bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular profiling of midbrain dopamine regions in cocaine overdose victims
Authors: Tang Wen‐Xue , Fasulo Wendy H. , Mash Deborah C. , Hemby Scott E. 
Published: July 2010

AbstractChronic cocaine use in humans and animal models is known to lead to pronounced alterations in neuronal function in brain regions associated with drug reinforcement. To evaluate whether the alterations in gene expression in cocaine overdose victims are associated with specific dopamine populations in the midbrain, cDNA arrays and western blotting were used to compare gene and protein expression patterns between cocaine overdose victims and age‐matched controls in the ventral tegmental area (VTA) and lateral substantia nigra (l‐SN). Array analysis revealed significant up‐regulation of numerous transcripts in the VTA, but not in the l‐SN, of cocaine overdose victims including NMDAR1, GluR2, GluR5 and KA2 receptor mRNA (p < 0.05). No significant alterations between overdose victims and controls were observed for GluR1, R3 or R4 mRNA levels. Correspondingly, western blot analysis revealed VTA‐selective up‐regulation of CREB (p < 0.01), NMDAR1 (p < 0.01), GluR2 (p < 0.05), GluR5 (p < 0.01) and KA2 (p < 0.05) protein levels of cocaine overdose victims. The present results indicate that selective alterations of CREB and certain ionotropic glutamate receptor (iGluR) subtypes appear to be associated with chronic cocaine use in humans in a region‐specific manner. Moreover, as subunit composition determines the functional properties of iGluRs, the observed changes may indicate alterations in the excitability of dopamine transmission underlying long‐term biochemical and behavioral effects of cocaine in humans.
The C‐type natriuretic peptide precursor of snake brain contains highly specific inhibitors of the angiotensin‐converting enzyme
Authors: Hayashi Mirian A. F. , Murbach Alessandra F. , Ianzer Danielle , Portaro Fernanda C. V. , Prezoto Benedito C. , Fernandes Beatriz L. , Silveira Paulo F. , Silva Carlos A. , Pires Raquel S. , Britto Luiz R. G. , Dive Vincent , Camargo Antonio C. M. 
Published: July 2010

AbstractThe bradykinin‐potentiating peptides from Bothrops jararaca venom are the most potent natural inhibitors of the angiotensin‐converting enzyme. The biochemical and biological features of these peptides were crucial to demonstrate the pivotal role of the angiotensin‐converting enzyme in blood pressure regulation. In the present study, seven bradykinin‐potentiating peptides were identified within the C‐type natriuretic peptide precursor cloned from snake brain. The bradykinin‐potentiating peptides deduced from the B. jararaca brain precursor are strong in vitro inhibitors of the angiotensin‐converting enzyme (nanomolar range), and also potentiate the bradykinin effects in ex vivo and in vivo experiments. Two of these peptides are novel bradykinin‐potentiating peptides, one of which displays high specificity toward the N‐domain active site of the somatic angiotensin‐converting enzyme. In situ hybridization studies revealed the presence of the bradykinin‐potentiating peptides precursor mRNAs in distinct regions of the B. jararaca brain, such as the ventromedial hypothalamus, the paraventricular nuclei, the paraventricular organ, and the subcommissural organ. The biochemical and pharmacological properties of the brain bradykinin‐potentiating peptides, their presence within the neuroendocrine regulator C‐type natriuretic peptide precursor, and their expression in regions of the snake brain correlated to neuroendocrine functions, strongly suggest that these peptides belong to a novel class of endogenous vasoactive peptides.
Role of protein kinase A in GABAAreceptor dysfunction in CA1 pyramidal cells following chronic benzodiazepine treatment
Authors: Lilly Scott M. , Zeng X. J. , Tietz E. I. 
Published: July 2010

AbstractOne‐week treatment with the benzodiazepine (BZ) flurazepam (FZP), results in anticonvulsant tolerance, associated with reduced GABAAreceptor (GABAR) subunit protein and miniature inhibitory post‐synaptic current (mIPSC) amplitude in CA1 neurons of rat hippocampus. Because protein kinase A (PKA) has been shown to modulate GABAR function in CA1 pyramidal cells, the present study assessed whether GABAR dysfunction is associated with changes in PKA activity. Two days after 1‐week FZP treatment, there were significant decreases in basal (− 30%) and total (− 25%) PKA activity, and a 40% reduction in PKA RIIβ protein in the insoluble fraction of CA1 hippocampus. The soluble component of CA1 showed a significant increase in basal (100%) but not total PKA activity. Whole‐cell recordingin vitroshowed a 50% reduction in mIPSC amplitude in CA1 pyramidal cells, with altered sensitivity to PKA modulators. Neurons from FZP‐treated rats responded to 8‐bromo‐cAMP with a significant increase (31%) in mIPSC amplitude. Likewise, vasoactive intestinal polypeptide (VIP), an endogenous PKA activator, caused a significant 36% increase in mIPSC amplitude in FZP‐treated cells. Neither agent had a significant effect on mIPSC amplitude in control cells. This study supports a role for PKA in GABAR dysfunction after chronic FZP treatment.
Biochemical and molecular studies using human autopsy brain tissue
Authors: Hynd Matthew R. , Lewohl Joanne M. , Scott Heather L. , Dodd Peter R. 
Published: July 2010

