bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensory gating in primary insomnia
Authors: Hairston Ilana S. , Talbot Lisa S. , Eidelman Polina , Gruber June , Harvey Allison G. 
Published: June 2010

AbstractAlthough previous research indicates that sleep architecture is largely intact in primary insomnia (PI), the spectral content of the sleeping electroencephalographic trace and measures of brain metabolism suggest that individuals with PI are physiologically more aroused than good sleepers. Such observations imply that individuals with PI may not experience the full deactivation of sensory and cognitive processing, resulting in reduced filtering of external sensory information during sleep. To test this hypothesis, gating of sensory information during sleep was tested in participants with primary insomnia (n = 18) and good sleepers (n = 20). Sensory gating was operationally defined as (i) the difference in magnitude of evoked response potentials elicited by pairs of clicks presented during Wake and Stage II sleep, and (ii) the number of K complexes evoked by the same auditory stimulus. During wake the groups did not differ in magnitude of sensory gating. During sleep, sensory gating of the N350 component was attenuated and completely diminished in participants with insomnia. P450, which occurred only during sleep, was strongly gated in good sleepers, and less so in participants with insomnia. Additionally, participants with insomnia showed no stimulus‐related increase in K complexes. Thus, PI is potentially associated with impaired capacity to filter out external sensory information, especially during sleep. The potential of using stimulus‐evoked K complexes as a biomarker for primary insomnia is discussed.
The kisspeptin system of the human hypothalamus: sexual dimorphism and relationship with gonadotropin‐releasing hormone and neurokinin B neurons
Authors: Hrabovszky E. , Ciofi P. , Vida B. , Horvath M. C. , Keller E. , Caraty A. , Bloom S. R. , Ghatei M. A. , Dhillo W. S. , Liposits Z. , Kallo I. 
Published: June 2010

AbstractKisspeptin signaling via the kisspeptin receptor G‐protein‐coupled receptor‐54 plays a fundamental role in the onset of puberty and the regulation of mammalian reproduction. In this immunocytochemical study we addressed the (i) topography, (ii) sexual dimorphism, (iii) relationship to gonadotropin‐releasing hormone (GnRH) neurons and (iv) neurokinin B content of kisspeptin‐immunoreactive hypothalamic neurons in human autopsy samples. In females, kisspeptin‐immunoreactive axons formed a dense periventricular plexus and profusely innervated capillary vessels in the infundibular stalk. Most immunolabeled somata occurred in the infundibular nucleus. Many cells were also embedded in the periventricular fiber plexus. Rostrally, they formed a prominent periventricular cell mass (magnocellular paraventricular nucleus). Robust sex differences were noticed in that fibers and somata were significantly less numerous in male individuals. In dual‐immunolabeled specimens, fine kisspeptin‐immunoreactive axon varicosities formed axo‐somatic, axo‐dendritic and axo‐axonal contacts with GnRH neurons. Dual‐immunofluorescent studies established that 77% of kisspeptin‐immunoreactive cells in the infundibular nucleus synthesize the tachykinin peptide neurokinin B, which is known to play crucial role in human fertility; 56 and 17% of kisspeptin fibers in the infundibular and periventricular nuclei, respectively, contained neurokinin B immunoreactivity. Site‐specific co‐localization patterns implied that kisspeptin neurons in the infundibular nucleus and elsewhere contributed differentially to these plexuses. This study describes the distribution and robust sexual dimorphism of kisspeptin‐immunoreactive elements in human hypothalami, reveals neuronal contacts between kisspeptin‐immunoreactive fibers and GnRH cells, and demonstrates co‐synthesis of kisspeptins and neurokinin B in the infundibular nucleus. The neuroanatomical information will contribute to our understanding of central mechanisms whereby kisspeptins regulate human fertility.
The histaminergic tuberomammillary nucleus is critical for motivated arousal
Authors: Valdés José Luis , Sánchez Cristián , Riveros María Eugenia , Blandina Patrizio , Contreras Marco , Farías Paula , Torrealba Fernando 
Published: June 2010

