bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology of Callosal Axons Interconnecting Areas 17 and 18 of the Cat
Authors: Houzel Jean‐Christophe , Milleret Chantal , Innocenti Giorgio 
Published: April 2006

AbstractSeventeen callosally projecting axons originating near the border between areas 17 and 18 in adult cats were anterogradely labelled with biocytin and reconstructed in 3‐D from serial sections. All axons terminated near the contralateral 17/18 border. However, they differed in their diameter, tangential and radial distributions, and overall geometry of terminal arbors. Diameters of reconstructed axons ranged between 0.45 and 2.25 μm. Most of the axons terminated in multiple terminal columns scattered over several square millimetres of cortex. Thus in general callosal connections are not organized according to simple, point‐to‐point spatial mapping rules. Usually terminal boutons were more numerous in supragranular layers; some were also found in infragranular layers, none in layer IV. However, a few axons were distributed only or mainly in layer IV, others included this layer in their termination. Thus, different callosal axons may selectively activate distinct cell populations. The geometry of terminal arbors defined two types of architecture, which were sometimes represented in the same axon: parallel architecture was characterized by branches of considerable length which supplied different columns or converged onto the same column; serial architecture was characterized by a tangentially running trunk or main branch with radial collaterals to the cortex. These architectures may relate to temporal aspects of inter‐hemispheric interactions. In conclusion, communication between corresponding areas of the two hemispheres appears to use channels with different morphological and probably functional properties.
Intracortical Regionality Represented by Specific Transcription for a Novel Protein, Latexin
Authors: Hatanaka Yumiko , Uratani Yoshihiko , Takiguchi‐Hayash Keiko , Omori Akira , Sato Kazuki , Miyamoto Mami , Arimatsu Yasuyoshi 
Published: April 2006

AbstractThe monoclonal antibody (mAb) PC3.1 recognizes a subset of neurons distributed in the infragranular layers of the lateral neocortex of the rat. Immunoaffinity chromatography with mAb PC3.1 showed that this antibody specifically binds a peptide epitope on a 29 kDa protein named latexin. To study the molecular details of the protein, we isolated four independent cDNA clones for latexin from cDNA libraries of the rat cerebral cortex and whole brain using the amino acid sequences of latexin fragments. Analysis of these cDNA clones showed that the predicted primary structure of latexin consists of 223 amino acids, and has no strict homology to any sequences so far known. Western and Northern blots demonstrated that the latexin and its mRNA were expressed predominantly in neural tissues with some expression in non‐neural tissues. The gene that encodes latexin in the rat appeared to have homologues in other mammalian species and in the chick. In situ hybridization showed that latexin mRNA is synthesized in a subset of neurons in the lateral but not the dorsal neocortex, and that the distribution profile of these neurons is quite similar to that of neurons expressing latexin. These results indicate that latexin is a novel class of neuronal protein which represents intracortical regionality, and suggest that the regional specification of the neocortex involves selective parcellation of neurons which express a particular gene.
Nerve‐evoked Electrical Activity Regulates Molecules and Cells With Immunological Function in Rat Muscle Tissue
Authors: Gundersen Kristian , Mæhlen Jan 
Published: April 2006

AbstractMolecules coded by the major histocompatibility complex (MHC) are present on cell surfaces in most tissues, with the cells of the central nervous system and skeletal muscle as prominent exceptions. We show here that when rat skeletal muscles are rendered inactive by nerve impulse block, expression of MHC class I molecules occurs on the muscle fibres. In addition, the number of cells expressing MHC class II molecules in the muscle interstitium is increased by a factor of three after 2 weeks of impulse blockade. Similar effects obtained by denervation can be counteracted by direct electrical stimulation, Interferon‐γ‐like immunoreactivity accumulates in inactive muscle fibres, and interferon‐γ or a related cytokine could be a link between inactivity and MHC up‐regulation. These findings suggest that nerve‐evoked muscle activity influences not only the phenotype of the muscle cells themselves, but also processes in the interstitium that may increase the immunoreactivity of inactive muscle tissue.
Differential Stimulation of Noradrenaline Release by Reversal of the Na+/Ca2+Exchanger and Depolarization in Chromaffin Cells
Authors: Duarte Emília P. , Baltazar Graça , Carvalho Arsélio P. 
Published: April 2006