AbstractThe use of human brain tissue obtained at autopsy for neurochemical, pharmacological and physiological analyses is reviewed. RNA and protein samples have been found suitable for expression profiling by techniques that include RT‐PCR, cDNA microarrays, western blotting, immunohistochemistry and proteomics. The rapid development of molecular biological techniques has increased the impetus for this work to be applied to studies of brain disease. It has been shown that most nucleic acids and proteins are reasonably stable post‐mortem. However, their abundance and integrity can exhibit marked intra‐ and intercase variability, making comparisons between case‐groups difficult. Variability can reveal important functional and biochemical information. The correct interpretation of neurochemical data must take into account such factors as age, gender, ethnicity, medicative history, immediate ante‐mortem status, agonal state and post‐mortem and post‐autopsy intervals. Here we consider issues associated with the sampling of DNA, RNA and proteins using human autopsy brain tissue in relation to various ante‐ and post‐mortem factors. We conclude that valid and practical measures of a variety of parameters may be made in human brain tissue, provided that specific factors are controlled.
4‐Hydroxynonenal contributes to NGF withdrawal‐induced neuronal apoptosis
Authors: Bruckner Shane R. , Perry George , Estus Steven 
Published: July 2010

AbstractReactive oxygen species are a necessary triggering event for apoptosis of sympathetic neurons after nerve growth factor (NGF) withdrawal. Reactive oxygen species can lead to the generation of 4‐hydroxynonenal (HNE), a highly reactive aldehyde that forms adducts with proteins. This covalent modification can activate or inhibit signal transduction pathways involved in the induction of apoptosis. This process may be clinically relevant because HNE‐adduct immunoreactivity increases in several disease states. Here we evaluate the role of HNE‐adducts in sympathetic neurons undergoing NGF‐deprivation‐induced apoptosis, a model of developmental programmed cell death. We show that HNE‐adduct immunoreactivity is dramatically increased after NGF‐withdrawal in an NADPH oxidase‐dependent manner. Moreover, HNE‐adducts appear to contribute to NGF‐deprivation‐induced apoptotic signal transduction because microinjected HNE‐adduct antiserum protects sympathetic neurons from NGF withdrawal. In conclusion, this report suggests the direct contribution of endogenously generated HNE in the stimulation of apoptotic signal transduction in neurons.
Attenuation of signal flow from P2Y6receptor by protein kinase C‐α in SK‐N‐BE(2)C human neuroblastoma cells
Authors: Lee Hyun , Choi Bo‐Hwa , Suh Byung‐Chang , Lee Sun‐Kyong , Kim Kyong‐Tai 
Published: July 2010

AbstractExtracellular nucleotides exert a variety of biological actions through several kinds of P2 receptors in many tissues and cell types. We found that treatment with nucleotides increases intracellular Ca2+concentration ([Ca2+]i) in SK‐N‐BE(2)C human neuroblastoma cells with a following order of potency: UDP > UTP > ADP >> ATP. Reverse transcription‐polymerase chain reaction (RT‐PCR) analysis showed that specific mRNAs coding for human P2Y1, P2Y4, and P2Y6receptors were expressed in the cells, but Northern blot analysis revealed that P2Y6receptors were the predominant type. Activation of protein kinase C‐α by treatment with 1 µmphorbol 12‐myristate 13‐acetate dramatically inhibited both the UDP‐induced [Ca2+]irise and inositol 1,4,5‐trisphosphate (IP3) generation, whereas incubation with pertussis toxin had little effect on the responses. The UDP‐induced [Ca2+]irise and IP3production were maintained up to 30 min after stimulation, while bradykinin‐induced responses rapidly decreased to the basal level within 5 min of stimulation. Pretreatment of cells with the maximal effective concentration of UDP reduced the subsequent carbachol‐ or bradykinin‐induced [Ca2+]irise without inhibition of IP3generation. Neuronal differentiation of the cells by treatment with retinoic acid for 7 days did not change the expression level of P2Y6receptors. Taken together, the data indicate that P2Y6receptors highly responsive to diphosphonucleotide UDP are endogenously expressed in the human neuroblastoma SK‐N‐BE(2)C cells and that they are involved in the modulation of other phospholipase C‐coupled receptor‐mediated Ca2+mobilization by depleting the IP3‐sensitive Ca2+stores.
Differential subcellular localization of two dopamine D2receptor isoforms in transfected NG108‐15 cells
Authors: Takeuchi Yusuke , Fukunaga Kohji 
Published: July 2010

