Quantitative reconstruction of a single super rainstorm using daily resolved δ18O of land snail shells.

A "once-in-a-millennium" super rainstorm battered Zhengzhou, central China, from 07/17/2021 to 07/22/2021 (named "7.20" Zhengzhou rainstorm). It killed 398 people and caused billions of dollars in damage. A pressing question is whether rainstorms of this intensity can be effectively documented by geological archives to understand better their historical variabilities beyond the range of meteorological data. Here, four land snail shells were collected from Zhengzhou, and weekly to daily resolved snail shell δ18O records from June to September of 2021 were obtained by gas-source mass spectrometry and secondary ion mass spectrometry. The daily resolved records show a dramatic negative shift between 06/18/2021 and 09/18/2021, which has been attributed to the "7.20" Zhengzhou rainstorm. Moreover, the measured amplitude of this shift is consistent with the theoretical value estimated from the flux balance model and instrumental data for the "7.20" Zhengzhou rainstorm. Our results suggest that the ultra-high resolution δ18O of land snail shells have the potential to reconstruct local synoptic scale rainstorms quantitatively, and thus fossil snail shells in sedimentary strata can be valuable material for investigating the historical variability of local rainstorms under different climate backgrounds.

Functional prediction of AMP deaminase 1 in Jingyuan chicken and evaluation of the biological activities of its expression vectors.

This study investigated the function of AMP deaminase 1 (AMPD1) in Jingyuan chicken and the biological activity of its expression vector. AMPD1 was cloned and sequenced from chicken breast muscle tissue by RT-PCR and further analyzed using Cluster, DNASTAR, and online bioinformatics software, as well as vector construction, qPCR, Western blotting, enzymatic digestion, and sequencing. The coding sequence was 2162 bp, encoding 683 amino acids and producing a protein of approximately 78.95 kDa. After verification, the overexpression plasmids pEGFP-AMPD1, Cas9/sgRNA2, and Cas9/sgRNA3 were found to have biological activity in chicken muscle cells and individual chickens, and two sgRNAs (sgRNA2, sgRNA3) were identified that could edit AMPD1. The qPCR and Western blotting result showed that the pEGFP-AMPD1 plasmid significantly increased both mRNA and protein expression of AMPD1. T7EI digestion showed editing efficiencies of approximately 35 %, 37 %, and 33 % for sgRNA2, sgRNA3, and sgRNA2 + sgRNA3 of AMPD1 in chicken muscle cells. In comparison, TA cloning sequencing showed editing efficiencies of approximately 36.7 %, 86.7 %, and 26.7 % and editing efficiencies in chicken individuals of approximately 71 %, 45 %, and 76.7 %, respectively. These results provide a theoretical basis and support for further investigation into the function of the AMPD1 gene.

Spontaneous brain activity in the hippocampal regions could characterize cognitive impairment in patients with Parkinson's disease.

OBJECTIVE: This study aimed to investigate whether spontaneous brain activity can be used as a prospective indicator to identify cognitive impairment in patients with Parkinson's disease (PD). METHODS: Resting-state functional magnetic resonance imaging (RS-fMRI) was performed on PD patients. The cognitive level of patients was assessed by the Montreal Cognitive Assessment (MoCA) scale. The fractional amplitude of low-frequency fluctuation (fALFF) was applied to measure the strength of spontaneous brain activity. Correlation analysis and between-group comparisons of fMRI data were conducted using Rest 1.8. By overlaying cognitively characterized brain regions and defining regions of interest (ROIs) based on their spatial distribution for subsequent cognitive stratification studies. RESULTS: A total of 58 PD patients were enrolled in this study. They were divided into three groups: normal cognition (NC) group (27 patients, average MoCA was 27.96), mild cognitive impairment (MCI) group (21 patients, average MoCA was 23.52), and severe cognitive impairment (SCI) group (10 patients, average MoCA was 17.3). It is noteworthy to mention that those within the SCI group exhibited the most advanced chronological age, with an average of 74.4 years, whereas the MCI group displayed a higher prevalence of male participants at 85.7%. It was found hippocampal regions were a stable representative brain region of cognition according to the correlation analysis between the fALFF of the whole brain and cognition, and the comparison of fALFF between different cognitive groups. The parahippocampal gyrus was the only region with statistically significant differences in fALFF among the three cognitive groups, and it was also the only brain region to identify MCI from NC, with an AUC of 0.673. The paracentral lobule, postcentral gyrus was the region that identified SCI from NC, with an AUC of 0.941. The midbrain, hippocampus, and parahippocampa gyrus was the region that identified SCI from MCI, with an AUC of 0.926. CONCLUSION: The parahippocampal gyrus was the potential brain region for recognizing cognitive impairment in PD, specifically for identifying MCI. Thus, the fALFF of parahippocampal gyrus is expected to contribute to future study as a multimodal fingerprint for early warning.