AbstractWe compared the effectiveness of Ca2+entering by Na+/Ca2+exchange with that of Ca2+entering by channels produced by membrane depolarization with K+in inducing catecholamine release from bovine adrenal chromaffin cells. The Ca2+influx through the Na+/Ca2+exchanger was promoted by reversing the normal inward gradient of Na+by preincubating the cells with ouabain to increase the intracellular Na+and then removing Na+from the external medium. In this way we were able to increase the cytosolic free Ca2+concentration ([Ca2+]c) by Na+/Ca2+exchange to 325 ± 14 nM, which was similar to the rise in [Ca2+]cobserved upon depolarization with 35 mM K+of cells not treated with ouabain. After incubating the cells with ouabain, K+depolarization raised the [Ca2+]cto 398 ± 31 nM, and the recovery of [Ca2+]cto resting levels was significantly slower. Reversal of the Na+gradient caused an −6‐fold increase in the release of noradrenaline or adrenaline, whereas K+depolarization induced a 12‐fold increase in noradrenaline release but only a 9‐fold increase in adrenaline release. The ratio of noradrenaline to adrenaline release was 1.24 ± 0.23 upon reversal of the Na+/Ca2+exchange, whereas it was 1.83 ± 0.19 for K+depolarization. Reversal of the Na+/Ca2+exchange appeared to be as efficient as membrane depolarization in inducing adrenaline release, in that the relation of [Ca2+]cto adrenaline release was the same in both cases. In contrast, we found that for the same average [Ca2+]c, the Ca2+influx through voltage‐gated channels was much more efficient than the Ca2+entering through the Na+/Ca2+exchanger in inducing noradrenaline release from chromaffin ceils. This greater effectiveness of membrane depolarization in stimulating noradrenaline release suggests that there is a pool of noradrenaline vesicles which is more accessible to Ca2+entering through voltage‐gated Ca2+channels than to Ca2+entering through the Na+/Ca2+exchanger, whereas the adrenaline vesicles do not distinguish between the source of Ca2+.
Control of Impulse Conduction in Long Range Branches of Afferents by Increases and Decreases of Primary Afferent Depolarization in the Rat
Authors: Wall Patrick D. 
Published: April 2006

AbstractIt has been shown previously that impulses in axons of the descending branches of myelinated afferents in rat dorsal columns may suffer a blockade of transmission along their course in the dorsal columns. This paper tests the effect of the mechanism of primary afferent depolarization on the orthodromic movement of impulses in descending dorsal column primary afferent axons originating in the L1 dorsal root. Orthodromic impulses were recorded in the L5 and 6 dorsal columns after stimulation of the L1 dorsal root. Twenty‐seven out of 82 axons (33%) suffered a temporary transmission block if primary afferent depolarization had been induced by L5 stimulation before the L1 stimulus. The tendency to block peaked at 10–15 ms and persisted for up to 30–40 ms. The number of single unit orthodromic impulses originating from the L1 root and recorded during a search of the dorsal columns 15 mm caudal to L1 increased by a factor of 3.1 after the systemic administration of bicuculline (1 mg/kg). The number of single unit orthodromic impulses originating from the L1 root and recorded in axons descending in the dorsal columns 20 mm caudal to the root increased by a factor of 8.7 after the systemic administration of picrotoxin (5 mg/kg). It is concluded that the transmission of impulses in the long range caudally running axons from dorsal roots to dorsal columns may be blocked during primary afferent depolarization and that conduction may be restored by the administration of GABA antagonists.
Archistriatal Lesions Impair the Acquisition of Filial Preferences During Imprinting in the Domestic Chick
Authors: Lowndes M. , Davies D. C. , Johnson M. H. 
Published: April 2006

AbstractThe avian archistriatum has been demonstrated to play a role in agonistic behaviours and avoidance learning. However, the extent of its role in learning is unknown. The involvement of the archistriatum in the learning process of filial imprinting was therefore investigated in day‐old chicks. Bilateral archistriatal lesions, lateral cerebral area lesions or sham archistriatal penetrations were made in dark‐reared, day‐old chicks, which were subsequently exposed to either a rotating red box or blue cylinder for 2 × 1 h training sessions. Three hours later, the approach of chicks to their training object and to the other, novel object was measured. Chicks with archistriatal lesions ran a similar distance towards each stimulus and therefore failed to display a preference for their training object. However, chicks with sham archistriatal penetrations or lateral cerebral area lesions exhibited a significant preference for the object they had been trained upon. These results demonstrate that the archistriatum is essential for the expression of an imprinted preference. All chicks approached their training object significantly more on their second compared to their first training exposure, suggesting that some aspects of imprinting behaviour remain intact in chicks with archistriatal lesions. Taken together with the results of previous work, the current data suggest that the archistriatum may be involved in retention of significant aspects of the imprinting experience, or in motivation to approach imprinting objects.
X‐Ray Study of the Cat Hindlimb During Treadmill Locomotion
Authors: Kuhtz‐Buschbeck J. P. , Boczek‐Funcke A. , Illert M. , Weinhardt C. 
Published: April 2006

