bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cocaine treatment increases extracellular cholecystokinin (CCK) in the nucleus accumbens shell of awake, freely moving rats, an effect that is enhanced in rats that are behaviorally sensitized to cocaine
Authors: Beinfeld Margery C. , Connolly Kelly J. , Pierce R. Christopher 
Published: March 2003

AbstractCholecystokinin (CCK) is co‐localized with dopamine, is known to modulate dopamine neurotransmission and is involved in behavioral sensitization to psychostimulants. To better understand its role, CCK was measured by microdialysis in the nucleus accumbens (NAC) shell in response to cocaine in drug‐naive rats and in rats that are behaviorally sensitized to cocaine. Basal extracellular levels of CCK in drug‐naive rats were 0.17 pg/20 min fraction, while in cocaine‐sensitized rats, they were significantly higher (0.56 pg). Treating drug‐naive rats with cocaine caused a significant increase in CCK to 0.58 pg. Cocaine treatment of cocaine‐sensitized rats increased CCK to 0.98. When analyzed as a function of time after cocaine treatment, these increases were sustained and were significantly different from CCK levels of saline‐treated rats. In cocaine‐sensitized rats, CCK levels following cocaine treatment were also significantly higher than levels in drug‐naive animals receiving a single injection of cocaine. These results provide evidence for an activation of the mesolimbic and/or cerebral cortical CCK system in response to repeated cocaine administration. These results provide a neurochemical basis for an important role of CCK (via modulation of dopamine neurotransmission) in expression of cocaine sensitization.
Dibasic cleavage site is required for sorting to the regulated secretory pathway for both pro‐ and neuropeptide Y
Authors: Brakch Noureddine , Allemandou Flore , Cavadas Claudia , Grouzmann Eric , Brunner Hans R. 
Published: March 2003

AbstractTo investigate the signals governing routing of biologically active peptides to the regulated secretory pathway, we have expressed mutated and non‐mutated proneuropeptide Y (ProNPY) in pituitary‐derived AtT20 cells. The mutations were carried out on dibasic cleavage site and or ProNPY C‐terminal sequence. Targeting to the regulated secretory pathway was studied using protein kinase A (8‐BrcAMP), protein kinase C (phorbol myristate acetate) specific activators and protein synthesis inhibitor cycloheximide, and by pulse chase. The analysis of expressed peptides in cells and culture media indicated that: neuropeptide Y (NPY) and ProNPY were differently secreted, whilst NPY was exclusively secreted via regulatory pathway; ProNPY was secreted via regulated and constitutive‐like secretory pathways. ProNPY secretion behaviour was not Proteolytic cleavage efficiency‐dependent. The dibasic cleavage was essential for ProNPY and NPY cAMP‐dependent regulated secretion and may have function as a retention signal.
Time‐dependence of the contribution of pyruvate carboxylase versus pyruvate dehydrogenase to rat brain glutamine labelling from [1–13C]glucose metabolism
Authors: Merle Michel , Bouzier‐Sore Anne‐Karine , Canioni Paul 
Published: March 2003

Abstract[1–13C]glucose metabolism in the rat brain was investigated after intravenous infusion of the labelled substrate. Incorporation of the label into metabolites was analysed by NMR spectroscopy as a function of the infusion time: 10, 20, 30 or 60 min. Specific enrichments in purified mono‐ and dicarboxylic amino acids were determined from 1H‐observed/13C‐edited and 13C‐NMR spectroscopy. The relative contribution of pyruvate carboxylase versus pyruvate dehydrogenase (PC/PDH) to amino acid labelling was evaluated from the enrichment difference between either C2 and C3 for Glu and Gln, or C4 and C3 for GABA, respectively. No contribution of pyruvate carboxylase to aspartate, glutamate or GABA labelling was evidenced. The pyruvate carboxylase contribution to glutamine labelling varied with time. PC/PDH decreased from around 80% after 10 min to less than 30% between 20 and 60 min. This was interpreted as reflecting different labelling kinetics of the two glutamine precursor glutamate pools: the astrocytic glutamate and the neuronal glutamate taken up by astrocytes through the glutamate‐glutamine cycle. The results are discussed in the light of the possible occurrence of neuronal pyruvate carboxylation. The methods previously used to determine PC/PDH in brain were re‐evaluated as regards their capacity to discriminate between astrocytic (via pyruvate carboxylase) and neuronal (via malic enzyme) pyruvate carboxylation.
Interleukin‐4 and interleukin‐10 modulate nuclear factor κB activity and nitric oxide synthase‐2 expression in Theiler's virus‐infected brain astrocytes
Authors: Molina‐Holgado Eduardo , Arévalo‐Martín Angel , Castrillo Antonio , Boscá Lisardo , Vela José M. , Guaza Carmen 
Published: March 2003