AbstractObtaining food, shelter or water, or finding a mating partner are examples of motivated behaviors, which are essential to preserve the species. The full expression of such behaviors requires a high but optimal arousal state. We tested the idea that tuberomammillary nucleus (TMN) histamine neurons are crucial to generate such motivated arousal, using a model of the appetitive phase of feeding behavior. Hungry rats enticed with food within a wire mesh box showed intense goal‐directed motor activity aimed at opening the box, an increase in core temperature, a fast histamine release in the hypothalamus and an early increase in Fos immunoreactivity in TMN and cortical neurons. Enticing with stronger‐tasting food induced stronger motor, temperature and Fos immunoreactivity brain responses than ordinary food pellets. TMN lesion greatly decreased all of those responses. We conclude that histamine neurons increase arousal and vegetative activity, allowing the normal unfolding of voluntary, goal‐directed behavior such as obtaining food.
Abundance and diversity of heterotrophic bacterial cells assimilating phosphate in the subtropical North Atlantic Ocean
Authors: Longnecker Krista , Lomas Michael W. , Van Mooy Benjamin A. S. 
Published: June 2010

SummaryMicroorganisms play key roles in the cycles of carbon and nutrients in the ocean, and identifying the extent to which specific taxa contribute to these cycles will establish their ecological function. We examined the use of 33P‐phosphate to identify heterotrophic bacteria actively involved in the cycling of phosphate, an essential inorganic nutrient. Seawater from the sub‐tropical North Atlantic Ocean was incubated with 33P‐phosphate and analysed by microautoradiography to determine the proportion and diversity of the bacterial community‐assimilating phosphate. Complementary incubations using 3H‐leucine and 3H‐thymidine were also conducted. We found that a higher proportion of total heterotrophic bacterial cells in surface water samples assimilated phosphate compared with leucine or thymidine. Bacteria from all of the phylogenetic groups we identified by CARD‐FISH were able to assimilate phosphate, although the abundances of cells within each group did not scale directly with the number found to assimilate phosphate. Furthermore, a significantly higher proportion of Alphaproteobacteria, Gammaproteobacteria and Cytophaga‐like cells assimilated phosphate compared with leucine or thymidine. Our results suggest that a greater proportion of bacterial cells in surface waters are actively participating in the biogeochemical cycling of phosphorus, and possibly other elements, than is currently estimated through the use of 3H‐leucine or 3H‐thymidine.
Strong effects of amoebae grazing on the biomass and genetic structure of a Microcystis bloom (Cyanobacteria)
Authors: Van Wichelen Jeroen , Van Gremberghe Ineke , Vanormelingen Pieter , Debeer Ann‐Eline , Leporcq Bruno , Menzel Diana , Codd Geoffrey A. , Descy Jean‐Pierre , Vyverman Wim 
Published: June 2010

SummaryDespite its importance for bloom toxicity, the factors determining the population structure of cyanobacterial blooms are poorly understood. Here, we report the results of a two‐year field survey of the population dynamics of Microcystis blooms in a small hypertrophic urban pond. Microscopic enumeration of Microcystis and its predators and parasites was combined with pigment and microcystin analysis and denaturing gradient gel electrophoresis of the ITS rDNA region to assess population dynamics and structure. Two main Microcystis morpho‐ and ITS types were revealed, corresponding to M. aeruginosa and M. viridis. In both years, high population densities of naked amoebae grazing on Microcystis coincided with rapid decreases in Microcystis biomass. In one year, there was a shift from heavily infested M. aeruginosa to the less‐infested M. viridis, allowing the bloom to rapidly recover. The preference of amoebae for M. aeruginosa was confirmed by grazing experiments, in which several amoeba strains were capable of grazing down a strain of M. aeruginosa, but not of M. viridis. Zooplankton and chytrid parasites appeared to be of minor importance for these strong and fast reductions in Microcystis biomass. These findings demonstrate a strong impact of small protozoan grazers on the biomass and genetic structure of Microcystis blooms.
Natural transformation of Vibrio fischeri requires tfoX and tfoY
Authors: Pollack‐Berti Amber , Wollenberg Michael S. , Ruby Edward G. 
Published: June 2010

SummaryRecent evidence has indicated that natural genetic transformation occurs in Vibrio cholerae, and that it requires both induction by chitin oligosaccharides, like chitohexaose, and expression of a putative regulatory gene designated tfoX. Using sequence and phylogenetic analyses we have found two tfoX paralogues in all sequenced genomes of the genus Vibrio. Like V. cholerae, when grown in chitohexaose, cells of V. fischeri are able to take up and incorporate exogenous DNA. Chitohexaose‐independent transformation by V. fischeri was observed when tfoX was present in multicopy. The second tfoX paralogue, designated tfoY, is also required for efficient transformation in V. fischeri, but is not functionally identical to tfoX. Natural transformation of V. fischeri facilitates rapid transfer of mutations across strains, and provides a highly useful tool for experimental genetic manipulation in this species. The presence of chitin‐induced competence in several vibrios highlights the potential for a conserved mechanism of genetic exchange across this family of environmentally important marine bacteria.
Sigh rate and respiratory variability during mental load and sustained attention
Authors: Vlemincx Elke , Taelman Joachim , De Peuter Steven , Van Diest Ilse , Van Den Bergh Omer 
Published: June 2010

