1,922 research outputs found

    Stimulatory Effect of 5-Hydroxytryptamine (5-HT) on Rat Capsaicin-Sensitive Lung Vagal Sensory Neurons via Activation of 5-HT\u3csub\u3e3\u3c/sub\u3e Receptors

    Get PDF
    5-hydroxytryptamine (5-HT) is an inflammatory mediator known to be released in lung. Capsaicin-sensitive lung vagal (CSLV) afferents function as a primary sensor for detecting chemical stimuli and produce consequent reflexes during lung inflammation. To characterize the effect of 5-HT on CSLV afferents, responses of cardiorespiratory reflexes and single-unit C-fiber afferents to right-atrial injections of 5-HT were investigated in anesthetized Sprague-Dawley rats. Bolus injection of 5-HT (8 ÎĽg/kg) caused an immediate augmented breath and apnea, accompanied by hypotension and bradycardia. These initial responses were then followed by a brief pressor response and a more sustained depressor response. After a perineural treatment of both cervical vagi with capsaicin to block the conduction of C fibers, 5-HT still triggered the augmented breath, but no longer evoked the apnea, bradycardia and hypotension, indicating an involvement of C-fiber activation. The remaining augmented breath induced by 5-HT after perineural capsaicin treatment was totally eliminated by vagotomy. To further study the effect of 5-HT on CSLV afferents, activities arising from these afferents were determined using the single-fiber recording technique. Right-atrial injection of 5-HT evoked an intense discharge in CSLV afferents in a dose-dependent manner. The highest dose of 5-HT (16 ÎĽg/kg) activated 79% (19/24) of CSLV afferents which were also sensitive to capsaicin (0.8 ÎĽg/kg). The pretreatment of tropisetron, a selective antagonist of the 5-HT3 receptor, completely blocked CSLV-afferents stimulation induced by 5-HT but did not affect that by capsaicin. Furthermore, a similar afferent response of CSLV afferents was mimicked by phenylbiguanide, a selective agonist of the 5-HT3 receptor. In isolated rat lung vagal C neurons, 5-HT induced intense calcium transients in a dose-dependent manner. The highest concentration (3 ÎĽM) of 5-HT activated 67% (18/27) of the CSLV neurons. The 5-HT-induced response was totally abolished by pretreatment of tropisetron. In conclusion, 5-HT exerts an intense stimulatory effect on lung C-fiber terminals mediated through an activation of the 5-HT3 receptor, which may contribute to the airway hypersensitivity under lung inflammation

    An fMRI Study on How Descriptions of Supra-Natural Events Entertain and Enchant

    Get PDF
    Literature containing supra-natural, or magical events has enchanted generations of readers. When reading narratives describing such events, readers mentally simulate a text world different from the real one. The corresponding violation of world-knowledge during this simulation likely increases cognitive processing demands for ongoing discourse integration, catches readers’ attention, and might thus contribute to the pleasure and deep emotional experience associated with ludic immersive reading. In the present study, we presented participants in an MR scanner with passages selected fromthe Harry Potter book series, half of which described magical events, while the other half served as control condition. Passages in both conditions were closely matched for relevant psycholinguistic variables including, e.g., emotional valence and arousal, passage-wise mean word imageability and frequency, and syntactic complexity. Post-hoc ratings showed that readers considered supra-natural contents more surprising and more strongly associated with reading pleasure than control passages. In the fMRI data, we found stronger neural activation for the supra-natural than the control condition in bilateral inferior frontal gyri, bilateral inferior parietal lobules, left fusiformgyrus, and left amygdala. The increased activation in the amygdala (part of the salience and emotion processing network) appears to be associated with feelings of surprise and the reading pleasure, which supra-natural events, full of novelty and unexpectedness, brought about. The involvement of bilateral inferior frontal gyri likely reflects higher cognitive processing demand due to world knowledge violations, whereas increased attention to supra-natural events is reflected in inferior frontal gyri and inferior parietal lobules that are part of the fronto-parietal attention network

    Signal Amplification Assisted by Multiple Sideband Interference in 1D Waveguide QED Systems

    Full text link
    This study theoretically investigates signal amplification resulting from multiple Rabi sideband coherence in a one-dimensional waveguide quantum electrodynamical system. Specifically, we explore the behavior of a transmon while strongly driven by a coherent microwave field through a semi-infinite waveguide. To understand the underlying mechanisms of amplification, we develop a theory that explicitly takes into account multiple dressed sidebands under a strong driving field, and analyze the reflection amplitude of the probe signal. Our findings show that amplification can be related to either population inversion or multiple sideband constructive interference in some cases without population inversion. We further examine the effect of qubit dephasing during the amplification process

    International Students’ Perceptions of Service Quality in the UK Banking Sector: An Exploratory Study

    Get PDF
    This study reviews and evaluates international students’ perceptions of UK banks. The specific research objectives were to identify international students’ expectations and perceptions of service quality from UK banks and to assess the quality GAP or dissonance between these. A total of 297 international students studying in the UK responded to the survey. Data gathered was analyzed using Statistical Package for the Social Sciences (SPSS 16). The study reveals that the main areas of service quality with which international students are generally satisfied relates to tangibles such as physical layout and appearance. The key areas of dissatisfaction that the study identified were with factors related to reliability and empathy. This appears to be the first study in the UK banking sector that has focused on service quality with respect to international students
    • …
    corecore