AbstractIn brain astrocytes, nuclear factor κB (NF‐κB) is activated by stimuli that produce cellular stress causing the expression of genes involved in defence, including the inducible nitric oxide synthase (NOS‐2). Theiler's murine encephalomyelitis virus (TMEV) induces a persistent CNS infection and chronic immune‐mediated demyelination, similar to human multiple sclerosis. The cytokines interleukin (IL)‐4 and IL‐10 inhibit the expression of proinflammatory cytokines, counteracting the inflammatory process. Our study reports that infection of cultured astrocytes with TMEV resulted in a time‐dependent phosphorylation of IκBα, degradation of IκBα and IκBβ, activation of NF‐κB and expression of NOS‐2. The proteasome inhibitor MG‐132 blocked TMEV‐induced nitrite accumulation, NOS‐2 mRNA expression and phospho‐IκBα degradation, suggesting NF‐κB‐dependent NOS‐2 expression. Pretreatment of astrocytes with IL‐4 or IL‐10 decreased p65 nuclear translocation, NF‐κB binding activity and NOS‐2 transcription. IL‐4 and IL‐10 caused an accumulation of IκBα in TMEV‐infected astrocytes without affecting IκBβ levels. The IκB kinase activity and the degradation rate of both IκBs were not modified by either cytokine, suggesting de novo synthesis of IκBα. Indeed, IL‐4 or IL‐10 up‐regulated IκBα mRNA levels after TMEV infection. Therefore, the accumulation of IκBα might impair the translocation of the NF‐κB to the nucleus, mediating the inhibition of NF‐κB activity. Overall, these data suggest a novel mechanism of action of IL‐4 and IL‐10, which abrogates NOS‐2 expression in viral‐infected glial cells.
Glycine transporter isoforms show differential subcellular localization in PC12 cells
Authors: Geerlings Arjan , Núñez Enrique , Rodenstein Lara , López‐Corcuera Beatriz , Aragón Carmen 
Published: March 2003

AbstractThe subcellular localization of glycine transporters one (GLYT1) and two (GLYT2) stably expressed in PC12 cells has been studied. To facilitate visualization, enhanced green fluorescent protein (GFP) was fused to the amino terminus of both glycine transporters. Functional analysis of the GFP–GLYT1 and GFP–GLYT2 stable cell lines demonstrated that they exhibited high affinity for glycine and the characteristic properties of both glycine transporter subtypes. The GFP‐coupled transporters were differently distributed throughout the cell. GFP–GLYT1 was mainly localized on the plasma membrane, whereas most of GFP–GLYT2 was present on large dense‐core vesicles and endosomes. Both transporters were absent from the synaptic vesicle population in PC12 cells.
One melanocortin 4 and two melanocortin 5 receptors from zebrafish show remarkable conservation in structure and pharmacology
Authors: Ringholm Aneta , Fredriksson Robert , Poliakova Natalia , Yan Yi‐Lin , Postlethwait John H. , Larhammar Dan , Schiöth Helgi B. 
Published: March 2003

AbstractWe report the cloning, genome mapping, functional expression, pharmacology and anatomical distribution of three melanocortin (MC) receptors from zebrafish (z). Phylogenetic analysis showed with high bootstrap support that these genes represent one MC4 receptor and two MC5 receptors. Chromosomal mapping showed conserved synteny between regions containing zMC4 and human (h) MC4 receptors, whereas the two zMC5 receptor genes map on chromosome segments in which the zebrafish has several genes with two orthologues of a single mammalian gene. It is likely that the two copies of zMC5 receptors arose through a separate duplication in the teleost lineage. The zMC4, zMC5a, and zMC5b receptors share 70–71% overall amino acid identity with the respective human orthologues and over 90% in three TM regions believed to be most important for ligand binding. All three zebrafish receptors also show pharmacological properties remarkably similar to their human orthologues, with similar affinities and the same potency order, when expressed and characterized in radioligand binding assay for the natural melanocyte stimulating hormone (MSH) peptides α‐, β‐, and γ‐MSH. Stimulation of transfected mammalian cells with α‐MSH caused a dose‐dependent increase in intracellular cAMP levels for all three zebrafish receptors. All three genes were expressed in the brain, eye, ovaries and gastrointestinal tract, whereas the zMC5b receptor was also found in the heart, as determined by RT‐PCR. Our studies, which represent the first characterization of MC receptors in a nonamniote species, indicate that the MC receptor subtypes arose very early in vertebrate evolution. Important pharmacological and functional properties, as well as gene structure and syntenic relationships have been highly conserved over a period of more than 400 million years implying that these receptors participate in vital physiological functions.
Analysis of genes induced in peripheral nerve after axotomy using cDNA microarrays
Authors: Kubo Tateki , Yamashita Toshihide , Yamaguchi Atsushi , Hosokawa Ko , Tohyama Masaya 
Published: March 2003

