bluuebunny/crossref_metadata_2025_split huggingface dataset:
Large Calibre Primary Afferent Neurons Projecting to the Gracile Nucleus Express Neuropeptide Y after Sciatic Nerve Lesions: an Immunohistochemical and In Situ Hybridization Study in Rats
Authors: Zhang Xu , Meister Björn , Elde Robert , Verge Valerie M.K. , Hökfelt Tomas 
Published: April 2006

AbstractUsing immunohistochemistry and in situ hybridization, we studied changes in expression of some neuropeptides in large and medium‐sized neurons in lumbar 4 and 5 rat dorsal root ganglia projecting to the gracile nucleus, in response to peripheral axotomy. Fourteen days after unilateral sciatic nerve transection, many large neurons and some medium‐sized neurons in ipsilateral dorsal root ganglia were strongly neuropeptide Y‐positive. Galanin‐, vasoactive intestinal polypeptide (VIP)‐ and peptide histidine‐isoleucine (PHI)‐like immunoreactivities coexisted with neuropeptide Y‐like immunoreactivity in some of these neurons. After axotomy numerous large and medium‐sized cells contained neuropeptide Y mRNA in the ipsilateral ganglia, whereas no hybridization was seen in the contralateral or control ganglia. Cross‐sectioned, large neuropeptide Y‐positive fibres were observed in a somatotopically appropriate zone within the ipsilateral gracile fasciculus. A dense network of neuropeptide Y‐immunoreactive, large nerve fibres and terminals was seen in the ipsilateral gracile nucleus. A small number of galanin‐ and VIP/PHI‐like immunoreactive nerve fibres and terminals were also observed in adjacent sections. Neuropeptide Y‐like immunoreactivity colocalized with galanin‐ or VIP/PHI‐like immunoreactivity in some nerve fibres. None of these neuropeptide immunoreactivities could be detected in nerve fibres and terminals in the control or contralateral gracile nucleus. These findings suggest that neuropeptides, in addition to their role in small dorsal root ganglion neurons, may have a function in large and medium‐sized dorsal root ganglion neurons projecting to laminae III and IV in the dorsal horn as well as to the gracile nuclei, as a part of their response to peripheral axotomy.
Neurophysiological Evidence for Increased Kappa Opioidergic Control of Spinal Cord Neurons in Rats with Unilateral Inflammation at the Ankle
Authors: Stiller R. U. , Grubb B. D. , Schaible H.‐G. 
Published: April 2006

AbstractThe role of the endogenous kappa opioid system in the control of neuronal activity has been studied in the spinal cord of normal rats and in rats with Freund's adjuvant induced unilateral inflammation of the ankle under barbiturate anaesthesia. During recordings from neurons with ankle input the kappa receptor agonist U50,488H and/or the kappa antagonist nor‐binaltorphamine were administered ionophoreticaliy using multibarrel electrodes. In most neurons tested U50, 488H reduced the responses evoked by pressure applied across the ankle whereas smaller proportions of neurons showed increased activity or were not affected. The kappa opioid antagonist nor‐binaltorphamine affected more neurons in rats with inflammation than in control rats. Ongoing activity was increased in 7 of 19 (37%) neurons in control rats, in 16 of 24 (67%) neurons in the acute phase of inflammation (2 days post inoculation) and in 15 of 23 (65%) neurons in the chronic phase of inflammation (16–20 days post inoculation). During application of nor‐binaltorphamine in control rats, the responses to pressure were increased in 9 cells (36%), reduced in 7 cells (28%) and unaffected in 9 cells (36%). In the acute phase of inflammation significantly more neurons (11 of 15, 73%) showed enhanced responses to pressure during ionophoresis of nor‐binaltorphamine but not in the chronic phase. These results show that spinal cord neurons with ankle input are influenced by the endogenous kappa opioid system particularly under inflammatory conditions. The upregulation of this system under inflammatory conditions may serve to counteract inflammation‐induced hyperexcitability.
Electrical Kindling of the Hippocampus is Associated with Functional Activation of Neuropeptide Y‐containing Neurons
Authors: Rizzi M. , Monno A. , Samanin R. , Sperk G. , Vezzani A. 
Published: April 2006