AbstractThe dopamine D2receptor (D2R) is target for antipsychotic drugs and associated with several neuropsychiatric disorders. D2R has a long third cytoplasmic loop and a short carboxyl‐terminal cytoplasmic tail. It exists as two alternatively spliced isoforms, termed D2LR and D2SR, which differ in the presence and absence, respectively, of a 29 amino acid insert in the third cytoplasmic loop. To evaluate the differential roles of the two D2R isoforms, we transfected both isoforms into NG108‐15 cells and observed their subcellular localization by a confocal laser scanning light microscope. D2SR was predominantly localized at the plasma membrane, whereas D2LR was mostly retained in the perinuclear region around the Golgi apparatus. Using a yeast two hybrid system with a mouse brain cDNA library and coimmunoprecipitation assay, we found that heart‐type fatty acid binding protein (H‐FABP) interacts with D2LR but not with D2SR. H‐FABP is a cytosolic protein involved in binding and transport of fatty acids. Overexpressed H‐FABP and endogenous H‐FABP were colocalized with the intracellular D2LR in NG108‐15 cells. Furthermore, in the rat striatum, H‐FABP was detected in the D2R‐expressing neurons. From these results, H‐FABP is associated with D2LR, and may thereby modulate the subcellular localization and function of D2LR.
Increased synaptosomal dopamine content and brain concentration of paraquat produced by selective dithiocarbamates
Authors: Barlow Brian K. , Thiruchelvam Mona J. , Bennice Lisa , Cory‐Slechta Deborah A. , Ballatori Nazzareno , Richfield Eric K. 
Published: July 2010

AbstractExposure to pesticides may be a risk factor for Parkinson's disease based on epidemiologic data in humans, animal models andin vitrostudies. Different dithiocarbamate pesticides potentiate the toxicity of both 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine and paraquat in mouse models of Parkinsonism by an unknown mechanism. This study examined the effects of commercially used dithiocarbamates on [3H]dopamine transport in striatal synaptosomal vesicles and on the concentration of [14C]paraquatin vivoin mice. Different ethylenebis‐dithiocarbamates and diethyl‐dithiocarbamate increased dopamine accumulation in synaptosomes, whereas dimethyl‐dithiocarbamate and methyl‐dithiocarbamate did not. Increased dopamine accumulation in synaptosomes was dose dependent and was related to the carbon backbone of these molecules. The dithiocarbamates that increased accumulation of dopamine did not alter the influx of dopamine, but rather delayed the efflux out of synaptosomes. These same dithiocarbamates also increased the tissue content of [14C]paraquatin vivoby a mechanism that appeared to be distinct from the dopamine transporter. There was a consistent relationship between the dithiocarbamates that increased synaptosomal accumulation of dopamine and tissue content of paraquat, with those previously demonstrated to enhance paraquat toxicityin vivo. These results suggest that selective dithiocarbamates may alter the kinetics of different endogenous and exogenous compounds to enhance their neurotoxicity.
Systemic morphine‐induced release of serotonin in the rostroventral medulla is not mimicked by morphine microinjection into the periaqueductal gray
Authors: Taylor Bradley K. , Basbaum Allan I. 
Published: July 2010

AbstractWe usedin vivomicrodialysis in awake rats to test the hypothesis that intravenous morphine increases serotonin (5‐HT) release within the rostral ventromedial medulla (RVM). We also injected morphine into various sites along the rostrocaudal extent of the periaqueductal gray (PAG), and examined the extent of its diffusion to the RVM. Intravenous morphine (3.0 mg/kg) produced thermal antinociception and increased RVM dialysate 5‐HT, 5‐hydroxyindole acetic acid (5‐HIAA), and homovanillic acid (HVA) in a naloxone‐reversible manner. As neither PAG microinjection of morphine (5 µg/0.5 µL) nor RVM administration of fentanyl ord‐Ala(2),NMePhe(4),Gly‐ol(5)]enkephalin (DAMGO) increased RVM 5‐HT, we were unable to determine the precise site of action of morphine. Surprisingly, peak morphine levels in the RVM were higher after microinjection into the caudal PAG as compared to either intravenous injection or microinjection into more rostral sites within the PAG. Naloxone‐precipitated withdrawal in morphine‐tolerant rats not only increased extracellular 5‐HT in the RVM, but also dopamine (DA) and HVA. We conclude that substantial amounts of morphine diffuse from the PAG to the RVM, and speculate that opioid receptor interactions at multiple brain sites mediate the analgesic effects of PAG morphine. Further studies will be required to elucidate the contribution of 5‐HT and DA release in the RVM to opioid analgesia and opioid withdrawal.
Regulation of brain mitochondrial H2O2 production by membrane potential and NAD(P)H redox state
Authors: Starkov Anatoly A. , Fiskum Gary 
Published: July 2010

