bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corticonuclear projections of the cerebellum preserve both anteroposterior and mediolateral pairing patterns
Authors: Pantò M. R. , Zappalà A. , Parenti R. , Serapide M. F. , Cicirata F. 
Published: March 2003

AbstractThe aim of the present study was to establish whether a diverging arrangement of the corticonuclear cerebellar projections exists and, if so, what relation it has with the inferior olivary complex. Iontophoretic injections of a 1 : 1 mixture of tetramethylrhodamine dextran amine and byotinilated dextran amine into the cerebellar cortex orthogradely labelled fibre terminals in the cerebellar nuclei and retrogradely labelled cell bodies in the inferior olivary complex. The injections were into A, B, C2, C3, D1 and D2 bands. These injections showed diverging projections to the cerebellar nuclei, with ‘primary projections’ directed to the nuclear region previously reported to be specifically connected with the injected band and ‘secondary projections’ directed to other nuclear regions. Secondary projections from the A, C2 and C3 bands diverged to nuclear regions primarily controlled by cortical bands lateral to those injected. Secondary projections from the D1, and D2 bands diverged to nuclear regions primarily controlled by cortical bands medial to those injected. Moreover, injections distributed along the D1 and D2 bands showed similar sets of nuclear targets, while those distributed along the A, C2 and C3 bands showed two sets of nuclear targets in relation to the anteroposterior location of the injected area within these bands. The cortical areas that projected to the same set of nuclear targets were innervated from single olivary regions, while those that projected to different sets of nuclear targets were innervated from different subsets of single regions of the inferior olive. The results suggest that the olivary bands of the cerebellar cortex project to the cerebellar nuclei with a diverging pattern that is organized in both the mediolateral and the anteroposterior axes.
Dopamine D2receptors regulate tyrosine hydroxylase activity and phosphorylation at Ser40 in rat striatum
Authors: Lindgren Niklas , Xu Zhi‐Qing David , Herrera‐Marschitz Mario , Haycock John , Hökfelt Tomas , Fisone Gilberto 
Published: March 2003

AbstractIn the striatum, dopamine release is inhibited by activation of dopamine D2autoreceptors. Changes in dopamine release have been attributed to changes in the synthesis of dopamine, which is regulated via phosphorylation of tyrosine hydroxlase (TH), the rate‐limiting enzyme in the synthesis of catecholamines. Here, we have studied the involvement of dopamine D2receptors in the regulation of TH phosphorylation at distinct seryl residues, using phosphorylation site‐specific antibodies and a preparation of rat striatal slices. The D2receptor agonist, quinpirole, reduced basal TH phosphorylation at Ser40 but not at Ser19 or Ser31. Quinpirole was also able to reduce the increase in Ser40 phosphorylation caused by forskolin, an activator of adenylyl cyclase, without affecting the increase in Ser19 phosphorylation produced by the glutamate receptor agonist,N‐methyl‐d‐aspartate (NMDA). In addition, the dopamine D2receptor agonist reduced both basal and forskolin‐stimulated activity of TH, measured as 3,4‐dihydroxyphenylalanine (DOPA) accumulation. Quinpirole decreased phosphorylation of Ser40 induced by okadaic acid, an inhibitor of protein phoshatase 1 and 2A and Ro‐20‐1724, a phosphodiesterase inhibitor. In contrast, quinpirole did not affect the increase in Ser40 phosphorylation caused by the cAMP analogue, 8‐Br‐cAMP. These data indicate that, in the striatum, activation of dopamine D2receptors results in selective inhibition of TH phosphorylation at Ser40 via reduction of the activity of adenylyl cyclase. They also provide a molecular mechanism accounting for the ability of dopamine D2autoreceptors to inhibit dopamine synthesis and release from nigrostriatal nerve terminals.
RGS9 proteins facilitate acute tolerance to mu‐opioid effects
Authors: Garzón Javier , Rodríguez‐Díaz Marta , López‐Fando Almudena , Sánchez‐Blázquez Pilar 
Published: March 2003