AbstractThe release of neuropeptide Y (NPY) was measured from hippocampal slices of rats at stage 2 (preconvulsive stage) and stage 5 (full seizure expression) of electrical kindling of the dorsal hippocampus (upper blade of the dentate gyrus). Spontaneous release in naive rats (9.0 ± 0.8 fmol/ml every 10 min) was independent of external Ca2+ but was reduced by 38 ± 3.6% (P < 0.05) during 20 min incubation with 5μM tetrodotoxin. Spontaneous efflux in naive rats did not differ from that in shams (implanted with electrodes but not stimulated) or in rats kindled to stage 2 and stage 5. Twenty‐five, 50 and 100 mM KCl induced a concentration‐dependent release of NPY (P < 0.05 and P < 0.01 at 25 and 50–100 mM respectively) from slices of shams. The effect of 100 mM KCl was reduced by 94 ± 1% (P < 0.01) in the absence of Ca2+. Two days after the last stage 2 stimulation and 1 week after the last stage 5 seizure, NPY release was significantly larger than in shams at all KCl concentrations in the stimulated and contralateral hippocampus (P < 0.05 and P < 0.01). Forty‐eight hours after one single after‐discharge and 1 month after the last stage 5 seizure, 50 mM KCl induced a significantly larger release of NPY in the stimulated and contralateral hippocampus (P < 0.01 and P < 0.05), although the effect was less than during kindling. The tissue concentration of NPY increased significantly in both hippocampi at stage 2 and 1 week after stage 5 (2.6 times on average, P < 0.01) but no significant differences were found 1 month after stage 5. The present results provide the first evidence of enhanced neuronal release of NPY during kindling, suggesting that this neuropeptide may have a potential role in epileptogenesis.
Intracellular Chloride Activity and the Effect of 5‐Hydroxytryptamine on the Chloride Conductance of Leech Retzius Neurons
Authors: Munsch T. , Schlue W.‐R. 
Published: April 2006

AbstractIntracellular Cl‐ activity (aCli) and 5‐hydroxytryptamine (5‐HT)‐induced membrane currents of Retzius neurons in the central nervous system of the medicinal leech were measured using Cl‐ sensitive microelectrodes and a two‐microelectrode voltage‐clamp technique. At the membrane of Retzius neurons Cl‐ ions were not passively distributed. Under different conditions the chloride equilibrium potential (ECl, ‐60.1 mV for isotonic saline and ‐57.8 mV for a hypertonic saline) was negative with respect to the membrane potential (Em‐55 ± 3.8 and ‐47 ± 3.4 mV respectively). The endogenous neurohormone 5‐HT always polarized the membrane of Retzius neurons in the direction of ECl. When voltage‐clamping the membrane of Retzius neurons near the resting potential both in situ and in primary culture, application of 5‐HT produced an outward current (l5‐HT) and increase in membrane conductance. Current ‐ voltage relationships for l5‐HTshowed a slight outward rectification and reversal potentials of ‐61.6± 3.1 mV in situ and ‐66± 3.1 mV in primary culture, both values being comparable to the Ecl of Retzius neurons as measured in situ. The results indicate that 5‐HT increases the Cl‐ conductance of Retzius neurons, thereby hyperpolarizing the cell membrane and affecting both the excitability of the neuron and 5‐HT release from it. This could affect the feeding and swimming behaviour of the leech.
Distribution of Secretoneurin‐like Immunoreactivity in Comparison with Substance P‐ and Enkephalin‐like Immunoreactivities in Various Human Forebrain Regions
Authors: Marksteiner J. , Saria A. , Kirchmair R. , Pycha R. , Benesch H. , Fischer‐Colbrie R. , Haring C. , Maier H. , Ransmayr G. 
Published: April 2006

AbstractThe distribution of secretoneurin‐like immunoreactivity, a peptide derived from secretogranin II, was studied by means of immunocytochemistry and compared to the pattern of staining for substance P‐ and enkephalin‐like immunoreactivities in the human basal forebrain, with special reference to the basal ganglia. Secretoneurin‐like immunoreactivity was characterized by gel filtration and reversed‐phase high pressure liquid chromatography analysis. Chromatographic analysis revealed a single peak for secretoneurin‐like immunoreactivity. No secretoneurin‐immunopositive forms of high molecular weight were found. Secretoneurin‐like immunoreactivity appeared mainly in dot‐ and fibre‐like structures. In addition, a band‐like terminal staining (woolly fibres) that has been shown by others for substance P‐ and enkephalin‐like immunoreactivities, was also observed for secretoneurin‐like immunoreactivity. Medium‐sized cells were found arranged in clusters or singly within the caudate and putamen. In the basal ganglia, a high density of secretoneurin‐like immunoreactivity was found in the internal segment of the globus pallidus, the ventral pallidum and in the pars reticulata of the substantia nigra. In these areas the immunostaining appeared mainly as woolly fibres. The bed nucleus of the stria terminalis and medial amygdala displayed a high density of fine beaded secretoneurin‐like immunoreactive fibres, sometimes forming pericellular contacts. The nucleus basalis of Meynert was highly innervated by secretoneurin‐like immunoreactive fibres, mainly in the form of woolly fibres. In general, a large overlap was found between secretoneurin‐ and substance P‐like immunoreactivity in all examined areas of the basal ganglia. In the bed nucleus of the stria terminalis and medial amygdala secretoneurin‐like immunoreactivity was distributed very similarly to enkephalin‐like immunoreactivity. These data provide evidence that in different subsets of neurons and neuronal pathways secretoneurin‐like immunoreactivity coexists with substance P‐ and enkephalin‐like immunoreactivity in several areas of the human brain.
Rapid Decline in the Ability of Entorhinal Axons to Innervate the Dentate Gyrus With Increasing Time in Organotypic Co‐culture
Authors: Woodhams Peter L. , Atkinson D. John , Raisman Geoffrey 
Published: April 2006