AbstractMitochondrial production of reactive oxygen species (ROS) at Complex I of the electron transport chain is implicated in the etiology of neural cell death in acute and chronic neurodegenerative disorders. However, little is known regarding the regulation of mitochondrial ROS production by NADH‐linked respiratory substrates under physiologically realistic conditions in the absence of respiratory chain inhibitors. This study used Amplex Red fluorescence measurements of H2O2 to test the hypothesis that ROS production by isolated brain mitochondria is regulated by membrane potential (ΔΨ) and NAD(P)H redox state. ΔΨ was monitored by following the medium concentration of the lipophilic cation tetraphenylphosphonium with a selective electrode. NAD(P)H autofluorescence was used to monitor NAD(P)H redox state. While the rate of H2O2 production was closely related to ΔΨ and the level of NAD(P)H reduction at high values of ΔΨ, 30% of the maximal rate of H2O2 formation was still observed in the presence of uncoupler (p‐trifluoromethoxycarbonylcyanide phenylhydrazone) concentrations that provided for maximum depolarization of ΔΨ and oxidation of NAD(P)H. Our findings indicate that ROS production by mitochondria oxidizing physiological NADH‐dependent substrates is regulated by ΔΨ and by the NAD(P)H redox state over ranges consistent with those that exist at different levels of cellular energy demand.
Neuromelanin associated redox‐active iron is increased in the substantia nigra of patients with Parkinson's disease
Authors: Faucheux Baptiste A. , Martin Marie‐Elise , Beaumont Carole , Hauw Jean‐Jacques , Agid Yves , Hirsch Etienne C. 
Published: July 2010

AbstractDegeneration of dopaminergic neurones during Parkinson's disease is most extensive in the subpopulation of melanized‐neurones located in the substantia nigra pars compacta. Neuromelanin is a dark pigment produced in the dopaminergic neurones of the human substantia nigra and has the ability to bind a variety of metal ions, especially iron. Post‐mortem analyses of the human brain have established that oxidative stress and iron content are enhanced in association with neuronal death. As redox‐active iron (free Fe2+ form) and other transition metals have the ability to generate highly reactive hydroxyl radicals by a catalytic process, we investigated the redox activity of neuromelanin (NM)‐aggregates in a group of parkinsonian patients, who presented a statistically significant reduction (− 70%) in the number of melanized‐neurones and an increased non‐heme (Fe3+) iron content as compared with a group of matched‐control subjects. The level of redox activity detected in neuromelanin‐aggregates was significantly increased (+ 69%) in parkinsonian patients and was highest in patients with the most severe neuronal loss. This change was not observed in tissue in the immediate vicinity of melanized‐neurones. A possible consequence of an overloading of neuromelanin with redox‐active elements is an increased contribution to oxidative stress and intraneuronal damage in patients with Parkinson's disease.
A new G protein‐coupled receptor from a primitive metazoan shows homology with vertebrate aminergic receptors and displays constitutive activity in mammalian cells
Authors: Bouchard Christelle , Ribeiro Paula , Dubé François , Anctil Michel 
Published: July 2010