AbstractOne of the most striking features of neurons in the mature peripheral nervous system is their ability to survive and to regenerate their axons following axonal injury. To perform a comprehensive survey of the molecular mechanisms that underlie peripheral nerve regeneration, we analyzed a cDNA library derived from the distal stumps of post‐injured sciatic nerve which was enriched in non‐myelinating Schwann cells using cDNA microarrays. The number of up‐ and down‐regulated genes in the transected sciatic nerve was 370 and 157, respectively, of the 9596 spotted genes. In the up‐regulated group, the number of known genes was 216 and the number of expressed sequence tag (EST) sequences was 154. In the down‐regulated group, the number of known genes was 103 and that of EST sequences was 54. We obtained several genes that were previously reported to be involved in regeneration of the injured neurons, such as cathepsin D, ninjurin 1, tenascin C, and co‐receptor for glial cell line‐derived neurotrophic factor family of trophic factors. In addition to unknown genes, there seemed to be a lot of annotated genes whose role in nerve regeneration remains unknown.
Antiproliferative action of valproate is associated with aberrant expression and nuclear translocation of cyclin D3 during the C6 glioma G1 phase
Authors: Bacon Christopher L. , Gallagher Helen C. , Haughey John C. , Regan Ciaran M. 
Published: March 2003

AbstractCell cycle progression is tightly regulated by cyclins, cyclin‐dependent kinases (cdks) and related inhibitory phophatases. Here, we employed mitotic selection to synchronize the C6 glioma cell cycle at the start of the G1 phase and mapped the temporal regulation of selected cyclins, cdks and inhibitory proteins throughout the 12 h of G1 by immunoblot analysis. The D‐type cyclins, D3 and D1, were differentially expressed during the C6 glioma G1 phase. Cyclin D1 was up‐regulated in the mid‐G1 phase (4–6 h) while cyclin D3 expression emerged only in late G1 (9–12 h). The influence of the anticonvulsant agent valproic acid (VPA) on expression of cyclins and related proteins was determined, since its teratogenic potency has been linked to cell cycle arrest in the mid‐G1 phase. Exposure of C6 glioma to VPA induced a marked up‐regulation of cyclin D3 and decreased expression of the proliferating cell nuclear antigen. In synchronized cell populations, increased expression of cyclin D3 by VPA was detected in the mid‐G1 phase (3–5 h). Immunocytochemical localization demonstrated rapid intracellular translocation of cyclin D3 to the nucleus following VPA exposure, suggesting that VPA‐induced cell cycle arrest may be mediated by precocious activation of cyclin D3 in the G1 phase.
Kynurenine 3‐mono‐oxygenase inhibitors attenuate post‐ischemic neuronal death in organotypic hippocampal slice cultures
Authors: Carpenedo Raffaella , Meli Elena , Peruginelli Fiamma , Pellegrini‐Giampietro Domenico E. , Moroni Flavio 
Published: March 2003