AbstractWe have used the species‐specific monoclonal antibodies OM1 and OM4 to identify the histiotypic pattern of projection from late embryonic rat entorhinal explants to the outer molecular layer of the dentate gyrus in organotypic cultures of 6‐day postnatal mouse hippocampal slices. The presence of this entorhinal projection was detectable with the rat‐specific OM1 and OM4 markers after 3–7 days in co‐culture, and confirmed by use of the later‐forming rat neuron‐specific marker Thy‐1.1, which appeared during the second week. Hippocampal slices confronted with control explants of superior colliculus for 4 weeks in culture showed only sparse, non‐specific growth of axons with no histiotypic pattern in the dentate gyrus. In order to assess whether the formation of specific entorhino‐dentate projections in vitro is age‐dependent, embryonic rat entorhinal cortical explants were cultured alone for periods of 1 ‐ 5 weeks before cutting across the halo of axons radiating into the collagen matrix and presenting each with 6‐day‐old mouse hippocampal slices as targets to innervate. After allowing a 2 week period for fibre growth to take place, the density of immunostained axonal outgrowth was scored on a five‐point scale for each weekly interval. The amount of new axon growth when the cuts were made after 1 week was slightly reduced compared to undamaged control cultures. However, outgrowth was greatly diminished when the cuts were made after 2 or 3 weeks, and essentially abolished if the interval was extended to ≥4 weeks. Thus we demonstrate that, although hippocampal slices can survive in organotypic co‐culture with entorhinal explants and maintain previously formed connections, the explants show an age‐related failure in the ability to form new connections. Such a system provides a possible in vitro model for study of the factors influencing the failure of regeneration in the adult central nervous system.
Survival‐promoting and Protein Kinase C‐regulating Roles of Basic FGF for Hippocampal Neurons Exposed to Phorbol Ester, Glutamate and Ischaemia‐like Conditions
Authors: Louis Jean‐Claude , Magal Ella , Gerdes Wilhelm , Seifert Wilfried 
Published: April 2006

AbstractRecent evidence suggests that protein kinase C (PKC) is involved in the pathophysiology of neurodegenerative diseases. We examined the effect of basic fibroblast growth factor (bFGF) on the survival of cultured rat hippocampal neurons exposed to conditions in which PKC is likely to play a role. bFGF reduced neuron damage caused by the PKC‐activating phorbol ester 12‐O‐tetradecanoylphorbol 13‐acetate (TPA), glutamate and ischaemia‐like culture conditions. bFGF was able to counteract the excessive activation of PKC caused by these treatments. Moreover, bFGF prevented the loss of PKC occurring after prolonged exposure to TPA or ischaemia‐like conditions. These results indicate that both the overactivation and the abnormal degradation of PKC can lead to neuron degeneration, and that the neurotrophic competence of bFGF may reside in its ability to regulate and normalize the PKC phosphorylating system.
Immediate Early Gene Expression in the Rat Forebrain Following Striatal Infusion of Quinolinic Acid
Authors: Purkiss R. J. , Legg M. D. , Hunt S. P. , Davies S. W. 
Published: April 2006

