Browsing by Subject "Inhibition"

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  • Ludwig, Anastasia; Rivera Baeza, Claudio; Uvarov, Pavel (2017)
    Background: Cation-chloride cotransporters (CCCs) are indispensable for maintaining chloride homeostasis in multiple cell types, but K-Cl cotransporter KCC2 is the only CCC member with an exclusively neuronal expression in mammals. KCC2 is critical for rendering fast hyperpolarizing responses of ionotropic.-aminobutyric acid and glycine receptors in adult neurons, for neuronal migration in the developing central nervous system, and for the formation and maintenance of small dendritic protrusions-dendritic spines. Deficit in KCC2 expression and/or activity is associated with epilepsy and neuropathic pain, and effective strategies are required to search for novel drugs augmenting KCC2 function. Results: We revised current methods to develop a noninvasive optical approach for assessing KCC2 transport activity using a previously characterized genetically encoded chloride sensor. Our protocol directly assesses dynamics of KCC2-mediated chloride efflux and allows measuring genuine KCC2 activity with good spatial and temporal resolution. As a proof of concept, we used this approach to compare transport activities of the two known KCC2 splice isoforms, KCC2a and KCC2b, in mouse neuronal Neuro-2a cells. Conclusions: Our noninvasive optical protocol proved to be efficient for assessment of furosemide-sensitive chloride fluxes. Transport activities of the N-terminal splice isoforms KCC2a and KCC2b obtained by the novel approach matched to those reported previously using standard methods for measuring chloride fluxes.
  • Ludwig, Anastasia; Rivera, Claudio; Uvarov, Pavel (BioMed Central, 2017)
    Abstract Background Cation-chloride cotransporters (CCCs) are indispensable for maintaining chloride homeostasis in multiple cell types, but K–Cl cotransporter KCC2 is the only CCC member with an exclusively neuronal expression in mammals. KCC2 is critical for rendering fast hyperpolarizing responses of ionotropic γ-aminobutyric acid and glycine receptors in adult neurons, for neuronal migration in the developing central nervous system, and for the formation and maintenance of small dendritic protrusions—dendritic spines. Deficit in KCC2 expression and/or activity is associated with epilepsy and neuropathic pain, and effective strategies are required to search for novel drugs augmenting KCC2 function. Results We revised current methods to develop a noninvasive optical approach for assessing KCC2 transport activity using a previously characterized genetically encoded chloride sensor. Our protocol directly assesses dynamics of KCC2-mediated chloride efflux and allows measuring genuine KCC2 activity with good spatial and temporal resolution. As a proof of concept, we used this approach to compare transport activities of the two known KCC2 splice isoforms, KCC2a and KCC2b, in mouse neuronal Neuro-2a cells. Conclusions Our noninvasive optical protocol proved to be efficient for assessment of furosemide-sensitive chloride fluxes. Transport activities of the N-terminal splice isoforms KCC2a and KCC2b obtained by the novel approach matched to those reported previously using standard methods for measuring chloride fluxes.
