanganelli Sergio 
Published: April 2006

AbstractIn the present dual‐probe microdialysis study the effects of intrastriatal perfusion with the tridecapeptide neurotensin(1–13) [NT(1–13)] and its active fragment NT(8–13) on striatopallidal GABA and striatal dopamine release were investigated. The modulatory action of NT(1–13) on D2 receptor‐mediated inhibition of striatal and pallidal GABA release was also studied. Both intrastriatal NT(1–13) (100 nM) and NT(8–13) (100 nM) increased striatal (139 and 149% respectively) and pallidal (130 and 164%) GABA release, and this effect was antagonized by intrastriatal perfusion with the neurotensin receptor antagonist SR48692 (100 nM). A similar increase (155%) in striatal dopamine release was observed following intrastriatal NT(1–13) (100 nM), but not NT(8–13) (100 and 500 nM). However, at the highest concentration studied (1 μM) NT(8–13) was associated with a rapid increase (130%) in striatal dopamine release. In a second study intrastriatal NT(1–13) (10 nM) counteracted the inhibition of striatal and pallidal GABA release induced by pergolide (500 and 1500 nM). The inhibitory action of the D2 agonist was restored when SR48692 (100 nM) was added to the perfusion medium. These results suggest that in the neostriatum the neurotensin receptor located postsynaptically on the striatopallidal GABA neurons seems to differ from the neurotensin receptor located on dopaminergic terminals, as indicated by the relative lack of effect of NT(8–13) on striatal dopamine release. Furthermore, the ability of NT(1–13) to counteract the pergolide‐induced inhibition of both striatal and pallidal GABA release strengthens the evidence for antagonistic receptor‐receptor interaction between postsynaptic striatal neurotensin and D2 receptors located on striatopallidal GABA neurons.
Non‐synaptic Localization of the Glutamate Transporter EAACI in Cultured Hippocampal Neurons
Authors: Coco Silvia , Verderio Claudia , Trotti Davide , Rothstein Jeffrey D. , Volterra Andrea , Matteoli Michela 
Published: April 2006

AbstractIt has been postulated for several years that the high affinity neuronal glutamate uptake system plays a role in clearing glutamate from the synaptic cleft. Four different glutamate transporter subtypes are now identified, the major neuronal one being EAAC1. To be a good candidate for the reuptake of glutamate at the synaptic cleft, EAAC1 should be properly located at synapses, either at pre‐ or postsynaptic sites. We have investigated the distribution of EAAC1 in primary cultures of hippocampal neurons, which represent an advantageous model for the study of synaptogenesis and synaptic specializations. We have demonstrated that EAAC1 immunoreactivity is segregated in the somatodendritic compartment of fully differentiated hippocampal neurons, where it is localized in the dendritic shaft and in the spine neck, outside the area facing the active zone. No co‐localization of EAAC1 immunoreactivity with the stainings produced by typical presynaptic and postsynaptic markers was ever observed, indicating that EAAC1 is not to be considered a synaptic protein. Accordingly, the developmental pattern of expression of EAAC1 was found to be different from that of typical synaptic markers. Moreover, EAAC1 was expressed in the somatodendritic compartment of hippocampal neurons already at stages preceding the formation of synaptic contacts, and was also expressed in GABAergic interneurons with identical subcellular distribution. Taken together, these data rule against a possible role for EAAC1 in the clearance of glutamate from within the cleft and in the regulation of its time in the synapse. They suggest an unconventional non‐synaptic function of this high‐affinity glutamate carrier, not restricted to glutamatergic fibres.
Light‐induced c‐Fos Expression in the Mouse Suprachiasmatic Nucleus: Immunoelectron Microscopy Reveals Co‐localization in Multiple Cell Types
Authors: Castel Mona , Belenky Michael , Cohen Shulamith , Wagne Shlomo , Schwartz William J. 
Published: April 2006

AbstractAlthough light is known to regulate the level of c‐fos gene expression in the suprachiasmatic nucleus (SCN), the site of an endogenous circadian clock, little is known about the identities of the photically activated cells. We used light‐microscopic immunocytochemistry and immunoelectron microscopy to detect c‐Fos protein in the SCN of Sabra mice exposed to brief nocturnal tight pulses at zeitgeber time 15–16. Stimulation with light pulses that saturated the phase‐shifting response of the circadian locomotor rhythm revealed an upper limit to the number of photo‐inducible c‐Fos cells at about one‐fifth of the estimated total SCN cell population. This functionally defined set was morphologically and phenotypically heterogeneous. About 24% could be labelled for vasoactive intestinal polypeptide, 13% for vasopressin‐neurophysin, and 7% for glial fibrillary acidic protein. The remaining 56% of c‐Fos‐positive cells were largely of unknown phenotype, although many were presumptive interneurons, some of which were immunoreactive for nitric oxide synthase.
Effect of Body Orientation with Respect to Gravity on Directional Accuracy of Human Pointing Movements
Authors: Smetanin B. N. , Popov K. E. 
Published: April 2006

AbstractErrors in pointing to remembered target locations were measured in normal subjects in the upright posture and in a supine or prone lying position, three conditions that differed in the orientation of the moving arm with respect to gravity. Vertical errors, or, more strictly, errors along the body axis, were significantly larger in both supine and prone lying positions as compared with the vertical posture. Subjects’ orientation with respect to gravity produced a consistent error pattern, i.e. subjects pointed below the remembered target locations in the vertical posture and above them under the two lying conditions, in the body‐related co‐ordinates. On the contrary, variable error (the confidence ellipse) was differentially affected by the orientation of the movement trajectory with respect to gravity. In the supine body position the variable error was larger, and in the prone position it was smaller than in the upright posture. The finding of gravity‐related bias in pointing errors suggests that the motor programme generated in the lying position is not modified to adapt to an altered orientation with respect to gravity.