AbstractSpontaneous breathing consists of substantial correlated variability: Parameters characterizing a breath are correlated with parameters characterizing previous and future breaths. On the basis of dynamic system theory, negative emotion states are predicted to reduce correlated variability whereas sustained attention is expected to reduce total respiratory variability. Both are predicted to evoke sighing. To test this, respiratory variability and sighing were assessed during a baseline, stressful mental arithmetic task, nonstressful sustained attention task, and recovery in between tasks. For respiration rate (excluding sighs), reduced total variability was found during the attention task, whereas correlated variation was reduced during mental load. Sigh rate increased during mental load and during recovery from the attention task. It is concluded that mental load and task‐related attention show specific patterns in respiratory variability and sigh rate.
Nurr1 regulates RET expression in dopamine neurons of adult rat midbrain
Authors: Galleguillos Danny , Fuentealba José A. , Gómez Luis M. , Saver Mathias , Gómez Andrea , Nash Kevin , Burger Corinna , Gysling Katia , Andrés María E. 
Published: June 2010

J. Neurochem. (2010) 114, 1158–1167.AbstractGenesis of midbrain dopamine (DA) neurons depends on Nurr1, a nuclear receptor expressed during development and adulthood in these neurons. Nurr1 is required for the expression of genes of dopaminergic phenotype such as tyrosine hydroxylase and DA transporter. The expression of the tyrosine kinase receptor RET also depends on Nurr1 during development. However, it is unknown whether RET expression is regulated by Nurr1 during adulthood, and the mechanism by which Nurr1 regulates RET expression. Using an adeno‐associated vector‐delivered anti‐Nurr1 ribozyme, we knocked‐down Nurr1 expression unilaterally in the substantia nigra (SN) of adult rats. Animals injected with the ribozyme displayed a 57.3% decrease in Nurr1 mRNA in the SN accompanied by decreased DA extracellular levels in the striatum. RET mRNA in the injected SN and RET protein in the ipsilateral striatum decreased 76.9% and 47%, respectively. Tyrosine hydroxylase and DA transporter mRNA did not change in Nurr1 knocked‐down SN. Nurr1 induced the transcription of the human RET promoter in cell type and concentration‐dependent manner. Nurr1 induction of RET promoter is independent of NBRE elements. These results show that the expression of RET in rat adult SN is regulated by Nurr1 and suggest that RET is a transcriptional target of this nuclear receptor.
Repeated administration of α7 nicotinic acetylcholine receptor (nAChR) agonists, but not positive allosteric modulators, increases α7 nAChR levels in the brain
Authors: Christensen Ditte Z. , Mikkelsen Jens D. , Hansen Henrik H. , Thomsen Morten S. 
Published: June 2010

J. Neurochem.(2010)114, 1205–1216.AbstractThe α7 nicotinic acetylcholine receptor (nAChR) is an important target for treatment of cognitive deficits in schizophrenia and Alzheimer’s disease. However, the receptor desensitizes rapidlyin vitro, which has led to concern regarding its applicability as a clinically relevant drug target. Here we investigate the effects of repeated agonism on α7 nAChR receptor levels and responsivenessin vivoin rats. Using [125I]‐α‐bungarotoxin (BTX) autoradiography we show that acute or repeated administration with the selective α7 nAChR agonist A‐582941 increases the number of α7 nAChR binding sites in several brain regions, particularly in the prefrontal cortex. The α7 nAChR agonists SSR180711 and PNU‐282987 also increase [125I]‐BTX binding, suggesting that this is a general consequence of α7 nAChR agonism. Interestingly, the α7 nAChR positive allosteric modulators PNU‐120596 and NS1738 do not increase [125I]‐BTX binding. Furthermore, A‐582941‐induced increase in Arc and c‐fosmRNA expression in the prefrontal cortex is enhanced and unaltered, respectively, after repeated administration, demonstrating that the α7 nAChRs remain responsive. Contrarily, A‐582941‐induced phosphorylation of Erk2 in the prefrontal cortex occurs following acute, but not repeated administration. Our results demonstrate that repeated agonist administration increases the number of α7 nAChRs in the brain, and leads to coupling versus uncoupling of specific intracellular signaling pathways. Additionally, our data suggest a fundamental difference between the sequelae of repeated administration with agonists and allosteric modulators of the α7 nAChR.
Simultaneous quantification of myocardial perfusion, oxidative metabolism, cardiac efficiency and pump function at rest and during supine bicycle exercise using 1‐11C‐acetate PET – a pilot study
Authors: Sörensen Jens , Valind Sven , Andersson Lars G. 
Published: June 2010