AbstractThis paper reports that regulators of G‐protein signalling (RGS) proteins modulate the timing and amplitude of opioid signals by a push–pull mechanism. This is achieved without noticeable changes in the binding properties of opioids, e.g. β‐endorphin to mu‐opioid receptors. The expression of RGS proteins was reduced by blocking their mRNA with antisense oligodeoxynucleotides (ODN). Knock down of RGS2 or RGS3 diminished morphine and β‐endorphin analgesia, whereas that of RGS9 or RGS12 enhanced this activity. In mice with impaired RGS9, but not impaired RGS2, the potency and, in particular, the duration of opioid antinociception increased. Further, the animals did not exhibit acute tolerance generated by a single and efficacious dose of morphine, nor did they develop tolerance after a daily i.c.v. injection of the opioid for 4 days. In a model of sustained morphine treatment, the impairment of RGS9 proteins facilitated increases in the response to the delivered opioid. This was only effective for 2–3 h after the subcutaneous implantation of an oily morphine pellet; later, tolerance developed. To reduce the impact of the chronic morphine acting on opioid receptors, other RGS proteins presumably substitute the GTPase‐activating function of RGS9 on morphine‐activated Gα‐GTP subunits. The desensitization of mu‐opioid receptors appears to be a cell membrane‐limited process facilitated by RGS9′s sequestering of agonist‐segregated Gα subunits.
Gating of vagal inputs by sciatic afferents in nonspinally projecting neurons in the rat rostral ventrolateral medulla oblongata
Authors: Zagon A. , Hughes D. I. 
Published: March 2003

AbstractIntegration and coordination of somato‐visceral sensory information is crucial to achieve adaptive behavioural responses. We have recently shown that sensory vagal and somato‐sensory (sciatic nerve) inputs converge in neurons of the rostral ventrolateral medulla oblongata, which was implicated in adjusting visceral activities to changing somatic performances. In the present study, the neuronal mechanism of interaction between sciatic and vagal sensory inputs was examined in the rostral ventrolateral medulla oblongata using in vivo intracellular recording and labelling. Conditioning stimulation of the contralateral sciatic nerve (2 V) led to a time‐dependent inhibition of responses to vagal stimulation (100 µA) in each RVLM neuron that received convergent sciatic and vagal sensory inputs (n = 50). None of these neurons had direct spinal projections, and only 8% of them exhibited a visible response to stimulation of the aortic depressor nerve. A significant attenuation of the amplitude of vagal test responses was present for up to 800 ms of conditioning delay, although the duration of this sciatico‐vagal inhibition was greatly dependent on the intensity of both stimuli. The electrophysiological data indicated that sciatico‐vagal inhibition is mediated presynaptically, via activation of GABAB receptors. Morphological evidence of axo‐axonic interactions that may underlie sciatico‐vagal inhibition was subsequently found in the electron microscope. It is suggested that during movements of the hindleg, activation of sciatic sensory fibres leads to re‐patterning of neuronal activity in RVLM neurons via inhibition of visceral sensory inputs. Sciatico‐vagal inhibition is likely to affect the activity of those RVLM neurons that modulate higher neuronal activities via ascending projections.
In vitro effects of acetyl‐dl‐leucine (tanganil®) on central vestibular neurons and vestibulo‐ocular networks of the guinea‐pig
Authors: Vibert Nicolas , Vidal Pierre‐Paul 
Published: March 2003

AbstractFor 40 years, the amino acid acetyl‐dl‐leucine (or isoleucine/Tanganil®) has been used in clinical practice to reduce the imbalance and autonomic signs associated with acute vertigo crises. In animal models, acetyl‐dl‐leucine was shown to accelerate vestibular compensation following unilateral labyrinthectomy, while having only minor effects on normal vestibular function. However, the underlying mechanisms are unknown. In this study, the effect of acetyl‐dl‐leucine on the activity of central vestibular neurons of the medial vestibular nucleus (MVN) and/or the overall activity of vestibular‐related networks was electrophysiologically measured in brainstem slices and in the isolated, in vitro whole brain (IWB) of guinea‐pig. Only moderate effects were obtained in normal animals, where both excitatory and inhibitory actions of acetyl‐dl‐leucine were obtained. However, intracellular recordings from MVN neurons revealed that the nature of the response depended on the resting membrane potential. The neurons excited by acetyl‐dl‐leucine were significantly hyperpolarized compared to nonsensitive cells, whereas the neurons inhibited by this compound tended to display higher than normal membrane potentials. In accordance with these data, acetyl‐dl‐leucine reduced the prominent asymmetry characterizing the vestibular‐related networks of IWBs taken from previously labyrinthectomized animals, by decreasing the activity of the abnormally depolarized neurons on the hyperactive side. Altogether, our results suggest that acetyl‐dl‐leucine might act mainly on abnormally hyperpolarized and/or depolarized MVN neurons, by bringing back their membrane potential towards a mean value of −65 to −60 mV. Since in animal models, acute vestibular disorders are associated with asymmetrical spontaneous activities of MVN neurons, this study suggests how acetyl‐dl‐leucine may reduce acute, vestibular‐related imbalances in humans.
Novelty‐evoked elevations of nucleus accumbens dopamine: dependence on impulse flow from the ventral subiculum and glutamatergic neurotransmission in the ventral tegmental area
Authors: Legault Mark , Wise Roy A. 
Published: March 2003