AbstractWith pulsed X‐ray cinematography we have analysed the angular excursions of the distal hindlimb joints (proximal interphalangeal, PIP; metatarsophalangeal, MTP; ankle) in cats walking on a treadmill. These distal joints transmit the body weight and the dynamic forces onto the ground. We have included the knee and hip joints in the analysis to relate the angular excursions of the proximal and distal joints and to verify the data previously obtained with external markers on the kinematics of the proximal joints. At the beginning of the stance phase the PIP joints flexed rapidly, the MTP joints extended slowly and the ankle and knee yielded under body weight. Whereas the PIP joints maintained a rather constant angular position of −75° throughout the stance phase, extension continued in the MTP joints from −230° at touch‐down to −270° at the end of the stance phase. Around 50 ms before lift‐off the MTP joints flexed rapidly. Early (−30 ms) after lift‐off this flexion changed into a slow extension. The PIP joints extended swiftly at the stance‐swing transition and moderately at the end of the swing phase. During the middle part of the swing phase they flexed slowly. Small rotatory movements around the long axis of the foot took place in the last 100 ms of the swing phase. The results of this study on the distal joints are discussed in relation to the placing of the paw, to the translation of forward propulsion into a MTP movement and to the lifting of the paw (conventionally described as toe curling). They show a differentiated mechanical interaction between the different distal limb joints during these different phases, which must be known in detail to interpret the corresponding electromyographic data and to understand how the hip is moved forward over the MTP joints which serve as the final pivot during stance.
Comparison of Stress‐induced Changes in Noradrenergic and Serotonergic Neurons in the Rat Hippocampus Using Microdialysis
Authors: Vahabzadeh Abdolvahab , Fillenz Marianne 
Published: April 2006

AbstractThe effects of stress on the serotonergic and noradrenergic projection to the hippocampus were compared in freely moving rats using microdialysis. Stress‐induced changes in 5‐hydroxytryptamine (5‐HT), noradrenaline and their metabolites 5‐hydroxyindoleacetic acid (5‐HIAA) and 3,4‐dihydroxyphenylacetic acid (DOPAC) were measured in the presence of their respective uptake blockers. Local infusion of tetrodotoxin and replacement of Ca2+ with Cd2+ were used to test dependence on impulse traffic. A 5 min tail pinch or 10 min restraint stress increased 5‐HT, 5‐HIAA, noradrenaline and DOPAC levels. A subcutaneous saline injection produced an increase in 5‐HT and DOPAC but not noradrenaline or 5‐HIAA. Although α2 adrenoceptor agonists and antagonists produced changes in the baseline values of noradrenaline and DOPAC, they had little or no effect on stress‐induced changes. Both the abolition of impulse traffic and its enhancement by stress had a greater effect on transmitter than on metabolite levels. Although the responses to stress of the noradrenergic and serotonergic pathway showed many similarities, there was evidence for their activation by separate pathways.
Rat Oligodendrocytes Express Muscarinic Receptors Coupled to Phosphoinositide Hydrolysis and Adenylyl Cyclase
Authors: Cohen R. I. , Almazan G. 
Published: April 2006

