bluuebunny/crossref_metadata_2025_split huggingface dataset:
Connections of the Lateral Reticular Nucleus to the Lateral Vestibular Nucleus in the Rat. An Anterograde Tracing Study with Phaseolus vulgaris Leucoagglutinin
Authors: Ruigrok T. J. H. , Cella F. , Voogd J. 
Published: April 2006

AbstractEfferent projections from the lateral reticular nucleus in the rat were investigated with anterograde transport of Phaseolus vulgaris leucoagglutinin. Besides the well known mossy fibre connections to the cerebellar cortex and collaterals to the cerebellar nuclei, a substantial bilateral projection to the lateral vestibular nucleus was found. Terminal arborizations found within this nucleus appeared to detach from the reticulocerebellar fibres in the cerebellar white matter and enter the lateral vestibular nucleus from dorsally. This projection may have functional relevance for the control, by ascending spinal pathways, of the descending lateral vestibulospinal tract.
Differences in the Temporal Properties of Human Longwave‐ and Middlewave‐sensitive Cones
Authors: Whitmore A. V. , Bowmaker J. K. 
Published: April 2006

AbstractIn recent years a number of electrophysiological and psychophysical observations have suggested that the temporal properties of the human longwave‐ and middlewave‐sensitive cones might be different. However, until now the issue has remained unresolved, despite its obvious importance. We have succeeded in probing, electrophysiologically, the temporal properties of the two classes, under a range of adapting conditions, in a normal human observer. Here we present evidence that the temporal properties of these cone types are indeed different and that this difference is constant irrespective of the state of light adaptation, suggesting that light adaptation has little effect on the kinetics of transduction in human cones.
NMDA‐Dependent GABAA‐Mediated Polysynaptic Potentials in the Neonatal Rat Hippocampal CA3 Region
Authors: McLean H. A. , Rovira C. , Ben‐Ari Y. , Gaiarsa J.‐L. 
Published: April 2006

AbstractEvoked inhibitory postsynaptic potentials (IPSPs) were studied in CA3 hippocampal neurons from brain slice preparations of rats ranging from 5 to 18 days of age (P5–18) using intracellular recording techniques. With KMeSO4‐filled electrodes the evoked inhibitory response consisted of fast and slow IPSPs mediated by GABAA and GABAB receptors respectively. In recordings obtained with electrodes filled with 2‐(triethylamino)‐N‐(2,6‐dimethylphenyl) acetamide and KMeSO4, electrical stimulation evoked monophasic IPSPs in mature slices (P10–18) and biphasic IPSPs with an early and a late phase in neonatal slices (P4–7). In neonates both the early and late phases of the IPSP were mediated by GABAA receptors. Pharmacological investigation revealed that the early phase arose from both direct and feedforward activation of GABAergic interneurons involving non‐NMDA receptors, while the late phase resulted from polysynaptic activation of GABAergic interneurons mediated by NMDA receptors.
Involvement of Substance P in Ultraviolet Irradiation‐induced Inflammation in Rat Skin
Authors: Eschenfelder Christoph C. , Benrath Justus , Zimmermann Manfred , Gillardon Frank 
Published: April 2006

AbstractThe possible involvement of substance P released from primary afferents in rat skin was investigated in cutaneous inflammation following ultraviolet (UV) irradiation. Recordings from c‐fibres innervating the UV‐exposed hindpaw skin showed long‐lasting low‐frequency (0.8–1.25 Hz) spontaneous activity. Spontaneously active c‐fibres increased to constitute 35.3% of the total population 72 h after UV exposure. Immunohisto‐chemical analysis of substance P‐containing nerve fibres in hindpaw skin revealed a significant increase in substance P immunoreactivity 24 h after UV irradiation. Average length of substance P‐immunolabelled nerve fibres was about two times higher in UV‐exposed compared to control skin. UV‐induced oedema was investigated in rat ears using an ear‐swelling test. Intradermal injection of either peptide (Spantide) or non‐peptide (CP‐96,345) substance P antagonists and epicutaneous application of CP‐96,345 reduced UV‐induced oedema significantly in the late phase of sunburn (>12 h after UV exposure). The UV‐induced increase in skin blood flow was investigated in hindpaw skin up to 72 h by the laser Doppler technique. Epicutaneous application of CP‐96,345 reduced erythema significantly between 12 and 72 h after UV exposure. Thus, our findings suggest the involvement of neurogenic substance P as a proinflammatory mediator in the late phase of UV‐induced cutaneous inflammation in rats.
The Entorhinal Cortex Entrains Fast CA1 Hippocampal Oscillations in the Anaesthetized Guinea‐pig: Role of the Monosynaptic Component of the Perforant Path
Authors: Charpak S. , Paré D. , Llinás R. 
Published: April 2006