AbstractIn vivomicrodialysis in freely moving rats was used to monitor novelty‐evoked elevations in extracellular dopamine in the nucleus accumbens septi (NAS) and to examine the role of the ventral subiculum of the hippocampus and glutamatergic transmission in the ventral tegmental area (VTA) on these elevations. Exposure to novel stimuli evoked investigatory activity and increased nucleus accumbens dopamine. Unilateral injections of the sodium channel blocker tetrodotoxin (0.16 ng/0.5 µL) into the ventral subiculum ipsilateral to the dialysed NAS abolished novelty‐evoked elevations in dopamine. Injections of tetrodotoxin into the contralateral VS did not prevent novelty‐evoked elevations in nucleus accumbens dopamine. Unilateral perfusion (via microdialysis) of the ionotropic glutamate receptor antagonists kynurenic acid (1 mm) into the ipsilateral but not the contralateral VTA blocked novelty‐evoked elevations in nucleus accumbens dopamine. Neither unilateral injections of tetrodotoxin nor unilateral perfusion of kynurenic acid disrupted investigatory behaviour. These data indicate that phasic elevations in nucleus accumbens dopamine evoked by exposure to unconditioned novel stimuli are dependent on impulse flow from the hippocampus and glutamatergic transmission in the VTA.
Immunocytochemical identification and analysis of the diffuse bipolar cell type DB6 in macaque monkey retina
Authors: Chan Tricia L. , Martin Paul R. , Grünert Ulrike 
Published: March 2003

AbstractThe distribution and morphology of CD15‐immunoreactive bipolar cells were studied in the retina of macaque monkey. Labelled cells have a large dendritic tree contacting several cones and a narrowly stratified axon terminal that ends deep in the inner plexiform layer, close to the ganglion cell layer. The morphology of the labelled cells corresponds to that of the diffuse bipolar cell type named DB6 by Boycott & Wässle (1991; Eur. J. Neurosci., 3,1069). We conclude that CD15 is a marker for DB6 bipolar cells, enabling the quantitative analysis of the distribution and connectivity of this diffuse bipolar cell type.
Defining the role of Drosophila lateral neurons in the control of circadian rhythms in motor activity and eclosion by targeted genetic ablation and PERIOD protein overexpression
Authors: Blanchardon Eric , Grima Brigitte , Klarsfeld André , Chélot Elisabeth , Hardin Paul E. , Préat Thomas , Rouyer François 
Published: March 2003

AbstractThe ventral lateral neurons (LNvs) of the Drosophila brain that express the period (per) and pigment dispersing factor (pdf) genes play a major role in the control of circadian activity rhythms. A new P‐gal4 enhancer trap line is described that is mostly expressed in the LNvs This P‐gal4 line was used to ablate the LNvs by using the pro‐apoptosis gene bax, to stop PER protein oscillations by overexpressing per and to block synaptic transmission with the tetanus toxin light chain (TeTxLC). Genetic ablation of these clock cells leads to the loss of robust 24‐h activity rhythms and reveals a phase advance in light–dark conditions as well as a weak short‐period rhythm in constant darkness. This behavioural phenotype is similar to that described for disconnected1 (disco1) mutants, in which we show that the majority of the individuals have a reduced number of dorsally projecting lateral neurons which, however, fail to express PER. In both LNv‐ablated and disco1 flies, PER cycles in the so‐called dorsal neurons (DNs) of the superior protocerebrum, suggesting that the weak short‐period rhythm could stem from these PDF‐negative cells. The overexpression of per in LNs suppresses PER protein oscillations and leads to the disruption of both activity and eclosion rhythms, indicating that PER cycling in these cells is required for both of these rhythmic behaviours. Interestingly, flies overexpressing PER in the LNs do not show any weak short‐period rhythms, although PER cycles in at least a fraction of the DNs, suggesting a dominant role of the LNs on the behavioural rhythms. Expression of TeTxLC in the LNvs does not impair activity rhythms, which indicates that the PDF‐expressing neurons do not use synaptobrevin‐dependent transmission to control these rhythms.
Developmental pattern of expression of the alpha chemokine stromal cell‐derived factor 1 in the rat central nervous system
Authors: Tham To Nam , Lazarini Françoise , Franceschini Isabelle Amiko , Lachapelle François , Amara Ali , Dubois‐Dalcq Monique 
Published: March 2003