SummaryBackground:  PET using 1‐11C‐acetate (ACE‐PET) applied at rest is used for measuring absolute myocardial blood flow (MBF) and oxidative metabolic rate (kmono). We evaluated the feasibility of quantitative ACE‐PET during exercise.Methods:  Five endurance athletes underwent dynamic PET scanning at rest and during supine bicycle stress. Exercise was maintained at a workload of 120 Watt for 17 min. The rate‐pressure product (RPP) was recorded repeatedly. MBF, kmono in left (LV) and right (RV) ventricular wall, cardiac output (CO), cardiac efficiency and a lung uptake value reflecting left heart diastolic pressures were calculated from the PET data using previously validated models.Results:  MBF increased from 0·71 ± 0·17 to 2·48 ± 0·25 ml min−1 per ml, LV‐kmono from 0·050 ± 0·005 to 0·146 ± 0·021 min−1, RV‐kmono from 0·023 + 0·006 to 0·087 + 0·014 min‐1, RPP from 4·7 ± 0·8 to 13·2 ± 1·4 mmHg × min−1 × 103 and Cardiac Output from 5·2 ± 1·1 to 12·3 ± 1·2 l min −1 (all P < 0·001). Cardiac efficiency was unchanged (P = 0·99). Lung uptake decreased from 1·1 ± 0·2 to 0·6 ± 0·1 ml g−1 (P < 0·001).Discussion:  A number of important parameters related to cardiac function can be quantified non‐invasively and simultaneously with a short scanning protocol during steady state supine bicycling. This might open up new opportunities for studies of the integrated cardiac physiology in health and early asymptomatic disease.
Assessment of anaerobic power to verify VO2max attainment
Authors: Astorino Todd A. , White Ailish C. 
Published: June 2010

SummaryAcross various populations, verification testing is used to confirm VO2max attainment and has repeatedly shown similar VO2max values to those obtained from incremental exercise. Yet, many individuals show meaningful differences in VO2max between protocols, and an explanation for this is unknown. The aim of the study was to elucidate this phenomenon in 30 men and women of similar age, fitness, and physical activity using assessment of anaerobic power. On day 1, they completed the Wingate test, and returned at least 48 h later to complete incremental cycle ergometry followed by a verification protocol. During exercise, ventilation, pulmonary gas exchange data, and heart rate (HR) were continuously measured. Mean VO2max was similar (P > 0·05) between protocols (42·05 ± 5·88 ml kg−1 per min versus 42·03 ± 5·75 ml kg−1 per min, respectively), although seven subjects (23%) revealed a VO2max that was not ‘verified’ by the supramaximal protocol. Indices of power output and gas exchange data were similar (P > 0·05) between subjects who revealed a ‘true’ VO2max compared to those who did not, although peak and mean power was consistently higher in persons whose VO2max was not ‘verified.’ A previously established HRmax criterion for verification testing was not met in 17% of subjects. Additional study is merited to identify alternate determinants of VO2max, such as muscle activation via assessment of motor unit recruitment, and to investigate utility of verification testing to confirm VO2max attainment in elite athletes and the elderly.
Induction of a novel cation current in cardiac ventricular myocytes by flufenamic acid and related drugs
Authors: Macianskiene R , Gwanyanya A , Sipido KR , Vereecke J , Mubagwa K 
Published: June 2010