AbstractMuscarinic receptors expressed by rat oligodendrocyte primary cultures were examined by measuring changes in second messengers following exposure to carbachol, an acetylcholine analog, and by polymerase chain reaction. Inositol phosphate levels were measured in [3H]myo‐inositol‐labelled young oligodendrocyte cultures following stimulation with carbachol. Atropine, a specific muscarinic antagonist, prevented the carbachol‐induced accumulation of inositol phosphates. The formation of inositol trisphosphate was concentration‐ and time‐dependent, with the peak at 100 μM carbachol and 10 min. Carbachol increased intracellular calcium levels, which were dependent both on the mobilization of intracellular stores and influx of extracellular calcium. In initial experiments with more selective antagonists, the mobilization of intracellular calcium was preferentially inhibited by pirenzepine, a selective M1 antagonist, but not methoctramine, a selective M2 antagonist, suggesting M1 muscarinic receptor involvement. A role for protein kinase C in the regulation of carbachol‐stimulated inositol phosphate formation and intracellular calcium mobilization was demonstrated, as acute pretreatment with phorbol‐12, 13‐myristate acetate abolished the formation of both second messengers. Pretreatment with 100 μM carbachol abolished the 40% increase in the cyclic AMP accumulation stimulated by isoproterenol, a specific β‐adrenergic agonist. In turn, the inhibition was alleviated by pretreatment with atropine, suggesting muscarinic receptor involvement. Polymerase chain reaction carried out with specific ml and m2 muscarinic receptor oligonucleotide primers, confirmed that these cells express, at least, the two muscarinic receptor subtypes. Without excluding the expression of other subtypes, these results suggest that developing oligodendrocytes express ml (M1) and m2 (M2) muscarinic receptors capable of mediating phosphoinositide hydrolysis, mobilization of intracellular calcium and the attenuation of β‐adrenergic stimulation of cyclic AMP formation.
Cholecystokinin in Cortico‐striatal Neurons in the Rat: Immunohistochemical Studies at the Light and Electron Microscopical Level
Authors: Morino P. , Herrera‐Marschitz M. , Castel M. N. , Ungerstedt U. , Varro A. , Dockray G. , Hökfelt T. 
Published: April 2006

AbstractUsing immunohistochemical techniques we have analysed the occurrence of cholecystokinin‐like immunoreactivity (CCK‐LI) in the cortex and striatum of the rat. In the cortex few CCK‐immunoreactive cell bodies, mainly interneurons, could be visualized in normal brains, and a moderately dense network of CCK fibres was also observed. Injections of colchicine into the striatum led to an accumulation, in the surrounding cortex, of CCK‐LI in the initial segment of the axon of numerous cells. In addition, with an antibody to pro‐CCK several cell bodies, many of which with pyramidal shape, could be visualized. Furthermore, retrograde staining of cortical cells after unilateral injection of wheat germ agglutinin into the striatum revealed bilaterally in the cortex a number of labelled cells that also contained pro‐CCK‐LI. In the striatum CCK‐LI was diffusely distributed in fine fibres as well as in patches of fibres located in the medial aspects. After decortication followed by callosotomy these patches disappeared on the side ipsilateral to the lesion, while the pattern of immunoreactivity of several other peptides in the striatum was unaffected. No change was observed on the contralateral side. Decortication or callosotomy alone did not affect the pattern of CCK‐LI. At the ultrastructural level several CCK‐immunoreactive terminals could be observed, mostly with clear, densely packed vesicles and straight asymmetric synaptic contacts with small spines, characteristic for terminals of cortical origin. The results are consistent with the presence of a major, partly crossed, CCK‐containing cortico‐striatal pathway.
Hydrophilic and Amphiphilic Forms of Drosophila Choline Acetyltransferase are Encoded by a Single mRNA
Authors: Salem Natalie , Medilanski Jana , Pellegrinelli Nathalie , Eder‐Colli Lorenza 
Published: April 2006

AbstractWe have previously shown that the enzyme choline‐O‐acetyltransferase (ChAT) exists in a hydrophilic and an amphiphilic form in Drosophila head. A complementary DNA clone of 4.2 kb containing the entire coding region of ChAT was isolated from a cDNA library of Drosophila heads. The cDNA was subcloned in an expression vector and injected into the nucleus of Xenopus oocytes. Injected oocytes expressed high levels of ChAT activity. This activity was inhibited by bromoacetylcholine, a specific inhibitor of the enzyme. In the present study the non‐ionic detergent Triton X‐114 was used to analyse whether the expression of hydrophilic and amphiphilic ChAT was or was not directed by a single cDNA. The two forms of ChAT were found to be synthesized in injected oocytes. Approximately 9% of the recombinant enzyme partitioned as amphiphilic activity. This value was similar to that found for native amphiphilic ChAT in Drosophila heads. Sedimentation in sucrose gradients of amphiphilic enzyme was found to be influenced by the type of detergent present in the gradient whereas this was not the case for hydrophilic ChAT. Hydrophilic and amphiphilic enzyme activities differed in some of their biochemical properties. Amphiphilic ChAT was less sensitive to inhibition by the product acetylcholine than was hydrophilic ChAT. Moreover, amphiphilic ChAT was found to be more resistant than hydrophilic ChAT to heat inactivation at 45°C. These properties were observed for the native as well as for recombinant ChAT. These results demonstrate that the hydrophilic and amphiphilic forms of ChAT are derived from one mRNA.
Transient Production of TGF‐β2 by Postnatal Cerebellar Neurons and its Effect on Neuroblast Proliferation
Authors: Constam Daniel B. , Schmid Peter , Aguzzi Adriano , Schachner Melitta , Fontana Adriano 
Published: April 2006