AbstractKynurenine 3‐mono‐oxygenase (KMO) inhibitors reduce 3‐hydroxykynurenine (3‐HK) and quinolinic acid (QUIN) neosynthesis and facilitate kynurenine metabolism towards kynurenic acid (KYNA) formation. They also reduce tissue damage in models of focal or transient global cerebral ischemia in vivo. We used organotypic hippocampal slice cultures exposed to oxygen and glucose deprivation (OGD) to investigate KMO mechanism(s) of neuroprotective activity. Exposure of the slices to 30 min of OGD caused CA1 pyramidal cell death and significantly decreased the amount of KYNA released in the incubation medium. The KMO inhibitors (m‐nitrobenzoyl)‐alanine (30–100 µm) or 3,4‐dimethoxy‐[‐N‐4‐(nitrophenyl)thiazol‐2yl]‐benzenesulfonamide (1–10 µm) reduced post‐ischemic neuronal death and increased KYNA concentrations in slice incubation media. The maximal concentration of KYNA detected in the incubation media of slices treated with KMO inhibitors was approximately 50 nm and was too low to efficiently interact with α7 nicotinic acetylcholine receptors or with the glycineb site of N‐methyl‐d‐aspartate (NMDA) receptors. On the other hand, the addition of either 3‐HK or QUIN (1–10 µm) to OGD‐exposed hippocampal slices prevented the neuroprotective activity of KMO inhibitors. Our results suggest that KMO inhibitors reduce the neuronal death found in the CA1 region of organotypic hippocampal slices exposed to 30 min of OGD by decreasing the local synthesis of 3‐HK and QUIN.
Characterization of chemokines and their receptors in the central nervous system: physiopathological implications
Authors: Bajetto Adriana , Bonavia Rudy , Barbero Simone , Schettini Gennaro 
Published: March 2003

AbstractChemokines represent key factors in the outburst of the immune response, by activating and directing the leukocyte traffic, both in lymphopoiesis and in immune surveillance. Neurobiologists took little interest in chemokines for many years, until their link to acquired immune deficiency syndrome‐associated dementia became established, and thus their importance in this field has been neglected. Nevertheless, the body of data on their expression and role in the CNS has grown in the past few years, along with a new vision of brain as an immunologically competent and active organ. A large number of chemokines and chemokine receptors are expressed in neurons, astrocytes, microglia and oligodendrocytes, either constitutively or induced by inflammatory mediators. They are involved in many neuropathological processes in which an inflammatory state persists, as well as in brain tumor progression and metastasis. Moreover, there is evidence for a crucial role of CNS chemokines under physiological conditions, similar to well known functions in the immune system, such as proliferation and developmental patterning, but also peculiar to the CNS, such as regulation of neural transmission, plasticity and survival.
Hydroxylated residues influence desensitization behaviour of recombinant α3 glycine receptor channels
Authors: Breitinger Hans‐Georg , Villmann Carmen , Rennert Janine , Ballhausen Diana , Becker Cord‐Michael 
Published: March 2003

AbstractThe human glycine receptor subunit α3 exists in two splice variants (α3K/L), with α3L bearing an additional segment of 15 amino acids within the cytoplasmic TM3‐4 loop. Homomeric α3K glycine receptors show faster desensitization than α3L receptors. Ion channel properties were compared of α3L, α3K, and of the triple mutant α3LΔOH = α3L(T358A/Y367F/S370A), where hydroxyl functions of the spliced insert had been removed by site‐directed mutagenesis. Upon recombinant expression in HEK 293 cells, patch‐clamp recording experiments revealed that removal of hydroxyl functions primarily affected receptor desensitization. The fraction of non‐desensitizing current was 68 ± 13% for α3L, 21 ± 13% for α3K, and 48 ± 16% for α3LΔOH. Desensitization time constants at saturating glycine concentration were 8.4 ± 2.8 s, 1.9 ± 2.3 s, and 2.8 ± 0.4 s, for α3L, α3K, and the triple mutant α3LΔOH, respectively. In contrast, single‐channel and whole‐cell properties were similar for all three constructs. Thus, ion channel activation, desensitization, and conductance properties are independently controlled by distinct structural elements. Hydroxyl functions within the M3‐4 loop of the glycine receptor α3 subunit are crucial, but not exclusive, determinants of receptor desensitization.
Antiproliferative effect of nitric oxide on epidermal growth factor‐responsive human neuroblastoma cells
Authors: Murillo‐Carretero Maribel , Ruano María José , Matarredona Esperanza R. , Villalobo Antonio , Estrada Carmen 
Published: March 2003