AbstractEntorhinal inputs reach the hippocampal CA1 field through a trisynaptic circuit involving dentate granule cells and CA3 pyramidal neurons, as well as through a monosynaptic path ending on the distal apical dendrites of CA1 pyramidal cells. The influence of monosynaptic entorhinal inputs onto CA1 operations is poorly understood. In this study, we characterized the involvement of the monosynaptic pathway in the generation of the fast CA1 oscillation bursts (30–60 Hz) that occur in the dorsal hippocampus of anaesthetized guinea‐pigs after partial cortex removal. Using multiple‐site extracellular and intracellular recording, we found that in this particular preparation, devoid of theta rhythm, fast oscillations are temporally coherent over a large portion of the CA1 region along the hippocampal septotemporal axis. Current source density analysis revealed that fast CA1 oscillations involve two dipoles reflecting synchronous synaptic activities in the stratum lacunosum‐moleculare of the hippocampus proper and in the stratum moleculare of the dentate gyrus. These layers constitute the two major termination zones of entorhinal afferents, suggesting that the entorhinal cortex entrains fast CA1 oscillations. This hypothesis was corroborated by the concomitant occurrence of fast oscillation bursts in the entorhinal cortex and CA1 region. Furthermore, fast CA1 oscillations were abolished by lidocaine or tetrodotoxin injections in the entorhinal cortex. Finally, acute interruption of the hippocampal trisynaptic loop did not affect the stratum lacunosum‐moleculare dipole recorded extracellularly, but also intracellularly, as high‐frequency postsynaptic potentials in CA1 pyramidal cells. These results indicate that the monosynaptic pathway is involved in the genesis of fast CA1 oscillations.
Comparison of Frequency‐specific c‐Fos Expression and Fluoro‐2‐deoxyglucose Uptake in Auditory Cortex of Gerbils (Meriones unguiculatus)
Authors: Zuschratter Werner , Gass Peter , Herdegen Thomas , Scheich Henning 
Published: April 2006

AbstractInduction of c‐Fos in the auditory cortex of gerbils was investigated immunocytochemically 1 h after single, triple or 1 h continuous stimulation with a series of narrow band frequency‐modulated tone bursts. With single stimulation c‐Fos immunoreactive neurons were chiefly found in the primary auditory field (AI), where they formed a narrow frequency‐specific column across layers II‐VI. Side‐band‐like patterns adjacent to this column appeared characteristically with triple stimulation. Immunoreactive cell density in the anterior auditory field and the caudal fields was sparse and location not frequency specific with single or triple stimulation. Spatial comparisons of c‐Fos immunoreactive neuron density with 2‐deoxy‐2‐fluoro‐D‐glucose (FDG) autoradiography in the same animals after 1 h of stimulation revealed spreading of c‐Fos expression in neurons across the tonotopic maps of the Al and in the rostral and caudal fields of the auditory cortex. The pattern of the highest density of c‐Fos labelled cells in the Al still matched the peak labelling of FDG autoradiographs. The results show that the postsynaptic marker c‐Fos reflects the frequency representation in the Al with single or triple stimulation yet with a higher spatial resolution than the deoxyglucose technique. Longer stimulation causes non‐tonotopic intracortical spreading of the c‐Fos‐inducing message, a phenomenon potentially reflecting the effects of cooperativity in the maps.
Simultaneous Expression of Long‐term Depression of NMDA and Long‐term Potentiation of AMPA Receptor‐mediated Synaptic Responses in the CA1 Area of the Kainic Acid‐lesioned Hippocampus
Authors: Bernard Christophe L. , Wheal Howard V. 
Published: April 2006