AbstractExpression in the rat forebrain of immediate early genes belonging to the fos and jun families was investigated at various time points following an intrastriatal infusion of quinolinic acid. Fos immunoreactivity was rapidly and transiently induced, exhibiting maximal intensity 2 h post‐lesion, and was principally located in neuronal nuclei situated around the periphery of the lesioned striatum, in regions that subsequently show little, if any, neurodegeneration. Fos immunoreactivity was additionally expressed throughout the ipsilateral cortex. In contrast, Jun immunoreactivity, which remained undetectable for 12 h after the lesion, reached its maximal intensity 24 h post‐lesion, at which time it was most densely distributed in neuronal nuclei found within the central lesioned areas of the striatum. In situ hybridization analysis using radiolabeled oligonucleotide probes confirmed this spatial and temporal separation between c‐fos and c‐jun expression within the striatum and extended it further, showing that, whilst jun mRNA displayed very similar expression characteristics to those of c‐fos mRNA, both fos B mRNA and jun D mRNA exhibited induction patterns closely resembling those of c‐jun mRNA. These results clearly suggest that two distinct programmes of immediate early gene expression can be induced in vivo. The rapid (2 h) and transient induction of c‐fos/jun B may well be a response to NMDA receptor activation, whereas the molecular signal for the late (24 h) and sustained induction of c‐jun/ fos B/jun D is currently a focus for our investigations.
Expression of GAP‐43 mRNA in Mouse Spinal Cord Following Unilateral Peripheral Nerve Damage: is There a Contralateral Effect?
Authors: Booth C. M. , Brown M. C. 
Published: April 2006

AbstractTwo new oligonucleotide anti‐sense probes and their corresponding sense probes specific for mouse GAP‐43 mRNA were synthesized and end‐labelled with digoxygenin. They were used to localize GAP‐43 mRNA in the spinal cords of normal mice and in mice 3 and 7 days following unilateral sciatic nerve cut. GAP‐43 mRNA was found to be expressed at low levels in motor and other neurons of the normal spinal cords. As expected from other studies, up‐regulation occurred in the cell bodies of axotomized motor neurons but, in addition, up‐regulation was also observed in the cell bodies of intact motor neurons contralateral to the lesion. Densitometer measurements showed that the up‐regulation of GAP‐43 mRNA was less in the intact, contralateral motor neuron cell bodies than in the axotomized motor neuron cell bodies and furthermore was transient, being higher at 3 days than at 7 days following axotomy. Both anti‐sense probes gave the same result, although differences in cellular localization were observed, and the two sense probes were negative. Probe binding was abolished by pretreatment of the sections with ribonuclease and hybridization was carried out under different conditions of stringency in order to ascertain whether the contralateral expression of GAP‐43 mRNA was a true reflection of its distribution in vivo. There is conflicting evidence on the presence or absence of contralateral effects following unilateral peripheral nerve injury in the literature, and it is suggested that these differences can be accounted for by the methodology and type of probe used.
Non‐quantal Release of Acetylcholine Affects Polyneuronal Innervation on Developing Rat Muscle Fibres
Authors: Vyskočil F. , Vrbová G. 
Published: April 2006

AbstractThe membrane potential at endplates of the rat hemidiaphragm for 9‐day‐old rats increases by 1.8 mV after addition of D‐tubocurarine. The endplate depolarization before the addition of D‐tubocurarine is considered to be due to non‐quantal release (NQR) of acetylcholine (ACh). In the presence of an anticholinesterase this depolarization increased. It was further enhanced by 0.1 ‐1.0 mM Mg2+ and reduced by 4 mM Mg2+ concentration. Thus the regulation of NQR at neuromuscular junctions of developing rat muscles is similar to that seen in adult mammalian species. The effect of NQR of ACh on neuromuscular contacts of muscle fibres from 8–9‐day‐old rat diaphragm and soleus muscles was studied. Pre‐incubating the muscles in solutions where NQR was increased by lowering Mg2+ caused a significant (P < 0.01) reduction of neuromuscular contacts. This reduction did not occur when muscles were incubated in high Mg2+, when NQR is reduced. Increasing quantal release by high Ca2+ also caused a reduction of neuromuscular contacts. Histological examination of soleus muscle fibres treated with an anticholinesterase showed that muscles incubated in solutions with low (0.1 mM) concentrations of Mg2+ had significantly fewer neuromuscular contacts (38%) than those incubated in high concentrations of Mg2+ (61%). It is concluded that the NQR as assessed here contributes to the elimination of polyneuronal innervation during postnatal development of rat muscles.
Effects of Visual Cortex Lesions on Orientation Discrimination of Illusory Contours in the Cat
Authors: De Weerd Peter , Sprague James M. , Raiguel Steven , Vandenbussche Erik , Orban Guy A. 
Published: April 2006