AbstractStromal cell‐derived factor 1 (SDF‐1) is an alpha‐chemokine that stimulates migration of haematopoietic progenitor cells and development of the immune system. SDF‐1 is also abundantly and selectively expressed in the developing and mature CNS, as we show here. At embryonic day 15, SDF‐1 transcripts were detected in the germinal periventricular zone and in the deep layer of the forming cerebral cortex. At birth, granule cells in the cerebellum and glial cells of the olfactory bulb outer layer showed an SDF‐1 in situ hybridization signal that decreased progressively within the next 2 weeks. In other regions such as cortex, thalamus and hippocampus, SDF‐1 transcripts detected at birth progressively increased in abundance during the postnatal period. SDF‐1 protein was identified by immunoblot and/or immunocytochemistry in most brain regions where these transcripts were detected. SDF‐1 was selectively localized in some thalamic nuclei and neurons of the fifth cortical layer as well as in pontine and brainstem nuclei which relay the nociceptive response. The presence of SDF‐1 transcripts in cerebellar granule cells was correlated with their migration from the external to the inner granular layers with disappearance of the signal when migration was completed. In contrast, SDF1 mRNA signal increased during formation of the hippocampal dentate gyrus and stayed high in this region throughout life. The selective and regulated expression of SDF‐1 in these regions suggests a role in precursor migration, neurogenesis and, possibly, synaptogenesis. Thus this alpha chemokine may be as essential to nervous system function as it is to the immune system.
Neurochemical and electrophysiological evidence that 5‐HT4 receptors exert a state‐dependent facilitatory control in vivo on nigrostriatal, but not mesoaccumbal, dopaminergic function
Authors: Lucas Guillaume , Di Matteo Vincenzo , De Deurwaerdère Philippe , Porras Grégory , Martín‐Ruiz Raúl , Artigas Francesc , Esposito Ennio , Spampinato Umberto 
Published: March 2003

AbstractIn this study we investigated, using in vivo microdialysis and single unit recordings, the role of serotonin4 (5‐HT4) receptors in the control of nigrostriatal and mesoaccumbal dopaminergic (DA) pathway activity. In freely moving rats, the 5‐HT4 antagonist GR 125487 (1 mg/kg, i.p.), without effect on its own, significantly reduced the enhancement of striatal DA outflow induced by 0.01 (−35%) and 0.1 (−66%), but not 1 mg/kg, s.c. haloperidol (HAL). Intrastriatal infusion of GR 125487 (1 µm) had no influence on basal DA outflow, but attenuated (−49%) the effect of 0.01 mg/kg HAL. Systemic administration of GR 125487 modified neither basal nor 0.01 mg/kg HAL‐stimulated accumbal DA outflow. In halothane‐anaesthetized rats, 1 or 10 mg/kg GR 125487, without effect by itself, failed to modify the changes in accumbal and striatal DA outflow elicited by electrical stimulation (300 µA, 1 ms, 20 Hz, 15 min) of the dorsal raphe nucleus. Finally, GR 125487 (444 µg/kg, i.v.), whilst not affecting basal firing of DA neurons within either the substantia nigra or the ventral tegmental area, reduced HAL‐stimulated (1–300 µg/kg, i.v.) impulse flow of nigrostriatal DA neurons only. These results indicate that 5‐HT4 receptors exert a facilitatory control on both striatal DA release and nigral DA neuron impulse flow only when nigrostriatal DA transmission is under activated conditions. Furthermore, they indicate that the striatum constitutes a major site for the expression of the control exerted by 5‐HT4 receptors on DA release. In contrast, 5‐HT4 receptors have no influence on mesoaccumbal DA activity in either basal or activated conditions.
Electrophysiological analysis of suprachiasmatic nucleus projections to the ventrolateral preoptic area in the rat
Authors: Sun X. , Whitefield S. , Rusak B. , Semba K. 
Published: March 2003