AbstractThis study investigates the plasticity of the excitatory synapses in an experimental model of epilepsy, the kainic acid‐lesioned rat hippocampus. Stimulation of afferents in the CA1 area of lesioned hippocampi produced an epileptiform burst of action potentials, with an underlying synaptic potential composed of mixed α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionate (AMPA; 80%) and N‐methyl‐D‐aspartate (NMDA; 20%) receptor‐mediated components. Tetanic stimulation yielded a long‐term potentiation (LTP) of the mixed AMPA/NMDA receptor‐mediated population excitatory postsynaptic potentials. However, the same type of tetanus resulted in a long‐term depression (LTD) of pharmacologically isolated NMDA receptor‐mediated responses. This LTD occurred independently of the antagonism of AMPA receptors. This suggests that tetanic stimulation produced LTP of AMPA and LTD of NMDA receptor‐mediated responses simultaneously. Finally, both LTP and LTD were shown to be NMDA dependent. This property has profound functional implications for the control of excitatory networks in temporal lobe epilepsy. This work was supported by the Wellcome Trust and the Fondation Simone et Cino Del Duca.
β‐Adrenergic Receptor Activation Promotes Process Outgrowth in an Embryonic Rat Basal Forebrain Cell Line and in Primary Neurons
Authors: Kwon John H. , Eves Eva M. , Farrell Stephen , Segovia Jose , Tobin Allan J. , Wainer Bruce H. , Downen Martha 
Published: April 2006

AbstractA clonal cell line, AS583‐8.E4.22, from the embryonic day 15 rat basal forebrain was established using retrovirus‐mediated transduction of a temperature‐sensitive mutant of the simian virus 40 (SV40) large tumour antigen. The cell line expresses cytoskeletal and neurotransmitter features indicative of neuronal commitment. In response to agents that increase intracellular CAMP, including forskolin and catecholamines, the cell line exhibits rapid process outgrowth and growth cone formation that does not require new gene expression or protein synthesis. The neurite outgrowth induced by catecholamines is mediated by β2‐adrenergic receptors and is characterized by a rapid, reversible redistribution of filamentous actin. Neurons from primary cultures of embryonic day 15 basal forebrain were also found to respond to β‐adrenergic receptor agonists by enhancing growth cone formation. These results suggest that catecholamines provide cues that induce cytoskeletal rearrangements leading to neuronal process outgrowth and growth cone formation in the developing basal forebrain and possibly other neuronal progenitor cell populations. The neuronal basal forebrain cell line provides an ideal model to study the signalling mechanisms underlying the catecholamine‐induced process outgrowth.
Pain Perception under Chronic High‐altitude Hypoxia
Authors: Noël‐Jorand M. C. , Bragard D. , Plaghki L. 
Published: April 2006

AbstractFollowing studies of respiratory sensory functions during high‐altitude adaptation, pain perception investigations were carried out on European lowlanders during an expedition on the Bhrikuti peak, Himalaya (first ascent). Perception thresholds and discrimination performances of electrical stimuli applied to the skin were determined with a constant stimulus method. Additionally, Clark's Situational Pain Questionnaire was used to measure discriminability and response bias of the subjects' reports of pain. The tests were performed in the field under normoxic conditions, before and after ascent, and under hypoxic conditions at altitudes of 3500 and 5600 m. The tests were also performed in a control group under normoxic conditions and similar ambient temperatures. Under normoxic conditions, the expedition group differed from the control group and demonstrated a more stoic attitude and a lower pain threshold. At high altitudes, pain thresholds decreased through improved sensory discrimination performances. Hypoxia is supposed to be the main cause of this sensory adaptive reaction to altitude as psychological attitude remained unchanged and a decrease in ambient temperature was without effect on pain perception in the control group. Increased discrimination in pain perception may be a component of a general improvement in sensory processing during the early stages of altitude acclimatization.
The Projections of the Lateral Reticular Nucleus to the Deep Cerebellar Nuclei. An Experimental Analysis in the Rat
Authors: Parenti Rosalba , Cicirata Federico , Pantò Maria Rosita , Serapide Maria Francesca 
Published: April 2006