AbstractWe have trained five cats in orientation discrimination using different contours, and compared the deficits caused by lesions of cortical areas 17 and 18 (tier I) to the deficits induced by removal of those areas receiving afferents originating in areas 17 and 18 (tier II). As contour stimuli we used two types of illusory contours and a luminance bar. The two illusory contours were defined by opposed line‐ends. One of them coincided with a luminance gradient whereas the other did not. Tier I lesions destroyed the capacity to discriminate the orientation of both illusory contours, and also caused an important, though less severe, deficit in bar orientation discrimination. The deficits induced by tier I lesions were permanent. Tier II lesions also caused significant deficits in orientation discrimination of illusory contours, but only a negligible deficit in bar orientation discrimination, and this result was not a mere consequence of a difference in difficulty between the tasks involving bars and illusory contours. In addition, tier II lesions differentiated between illusory contour types, the deficit being more pronounced for the illusory contour without luminance gradient than for the one with luminance gradient. In contrast to tier I lesions, tier II lesions allowed significant recovery, leading to small final deficits for all contour types tested.
Complete Axon Arborization of a Single CA3 Pyramidal Cell in the Rat Hippocampus, and its Relationship With Postsynaptic Parvalbumin‐containing Interneurons
Authors: Sik A. , Tamamaki N. , Freund T. F. 
Published: April 2006

AbstractThe complete axon arborization of a single CA3 pyramidal cell has been reconstructed from 32 (60 /μm thick) sections from the rat hippocampus following in vivo intracellular injection of neurobiotin. The same sections were double‐immunostained for parvalbumin‐a calcium‐binding protein selectively present in two types of GABAergic interneurons, the basket and chandelier cells‐in order to map boutons of the pyramidal cell in contact with dendrites and somata of these specific subsets of interneurons visualized in a Golgi‐like manner. The axon of the pyramidal cell formed 15 295 boutons, 63.8% of which were in stratum oriens, 15.4% in stratum pyramidale and 20.8% in stratum radiatum. Only 2.1% of the axon terminals contacted parvalbumin‐positive neurons. Most of these were single contacts (84.7%), but double or triple contacts (15.3%) were also found. The majority of the boutons terminated on dendrites (84.1%) of parvalbumin‐positive cells, less frequently on cell bodies (15.9%). In order to estimate the proportion of contacts representing synapses, 16 light microscopically identified contacts between boutons of the filled pyramidal cell axon and the parvalbumin‐positive targets were examined by correlated electron microscopy. Thirteen of them were found to be asymmetrical synapses, and in the remaining three cases synapses between the labelled profiles could not be confirmed. We conclude that the physiologically effective excitatory connections between single pyramidal cells and postsynaptic inhibitory neurons are mediated by a small number of contacts, mostly by a single synapse. This results in a high degree of convergence and divergence in hippocampal networks.
Long Fibre Growth by Axons of Embryonic Mouse Hippocampal Neurons Microtransplanted into the Adult Rat Fimbria
Authors: Davies S. J. A. , Field P. M. , Raisman G. 
Published: April 2006

AbstractWe have described a method for the microtransplantation of a suspension of a few thousand cells from mid to late embryonic mouse hippocampi into the fimbria of immunosuppressed adult rat hosts. There was close graft‐to‐host contact, across a non‐scarred interface. The transplanted cells included CA3 type pyramids, and were enclosed within the host myelinated fibre tract, whose glial framework was largely undisturbed. Immunohistochemistry of two species‐specific markers (M6 and Thy‐1.2) showed that the donor mouse neurons grew fine (<0.5 μm diameter) axons which extended singly or in fascicles through the rat host fimbria for a maximum distance of at least 10 mm. The donor axons were intimately integrated among and closely aligned to the host tract axons and to the interfascicular glial rows of the host tract. The axons travelled (i) laterally through the ipsilateral fimbria, (ii) medially across the midline in the ventral hippocampal commissure to reach the contralateral fimbria and alveus, and (iii) rostro‐medially to the septum. On approaching the terminal fields appropriate to hippocampal CA3 pyramidal cell axons, the transplant axons gave rise to fine preterminal branches which were continuous with a reticular or amorphous immunoreactivity in the stratum oriens and stratum pyramidale of the ipsilateral hippocampus, and in the lateral and triangular septal nuclei. The donor axons extended along the host fimbria at a rate of ∼ 1 mm per day, reaching their terminal field destinations by ∼1–2 weeks. At 7 weeks the projections were maintained, but with little further extension. These observations indicate that the microenvironment of myelinated adult fibre tracts is permissive for an abundant and rapid growth of axons from transplanted embryonic cell suspensions. These axons can leave host tracts to invade appropriate terminal fields.