AbstractThe beta transforming growth factors (TGF‐β) are suggested to regulate developmental processes since they are distinctly expressed during embryogenesis and exert pleiotropic effects on cell growth and differentiation. In the present study the expression of TGF‐β isoforms was investigated in the postnatal and adult mouse brain. As shown by in situ hybridization, TGF‐β2 was expressed in the choroid plexus, hippocampus, dentate gyrus and cerebellar Purkinje neurons, both postnatally and in adults. Furthermore, TGF‐β2 expression was observed postnatally in immature cerebellar neurons of both the external and internal granule cell layers. In the external granule cell layer, the frequency of TGF‐β2 transcripts increased until postnatal day 10 and declined thereafter. In contrast to TGF‐β2, no TGF‐β1 mRNA was detected in cerebellar granule cells. TGF‐β3 expression was widely distributed in postnatal brains although at very low levels. The significance of TGF‐β2 production by cerebellar granule cells was further investigated using cultures of small cerebellar neurons. In these cultures reverse polymerase chain reaction analysis revealed expression of TGF‐β2 but low or almost undetectable levels of TGF‐β1 or ‐β3 mRNAs. Likewise, only TGF‐β2 protein in its latent form was identified in the culture supernatant; the release of TGF‐β2 was maximal during the second day in vitro. Furthermore, TGF‐β was found to inhibit the proliferation of cultured small cerebellar neurons. Taken together, these data suggest that TGF‐β2 is involved in the regulation of postnatal development of the cerebellum.
Is Protein Kinase C Activity Required for the N‐Methyl‐d‐Aspartate‐evoked Rise in Cytosolic Ca2+ in Mouse Striatal Neurons?
Authors: Murphy Nuala P. , Cordier Jocelyne , Glowinski Jacques , Prémont Joël 
Published: April 2006

AbstractThe present study investigates the roles of protein kinase C (PKC) and A (PKA) activities in NMDA‐mediated Ca2+ entry in primary cultures of mouse striatal neurons. Inhibitors of protein kinases, such as sphingosine, RO 31 – 8220 and staurosporine inhibited the NMDA‐ but also the KCI‐induced rise in cytosolic Ca2+. However, the PKA antagonist Rp‐adenosine‐3′,5′monophosphothioate (Rp‐cAMPS) did not alter the NMDA +d‐serine response, whereas it completely suppressed the KCI response. The NMDA +d‐serine‐evoked rise in cytosolic Ca2+, observed in the absence of external Mg2+, was potentiated by the PKC activator phorbol 12‐myristate 13‐acetate (PMA) only when submaximal effective concentrations of this agonist and co‐agonist were used. In addition, the PKC activator did not alter the NMDA +d‐serine‐evoked response in the presence of varying concentrations of Mg2+. Confirming the dependence on PKC activity, desensitization of PKC resulting from long‐term PMA treatment led to an impairment of the NMDA response, leaving the KCI‐induced response intact. We therefore propose that PKC not only potentiates but is also required for the NMDA‐evoked elevation in cytosolic Ca2+ in mouse striatal neurons.
The NO‐cGMP Pathway in Neonatal Rat Dorsal Horn
Authors: Morris R. , Southam E. , Gittins S. R. , de Vente J. , Garthwaite J. 
Published: April 2006

AbstractIncubation of slices of neonatal rat spinal cord with nitric oxide donor compounds produced marked elevations in cyclic guanosine 3′,5’monophosphate (cGMP) levels. The excitatory amino acid receptor agonists N‐methyl‐d‐aspartate (NMDA) and α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionate (AMPA) produced smaller increases, which were blocked by the nitric oxide synthase (NOS) inhibitor Ml‐NG‐nitroarginine (NOArg), indicating that these cGMP responses were mediated by nitric oxide. Immunocytochemistry revealed that, in response to NMDA, cGMP accumulated in a population of small cells and neuropil in laminae II and III of the dorsal horn. This area was also shown, by reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemistry, to contain NOS. These observations suggest that, in the rat spinal cord, NMDA receptor activation is linked to the formation of NO and, hence, of cGMP. This pathway is located selectively in the superficial dorsal horn, consistent with a role in the processing of nociceptive signals.