AbstractAddition of nitric oxide (NO) donors to NB69 neuroblastoma cells produced a cGMP‐independent decrease in cell proliferation, without affecting cell viability or apoptosis. The potency of short half‐life NO donors was higher when cell proliferation was stimulated by epidermal growth factor (EGF), as compared with cultures exposed to fetal calf serum (FCS). Immunoprecipitation and western blot analysis of the EGF receptor (EGFR) revealed a significant reduction of its EGF‐induced tyrosine phosphorylation in cells treated with the NO donor 2‐(N,N‐diethylamino)‐diazenolate‐2‐oxide (DEA‐NO). When total cell lysates were subjected to western blotting, we observed that DEA‐NO also reduced tyrosine phosphorylation in EGF‐activated phosphoproteins, but not in those proteins whose tyrosine phosphorylation was evident in the absence of EGF. The effect of NO on EGFR transphosphorylation was concentration‐dependent and transient, with a total recovery observed between 1.5 and 3 h after addition of DEA‐NO to the cells. When cells were incubated for 15 min with DEA‐NO and then washed, the EGFR transphosphorylation returned to control levels immediately, indicating that the interaction of NO with the receptor molecule was fully reversible. NB69 cells expressed both the neuronal and the inducible isoforms of NO synthase (NOS) when cultured in the presence of FCS; under this condition, the NOS inhibitor, Nω‐nitro‐l‐arginine methyl ester, produced a small but significant increase in cell proliferation. The results suggest that NO is an endogenous antimitotic agent and that its interaction with EGFR contributes to cytostasis in NB69 cells.
Antibodies to L‐periaxin in sera of patients with peripheral neuropathy produce experimental sensory nerve conduction deficits
Authors: Lawlor Mike W. , Richards Michael P. , De Vries George H. , Fisher Morris A. , Stubbs Evan B. 
Published: March 2003

AbstractL‐Periaxin is a PDZ‐domain protein localized to the plasma membrane of myelinating Schwann cells and plays a key role in the stabilization of mature myelin in peripheral nerves. Mutations in L‐periaxin have recently been described in some patients with demyelinating peripheral neuropathy, suggesting that disruption of L‐periaxin function may result in nerve injury. In this study, we report the presence of autoantibodies to L‐periaxin in sera from two of 12 patients with diabetes mellitus (type 2)‐associated neuropathy and three of 17 patients with IgG monoclonal gammopathy of undetermined significance (MGUS) neuropathy, an autoimmune peripheral nerve disorder. By comparison, anti‐L‐periaxin antibodies were not present in sera from nine patients with IgM MGUS neuropathy or in sera from 10 healthy control subjects. The effect of anti‐L‐periaxin serum antibody on peripheral nerve function was tested in vivo by intraneural injection. Sera containing anti‐L‐periaxin antibody, but not sera from age‐matched control subjects, injected into the endoneurium of rat sciatic nerve significantly (p < 0.005, n = 3) attenuated sensory‐evoked compound muscle action potential (CMAP) amplitudes in the absence of temporal dispersion. In contrast, motor‐evoked CMAP amplitudes and latencies were not affected by intraneural injection of sera containing anti‐L‐periaxin antibody. Light and electron microscopy of anti‐L‐periaxin serum‐injected nerves showed morphologic evidence of demyelination and axon enlargement. Depleting sera of anti‐L‐periaxin antibodies neutralized the serum‐mediated effects on nerve function and nerve morphology. Together, these data support anti‐L‐periaxin antibody as the pathologic agent in these serum samples. We suggest that anti‐L‐periaxin antibodies, when present in sera of patients with IgG MGUS‐ or diabetes‐associated peripheral neuropathy, may elicit sensory nerve conduction deficits.
Altered processing of amyloid precursor protein in the human neuroblastoma SH‐SY5Y by chronic hypoxia
Authors: Webster Nicola J. , Green Kim N. , Peers Chris , Vaughan Peter F. T. 
Published: March 2003

AbstractAlzheimer's disease (AD) is more prevalent following an ischemic or hypoxic episode, such as stroke. Indeed, brain levels of amyloid precursor protein (APP) and the cytotoxic amyloid β peptide (Aβ) fragment are enhanced in these patients and in animal models following experimental ischaemia. We have investigated the effect of chronic hypoxia (CH; 2.5% O2, 24 h) on processing of APP in the human neuroblastoma, SH‐SY5Y. We demonstrate that constitutive and muscarinic‐receptor‐enhanced secretion of the α‐secretase cleaved fragment of APP, sAPPα, was reduced by ∼60% in CH cells. The caspase inhibitor BOC‐D(Ome)FMK did not reverse this effect of CH, and CH cells were as viable as controls, based on MTT assays. Thus, loss of sAPPα is not related to cell death or caspase processing of APP. Pre‐incubation with antioxidants did not reverse the effect of CH, and the effect could not be mimicked by H2O2, discounting the involvement of reactive oxygen species in hypoxic loss of sAPPα. CH did not affect muscarinic activation of extracellular‐signal regulated kinase. However, expression of ADAM 10 (widely believed to be α‐secretase) was decreased approximately 50% following CH. Thus, CH selectively decreases processing of APP by the α‐secretase pathway, most likely by decreasing levels of ADAM 10.