AbstractThe circadian pacemaker housed in the suprachiasmatic nucleus (SCN) synchronizes daily sleep–wake cycles, presumably by modulating the sleep–wake regulatory system, including ventrolateral preoptic area (VLPO) neurons. We used whole‐cell patch‐clamp recording to study the projections from the SCN to the VLPO in horizontal slices of rat hypothalamus. Single‐pulse stimulation of the SCN region elicited postsynaptic currents (PSCs) in 20 of 66 neurons (30%) recorded within the VLPO region as verified by intracellular biocytin labelling. At a holding potential of −60 mV, the evoked PSCs had an amplitude of 17.6 ± 3.2 pA (SEM) and a latency of 6.3 ± 0.5 ms (n = 10). There was a trend for simple excitatory postsynaptic currents (EPSCs) to be evoked in the VLPO cluster, simple inhibitory postsynaptic currents (IPSCs) in the extended VLPO, and a combination of EPSCs and IPSCs in both regions. IPSCs were blocked reversibly by bicuculline (10 µm, n = 11). In both the presence and absence of bicuculline, EPSCs had fast and slow components that were blocked by 6,7‐dinitroquinoxaline‐2,3‐dione (DNQX; 10 µm; n = 7), and (±)3‐(2‐carboxypiperazin‐4‐yl)‐propyl‐1‐phosphonic acid (CPP; 10 µm, n = 6), respectively. Reversal potentials for the evoked IPSCs and EPSCs were consistent with mediation via GABAA and ionotropic glutamate receptors, respectively. These results suggest that the SCN region provides both inhibitory and excitatory inputs to single VLPO neurons, which are mediated, respectively, by GABAA receptors and by both non‐NMDA and NMDA glutamate receptors. These projections may play important roles in conveying circadian input to systems in the preoptic area that regulate sleep and waking.
Processing of facial emotional expression: spatio‐temporal data as assessed by scalp event‐related potentials
Authors: Krolak‐Salmon P. , Fischer C. , Vighetto A. , Mauguière F. 
Published: March 2003

AbstractEvent‐related potentials (ERPs) were recorded in 10 adult volunteers, who were asked to view pictures of faces with different emotional expressions, i.e. fear, happiness, disgust, surprise and neutral expression [Ekman, P. & Friesen, W.V. (1975). Pictures of Facial Affect. Consulting Psychologist Press, Palo Alto, CA]. ERPs were recorded during two different tasks with the same stimuli. Firstly, subjects were instructed to pay attention to the gender of the faces by counting males or females. Secondly, they had to focus on facial expressions by counting faces who looked surprised. The classical scalp ‘face‐related potentials’, i.e. a vertex‐positive potential and a bilateral temporal negativity, were recorded 150 ms after the stimulus onset. Significant differences were found, firstly between late‐latency ERPs to emotional faces and to neutral faces, between 250 and 550 ms of latency and, secondly, among the ERPs to the different facial expressions between 550 and 750 ms of latency. These differences appeared only during the expression discrimination task, not during the gender discrimination task. Topographic maps of these differences showed a specific right temporal activity related to each emotional expression, some particularities being observed for each expression. This study provides new data concerning the spatio‐temporal features of facial expression processing, particularly a late‐latency activity related to specific attention to facial expressions.
Intrinsic connectivity of human auditory areas: a tracing study with DiI
Authors: Tardif Eric , Clarke Stephanie 
Published: March 2003

AbstractThe human supratemporal plane contains the primary as well as several other auditory areas. We have investigated the intrinsic connectivity of these areas by means of antero‐ and retrograde labelling with the carbocyanin dye DiI (1,1′‐dioctadecyl‐3,3,3′,3′‐tetramethylindocarbocyanine perchlorate). A total of 30 injections was placed in both hemispheres of four freshly fixed postmortem brains. Labelled neurons and axons were found in cortex around the injection. The retrograde labelling varied from faint to Golgi‐like; most of the retrograde labelled neurons were layers II–III pyramids and only a few were nonpyramidal neurons. Labelled axons were dense in all layers near the injection site, while they became relatively rare in layer IV further away. The tangential spread of labelling differed among auditory areas. On Heschl's gyrus (corresponding to the primary auditory cortex and cytoarchitectonic areas TD and part of TB) intrinsic connectivity involved a relatively narrow part of cortex. They spread over larger parts of cortex in plana polare and temporale (areas TG, TA and the remaining part of TB). A number of injections also produced anisotropic labelling patterns. These results reveal differences in intrinsic connectivity between auditory areas. They suggest that intrinsic connections within the primary auditory area, area TD and part of TB that is on Heschl's gyrus, involve mainly nearby units or modules, probably with similar coding properties, whereas in surrounding areas, connections spread over more distant units and may play an important role in the integration of different auditory features.