  • Rahikainen, Anna-Liina; Palo, Jukka U.; de Leeuw, Wiljo; Budowle, Bruce; Sajantila, Antti (2016)
    Blood samples preserved on FTA cards offer unique opportunities for genetic research. DNA recovered from these cards should be stable for long periods of time. However, it is not well established as how well the DNA stored on FTA card for substantial time periods meets the demands of forensic or genomic DNA analyses and especially so for from post-mortem (PM) samples in which the quality can vary upon initial collection. The aim of this study was to evaluate the time-dependent degradation on DNA quality and quantity extracted from up to 16 years old post-mortem bloodstained FTA cards. Four random FTA samples from eight time points spanning 1998 to 2013 (n = 32) were collected and extracted in triplicate. The quantity and quality of the extracted DNA samples were determined with Quantifiler (R) Human Plus (HP) Quantification kit. Internal sample and sample-to-sample variation were evaluated by comparing recovered DNA yields. The DNA from the triplicate samplings were subsequently combined and normalized for further analysis. The practical effect of degradation on DNA quality was evaluated from normalized samples both with forensic and pharmacogenetic target markers. Our results suggest that (1) a PM change, e.g. blood clotting prior to sampling, affects the recovered DNA yield, creating both internal and sample-to-sample variation; (2) a negative correlation between the FTA card storage time and DNA quantity (r = -0.836 at the 0.01 level) was observed; (3) a positive correlation (r = 0.738 at the level 0.01) was found between FTA card storage time and degradation levels. However, no inhibition was observed with the method used. The effect of degradation was manifested clearly with functional applications. Although complete STR-profiles were obtained for all samples, there was evidence of degradation manifested as decreased peak heights in the larger-sized amplicons. Lower amplification success was notable with the large 5.1 kb CYP2D6 gene fragment which strongly supports degradation of the stored samples. According to our results, DNA stored on FTA cards is rather stable over a long time period. DNA extracted from this storage medium can be used as human identification purposes as the method used is sufficiently sensitive and amplicon sizes tend to be <400 bp. However, DNA integrity was affected during storage. This effect should be taken into account depending on the intended application especially if high quality DNA and long PCR amplicons are required. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
  • Suzuki, Kota; Kita, Yosuke; Shirakawa, Yuka; Egashira, Yuka; Mitsuhashi, Shota; Kitamura, Yuzuki; Okuzumi, Hideyuki; Kaga, Yoshimi; Inagaki, Masumi (2020)
    Nogo-N2 is associated with the premotor cognitive process that precedes motor response (e.g., conflict monitoring), whereas Nogo-P3 is related to the inhibition of the actual motor response. We examined the influence of motor clumsiness of developmental coordination disorder (DCD) on components of the event-related potential in a Go/Nogo task. Participants were healthy adults (N = 81) that were classified into control and DCD groups based on the Movement Assessment Battery for Children Second Edition. We manipulated the difficulty in stopping a response by varying the frequency of Nogo stimuli in a response task into rare (20%) and frequent (80%) conditions, and Nogo-N2 and Nogo-P3 were calculated from electroencephalograms (EEGs) during the Go/Nogo tasks. The commission error rate in the rare condition was significantly higher in the DCD group than in the control group, indicating that motor clumsiness decreases task performance. There were no differences in Nogo-N2 between DCD and control groups. However, Nogo-P3 in the rare condition was reduced in the DCD group compared to the control group. These results suggest that the influence of motor clumsiness is limited to the cognitive process after the initiation of the actual motor response.
  • Viljaranta, Jaana; Aunola, Kaisa; Mullola, Sari; Luonua, Marjaana; Tuomas, Anne; Nurmi, Jan-Erik (2020)
    It has repeatedly been found that temperamental inhibition and low academic achievement are associated with each other: children with cautious and wary or shy behaviour are at risk for low academic achievement. Several suggestions about the mechanism behind this association have been made, these highlighting for example, the fewer learning opportunities of cautious and wary children and more negative interaction between teachers and inhibited children. However, the empirical studies about these mechanisms are rare and, thus, they have remained unclear. This study examined whether children's maths-related self-concept of ability acts as a mediator between their temperamental inhibition and maths performance. 156 children (M-age 7.25 years) were followed during the first grade of primary school. Children's temperamental inhibition was assessed in the beginning of Grade 1. Their maths performance was tested twice, in the beginning and at the end of Grade 1, and their self-concept of ability was measured at the end of Grade 1. The research question was analysed using structural equation modelling. The results showed that children's self-concept of ability did mediate the association between temperamental inhibition and maths performance at Grade 1: that more inhibited children feel they are less capable and competent in maths than less inhibited children, and this contributes to their poorer maths performance. The findings highlight that it is important for teachers and other practitioners to be aware of this effect of temperamental inhibition on self-concept and put effort on promoting positive views of children's competencies and abilities.