AbstractThe projections of the lateral reticular nucleus (LRN) to the cerebellar nuclei were studied using the retrograde axonal transport of tetramethyl rhodamine dextran amine (10% solution in 0.01 M neutral phosphate buffer) in 19 adult Wistar strain rats. The cerebellar nuclei receive topographically organized projections from the LRN. The projections are bilateral with an ipsilateral predominance and they are symmetrical. The contralateral component is progressively larger for projections to the nuclei interpositalis, to the nucleus lateralis and to the nucleus medialis. The projections to the various cerebellar nuclei arise from rostrocaudally oriented columns of neurons located in different (partly overlapping) areas of the magnocellular division of the LRN. The nucleus lateralis receives terminals from the dorsomedial area (mainly from the rostral level of the LRN), the nuclei interpositalis from the dorsolateral area (mainly from the central level) and the nucleus medialis from the intermedioventral area (mainly from the caudal level). Afferent fibres from the small subtrigeminal division were traced to the three cerebellar nuclei and from the parvocellular division to the nuclei interpositalis and medialis. The density of the projections from the LRN to the nuclei interpositalis increases progressively with the shift of the terminal field from the rostrolateral to the caudomedial part of the nucleus. The projections to the nucleus lateralis reach principally the dorsolateral hump, whereas only a few neurons project to the other divisions (parvo‐ and magnocellular). The projections to the various regions of the nucleus medialis show different densities. The highest density was found for projections to the caudal part, in particular to the dorsolateral protuberance and to the ventrolateral area of the middle division. Conversely, a low density of projections was found for the other areas of the middle division. The regions of the magnocellular division of the LRN which project to the nuclei lateralis (and are thus related to the cerebral cortex), interpositalis (related to the red nucleus) and medialis (related to the spinal cord) also receive afferent terminals from the cerebral cortex, the red nucleus and the spinal cord respectively, in addition to various afferent inputs. Thus, each of these areas is apparently concerned with integrating some spinal and supraspinal information in reverberating circuits.
Pre‐ and Post‐synaptic Actions of 5‐Hydroxytryptamine in the Rat Lumbar Dorsal Horn In Vitro: Implications for Somatosensory Transmission
Authors: Lopez‐Garcia J. A. , King A. E. 
Published: April 2006

AbstractSince the relative contribution of pre‐ versus post‐synaptic actions of 5‐hydroxytryptamine (5‐HT) to modulation of somatosensory processing in the dorsal horn is not known, recordings fro m primary afferents and dorsal horn neurons from in vitro rat spinal cord were used to address this issue. 5‐HT produced a depression of spontaneous dorsal root potentials and a slow primary afferent depolarization (PAD): the PAD versus 5‐HT concentration‐response curve was bell shaped (maximum at 5 μM; 250±C 41.5 μV). In 28/40 dorsal horn neurons, 5‐HT elicited a slow depolarization not clearly associated with a specific input resistance change. Excitatory synaptic transmission from primary afferents to dorsal horn neurons was depressed by 5‐HT in 40/45 neurons. 5‐HT ≥ 5 μM significantly (P≤ 0.05) decreased the amplitude, shortened the total duration and half‐decay time of the excitatory post‐synaptic potential (EPSP). A dominant effect of 5‐HT on longer latency EPSP components was evident. There was no direct relationship between the magnitude of PAD and the reduction of the EPSP by 5‐HT. 5‐Carboxamidotryptamine, an agonist for 5‐HT1 receptors, mimicked the depression of neurotransmission in the dorsal horn without producing PAD. A sample of dorsal horn neurons (n= 8) was injected with biocytin and their morphology described. All had somata within laminae III‐VI. In five of these neurons 5‐HT depressed the EPSP but in one interneuron‐like and one unclassed neuron the EPSP was potentiated. These data suggest that whilst depression of synaptic transmission is the predominant effect of 5‐HT in the deep dorsal horn, this is not easily related to PAD or cellular actions of 5‐HT on dorsal horn neurons.
Improved Motor Function of Denervated Rat Hindlimb Muscles Induced by Embryonic Spinal Cord Grafts
Authors: Nógrádi Antal , Vrbová Gerta 
Published: April 2006

AbstractLoss of motoneurons results in a decrease in force production by skeletal muscles and paralysis. Although it has been shown that missing motoneurons of rats can be replaced by embryonic homotopic neurons, attempts to guide their axons to their target muscles that have lost their innervation have been unsuccessful. In this study attempts were made to guide axons from grafted embryonic motoneurons to their target via a reimplanted ventral root. Adult hosts that received an embryonic graft prelabelled with 5‐bromo‐2′‐deoxyuridine had their L4 ventral root avulsed and reimplanted into the spinal cord. Three to six months later, neurons that had their axons in the L4 ventral ramus were retrogradely labelled with fast blue and diamidino yellow. In five animals that had received an embryonic graft 116 ± 16 cells were retrogradely labelled, and of these at least 15% were of graft origin, since they were positive for 5‐bromo‐2′‐deoxyuridine. In five animals that had their L4 ventral root reimplanted but did not receive a graft, only 12 ± 1.3 cells were retrogradely labelled. However, meaningful functional recovery could be achieved only if the regenerating axons of embryonic motoneurons found in the L4 ventral ramus were able to reverse the loss of force of muscles that had lost their innervation. This study shows that axons of embryonic motoneurons grafted into an adult rat spinal cord, as well as some axons of host origin, can be guided to denervated hindlimb muscles via reimplanted lumbar ventral roots. In normal rats ∼30 motor axons innervated the extensor digitorurn longus and 60 innervated the tibialis anterior via the L4 ventral root. In rats that did not receive a graft only 3.7 ± 1.2 axons reached the extensor digitorum longus and 3.5 ± 0.4 reached the tibialis anterior muscle via the implanted L4 ventral root. In animals that had an embryonic graft, 7.6 ± 0.5 axons innervated the extensor digitorum longus and 8.5 ± 0.5 reached the tibialis anterior muscle via the implanted root. In rats without a transplant the maximum tetanic tension elicited by stimulating the implanted L4 root was 16 ± 7 g for the extensor digitorum longus and 53 ± 36 g for the tibialis anterior muscle, whereas the corresponding muscles in animals that had an embryonic graft developed 82 ± 16 and 281 ± 95 g respectively. Thus it appears that the grafted motoneurons contributed to the innervation and functional recovery of the denervated muscles.
Postnatal Changes in the Expression of the trkA High‐affinity NGF Receptor in Primary Sensory Neurons
Authors: Ennett David L. H. , Averill Sharon , Clary Douglas O. , Priestley John V. , McMahon Stephen B. 
Published: April 2006