BACKGROUND AND PURPOSEInterest in non‐selective cation channels has increased recently following the discovery of transient receptor potential (TRP) proteins, which constitute many of these channels.EXPERIMENTAL APPROACHWe used the whole‐cell patch‐clamp technique on isolated ventricular myocytes to investigate the effect of flufenamic acid (FFA) and related drugs on membrane ion currents.KEY RESULTSWith voltage‐dependent and other ion channels inhibited, cells that were exposed to FFA, N‐(p‐amylcinnamoyl)anthranilic acid (ACA), ONO‐RS‐082 or niflumic acid (NFA) responded with an increase in currents. The induced current reversed at +38 mV, was unaffected by lowering extracellular Cl‐concentration or by the removal of extracellular Ca2+and Mg2+, and its inward but not outward component was suppressed in Na+‐free extracellular conditions. The current was suppressed by Gd3+but was resistant to 2‐aminoethoxydiphenyl borate (2‐APB) and to amiloride. It could not be induced by the structurally related non‐fenamate anti‐inflammatory drug diclofenac, nor by the phospholipase‐A2inhibitors bromoenol lactone and bromophenacyl bromide. Muscarinic or α‐adrenoceptor activation or application of diacylglycerol failed to induce or modulate the current.CONCLUSIONS AND IMPLICATIONSFlufenamic acid and related drugs activate a novel channel conductance, where Na+is likely to be the major charge carrier. The identity of the channel remains unclear, but it is unlikely to be due to Ca2+‐activated (e.g. TRPM4/5), Mg2+‐sensitive (e.g. TRPM7) or divalent cation‐selective TRPs.
Reduced signal transduction by 5‐HT4receptors after long‐term venlafaxine treatment in rats
Authors: Vidal R , Valdizan EM , Vilaró MT , Pazos A , Castro E 
Published: June 2010

BACKGROUND AND PURPOSEThe 5‐HT4receptor may be a target for antidepressant drugs. Here we have examined the effects of the dual antidepressant, venlafaxine, on 5‐HT4receptor‐mediated signalling events.EXPERIMENTAL APPROACHThe effects of 21 days treatment (p.o.) with high (40 mg·kg−1) and low (10 mg·kg−1) doses of venlafaxine, were evaluated at different levels of 5‐HT4receptor‐mediated neurotransmission by usingin situhybridization, receptor autoradiography, adenylate cyclase assays and electrophysiological recordings in rat brain. The selective noradrenaline reuptake inhibitor, reboxetine (10 mg·kg−1, 21 days) was also evaluated on 5‐HT4receptor density.KEY RESULTSTreatment with a high dose (40 mg·kg−1) of venlafaxine did not alter 5‐HT4mRNA expression, but decreased the density of 5‐HT4receptors in caudate‐putamen (% reduction = 26 ± 6), hippocampus (% reduction = 39 ± 7 and 39 ± 8 for CA1 and CA3 respectively) and substantia nigra (% reduction = 49 ± 5). Zacopride‐stimulated adenylate cyclase activation was unaltered following low‐dose treatment (10 mg·kg−1) while it was attenuated in rats treated with 40 mg·kg−1of venlafaxine (% reduction = 51 ± 2). Furthermore, the amplitude of population spike in pyramidal cells of CA1 of hippocampus induced by zacopride was significantly attenuated in rats receiving either dose of venlafaxine. Chronic reboxetine did not modify 5‐HT4receptor density.CONCLUSIONS AND IMPLICATIONSOur data indicate a functional desensitization of 5‐HT4receptors after chronic venlafaxine, similar to that observed after treatment with the classical selective inhibitors of 5‐HT reuptake.
Post‐junctional interactions between neuromuscular blocking agents and ethanol at the mouse neuromuscular junction
Authors: Searl TJ , Silinsky EM 
Published: June 2010

BACKGROUND AND PURPOSEEthanol is known to have both pre‐synaptic and post‐synaptic effects at a range of loci in the mammalian nervous system, including the neuromuscular junction. However, the effects of ethanol on evoked synaptic transmission have not been previously studied at the mouse neuromuscular junction. Here, we report on the effects of ethanol on evoked neuromuscular transmission and the interaction of ethanol with non‐depolarizing blocking drugs.EXPERIMENTAL APPROACHElectrophysiological techniques to measure synaptic potentials and synaptic currents were employed in this study.KEY RESULTSEthanol (≥100 mM) produced increases in the amplitudes of both spontaneous and evoked synaptic events. Under conditions in which neuromuscular transmission was blocked by (+)‐tubocurarine, ethanol (12–100 mM) produced greater increases in evoked response amplitude than in spontaneous response amplitude recorded in the absence of (+)‐tubocurarine. Ethanol (100 mM) did not affect evoked neurotransmitter release in low‐calcium/high‐magnesium solutions. With respect to the clinically used neuromuscular blocking drugs, ethanol (100 mM) interfered with the blocking action of vecuronium, but not cisatracurium.CONCLUSIONS AND IMPLICATIONSUnder these conditions, the stimulant effect of ethanol on neuromuscular transmission is exclusively on the post‐junctional elements, both to enhance transmission through nicotinic receptors and also via interactions with neuromuscular blocking agents. These actions of ethanol on neuromuscular transmission may affect the dosage of neuromuscular blockers required in patients who have imbibed significant amounts of alcohol.