AbstractBiogenic amine receptors mediate wide‐ranging hormonal and modulatory functions in vertebrates, but are largely unknown in primitive invertebrates. In a representative of the most basal multicellular animals possessing a nervous system, the cnidarianRenilla koellikeri, aminergic‐like receptors were previously characterized pharmacologically and found to engender control of the animal's bioluminescent and peristaltic reactions. Using degenerate oligonucleotides in a RT‐PCR strategy, we obtained a full‐length cDNA encoding a polypeptide with typical G protein‐coupled receptor (GPCR) characteristics and which displayed a significant degree of sequence similarity (up to 45%) to biogenic amine receptors, particularly dopamine and adrenergic receptors. The new receptor, named Ren1, did not resemble any one specific type of amine GPCR and thus could not be identified on the basis of sequence. Ren1 was expressed transiently and stably in cultured mammalian cells, as demonstrated by immunocytochemistry and western blotting. Functional analysis of transfected HEK293, LTK‐ and COS‐7 cells, based on both cAMP and Ca2+signalling assays, revealed that Ren1 was not activated by any of the known biogenic amines tested and several related metabolites. The results indicated, however, that cells stably expressing Ren1 contained, on average, an 11‐fold higher level of cAMP than the controls, in the absence of agonist stimulation. The high basal cAMP levels were shown to be specific for Ren1 and to vary proportionally with the level of Ren1 expressed in the transfected cells. Taken together, the data suggested that Ren1 was expressed as a constitutively active receptor. Its identification provides a basis for examination of the early evolutionary emergence of GPCRs and their functional properties.
Cytochrome P450‐dependent metabolism ofl‐deprenyl in monkey (Cercopithecus aethiops) and C57BL/6 mouse brain microsomal preparations
Authors: Stefania Dragoni , Lydia Bellik , Maria Frosini , Giacomo Matteucci , Giampietro Sgaragli , Massimo Valoti 
Published: July 2010

AbstractThe aim of the present investigation was to characterize the cytochrome P450 (CYP)‐dependent metabolism ofl‐deprenyl by brain microsomal preparations obtained from two different animal models that have been extensively used in Parkinson's disease studies, namely monkey (Cercopithecus aethiops) and C57BL/6 mouse. In monkey brain microsomal fractions, the apparentKmvalues for methamphetamine formation froml‐deprenyl were 67.8 ± 1.0 and 72.0 ± 1.6 μm, in the cortex and striatum, respectively. Similarly, for nordeprenyl formation froml‐deprenyl,Kmvalues in cortex and striatum were 21.3 ± 3.2 and 27.3 ± 4.0 μm, respectively. Both metabolic pathways appear to be more efficient in the cortex than in the striatum as theVmaxfor microsomal preparation was lower in the striatum for the formation of both metabolites. The formation rate ofl‐methamphetamine was up to one order of magnitude greater than that of nordeprenyl. Inhibition analysis of both pathways in monkey brain suggested thatl‐methamphetamine formation is catalysed by CYP2A and CYP3A, whereas only CYP3A appears to be involved in nordeprenyl formation. With microsomal preparations from whole brain of C57BL/6 mice, the onlyl‐deprenyl metabolite that could be detected was methamphetamine and theKmandVmaxvalues were similar to those determined in monkey cortex (53.6 ± 2.9 μmand 33.9 ± 0.4 pmol/min/mg protein, respectively). 4‐Methylpyrazole selectively inhibited methamphetamine formation, suggesting the involvement of CYP2E1. In conclusion, the present study indicates thatl‐deprenyl is effectively metabolised by CYP‐dependent oxidases in the brain, giving rise mainly to the formation of methamphetamine, which has been suggested to play a role in the pharmacological effects of the parent drug. The results also demonstrate that there are differences between species in CYP‐dependent metabolism ofl‐deprenyl.
Green tea polyphenols enhance sodium nitroprusside‐induced neurotoxicity in human neuroblastoma SH‐SY5Y cells
Authors: Zhang Yueting , Zhao Baolu 
Published: July 2010

AbstractOxidative stress is a main mediator in nitric oxide (NO) ‐induced neurotoxicity and has been implicated in the pathogenesis of many neurodegenerative disorders. Green tea polyphenols are usually expected as potent chemo‐preventive agents due to their ability of scavenging free radicals and chelating metal ions. However, not all the actions of green tea polyphenols are necessarily beneficial. In the present study, we demonstrated that higher‐concentration green tea ployphenols significantly enhanced the neurotoxicity by treatment of sodium nitroprusside (SNP), a nitric oxide donor. SNP induced apoptosis in human neuroblastoma SH‐SY5Y cells in a concentration and time‐dependent manner, as estimated by cell viability assessment, FACScan analysis and DNA fragmentation assay, whereas treatment with green tea polyphenols alone had no effect on cell viability. Pre‐treatment with lower‐dose green tea polyphenols (50 and 100 μm) had only a slightly deleterious effect in the presence of SNP, while higher‐dose green tea polyphenols (200 and 500 μm) synergistically damaged the cells severely. Further research showed that co‐incubation of green tea polyphenols and SNP caused loss of mitochondrial membrane potential, depletion of intracellular GSH and accumulation of reactive oxygen species, and exacerbated NO‐induced neuronal apoptosis via a Bcl‐2 sensitive pathway.