AbstractIn development ∼70–80% of dorsal root ganglion (DRG) cells are dependent on nerve growth factor (NGF) for their survival, while in the adult only some 40% of DRG cells express the high‐affinity NGF receptor, trkA. This discrepancy suggests that trkA expression, and therefore neurotrophin sensitivity, may alter as the animal matures. We have tested this possibility by counting the number of L4/5 DRG neurons showing immunoreactivity for trkA in rats from the day of birth to postnatal day 14. We also examined changes in p75 and IB4 labelling. On the day of birth, 71% of DRG cells were found to express trkA. However, this percentage gradually fell with age and reached adult levels at postnatal day 14. The expression of p75 did not parallel that of trkA, remaining relatively constant at between 45 and 50% of cells from birth to postnatal day 14. Over the same period there was a marked increase in the proportion of cells which bind the lectin IB4 from 9 (day of birth) to 40% (day 14). Since in the adult the 1B4 population consists of small cells which mostly do not express trkA, this finding suggests that the postnatal down‐regulation of trkA occurs in this population. Consistent with this suggestion are the results of double labelling for trkA and IB4, which confirmed that at times intermediate between birth and postnatal day 14 there was a high degree of coexpression between these markers (which is absent in the adult). This result also suggests that the down‐regulation of trkA is unlikely to be directly responsible for the emerging IB4 binding.
C‐fos Expression During Vocal Mobbing in the New World Monkey Saguinus fuscicollis
Authors: Jürgens U. , Lu C.‐L. , Quondamatteo F. 
Published: April 2006

AbstractIn order to find brain areas involved in the vocal expression of emotion, we compared c‐fos expression in three groups of saddle‐back tamarins (Saguinus fuscicollis). One group, consisting of three animals, was made to utter more than 800 mobbing calls by electrical stimulation of the periaqueductal grey of the midbrain (PAG). A second group, consisting of two animals, was stimulated in the PAG with the same intensity and for the same duration as the first group but at sites that did not produce vocalization. These sites lay somewhat medial to the vocalization‐eliciting sites. A third group, consisting of two animals, was stimulated at vocalization‐eliciting sites in the PAG but with an intensity below vocalization threshold. Fos‐like immunoreactivity that was found in the vocalizing but not in the non‐vocalizing animals was located in the dorsomedial and ventrolateral prefrontal cortex, anterior cingulate cortex, ventrolateral premotor cortex, sensorimotor face cortex, insula, inferior parietal cortex, superior temporal cortex, claustrum, entorhinal and parahippocampal cortex, basal amygdaloid nucleus, anterior and dorsomedial hypothalamus, nucleus reuniens, lateral habenula, Edinger‐Westphal nucleus, ventral and dorsolateral midbrain tegmentum, nucleus cuneiformis, sagulum, pedunculopontine and laterodorsal tegmental nuclei, ventral raphe, periambigual reticular formation and solitary tract nucleus. For some of these structures (e.g. anterior cingulate cortex and periambigual reticular formation), there is evidence also from electrical stimulation, lesioning and single‐unit recording studies that they are involved in vocal control. For other structures (e.g. lateral habenula, Edinger‐Westphal nucleus), the available evidence speaks against such a role. Fos activation in these cases is probably related to non‐vocal reactions accompanying the electrically elicited vocalizations. A third group of structures consists of areas for which a role in vocal control cannot be excluded but for which the present study presents the first evidence for such a role (e.g. claustrum and sagulum). These structures deserve further studies using more specific methods.