The Cambrian microfossil Qingjiangonema reveals the co-evolution of sulfate-reducing bacteria and the oxygenation of Earth's surface.

Sulfate reduction is an essential metabolism that maintains biogeochemical cycles in marine and terrestrial ecosystems. Sulfate reducers are exclusively prokaryotic, phylogenetically diverse, and may have evolved early in Earth's history. However, their origin is elusive and unequivocal fossils are lacking. Here we report a new microfossil, Qingjiangonema cambria, from ∼518-million-year-old black shales that yield the Qingjiang biota. Qingjiangonema is a long filamentous form comprising hundreds of cells filled by equimorphic and equidimensional pyrite microcrystals with a light sulfur isotope composition. Multiple lines of evidence indicate Qingjiangonema was a sulfate-reducing bacterium that exhibits similar patterns of cell organization to filamentous forms within the phylum Desulfobacterota, including the sulfate-reducing Desulfonema and sulfide-oxidizing cable bacteria. Phylogenomic analyses confirm separate, independent origins of multicellularity in Desulfonema and in cable bacteria. Molecular clock analyses infer that the Desulfobacterota, which encompass a majority of sulfate-reducing taxa, diverged ∼2.41 billion years ago during the Paleoproterozoic Great Oxygenation Event, while cable bacteria diverged ∼0.56 billion years ago during or immediately after the Neoproterozoic Oxygenation Event. Taken together, we interpret Qingjiangonema as a multicellular sulfate-reducing microfossil and propose that cable bacteria evolved from a multicellular filamentous sulfate-reducing ancestor. We infer that the diversification of the Desulfobacterota and the origin of cable bacteria may have been responses to oxygenation events in Earth's history.

Comparison of percutaneous balloon compression and microvascular decompression in the treatment of trigeminal neuralgia.

Objective: To compare the effect of percutaneous balloon compression (PBC) and microvascular decompression (MVD) in the treatment of trigeminal neuralgia (TN). Methods: Data of 98 patients with TN, admitted to Chenzhou First People's Hospital from May 2020 to May 2022, were retrospectively collected. Patients were divided into two groups based on the surgical method. A total of 53 patients treated with PBC comprised the PBC-group and 45 patients treated with MVD comprised the MVD-group. The immediate pain relief, long-term efficacy, surgical complications, and masticatory muscle strength of the two groups were compared and analyzed. Results: There was no significant difference in the immediate pain relief and long-term e efficacy, between the two groups (P>0.05). Complication rate in the PBC-group was significantly lower than that in the MVD-group (3.77% vs 17.78%, P<0.05). Medical records within 14 days after the operation showed that the incidence of facial numbness and masticatory muscle weakness in the PBC-group were 37.74% and 28.30% respectively, significantly higher than those in MVD-group (4.44% and 2.22%) (P<0.05). These symptoms gradually improved three months after the surgery, and were almost completely resolved after six months. Conclusions: Compared with MVD, PBC has the same effect in the treatment of TN. PBC is a minimally invasive, safe, and effective method with a low complication rate. Although masticatory muscle strength is slightly impacted by PBC, it gradually recovers within six months after the operation.

A Study on the Efficacy of Three-Dimensional CT Bronchial Angiography in Thoracoscopic Precision Resection of Lung Segments.

Objective: This study aimed to evaluate the effectiveness of three-dimensional CT bronchial angiography (3D-CTBA) in facilitating precise lung segmental resection. Methods: A total of 80 patients with peripheral lung nodules undergoing anatomical lung segmentectomy were randomly divided into two groups: a control group (n = 40) and a study group (n = 40). The control group received surgical treatment based on chest CT prompts and traditional lung segmentation, while the study group's chest CT imaging data were reconstructed into 3D images before surgery, followed by lung segmentectomy. Surgical parameters and complication rates were compared between the two groups. Results: The study group exhibited significantly shorter operation time, drainage time, and hospitalization time, as well as reduced intraoperative bleeding, lung tissue resection size, and drainage volume, compared to the control group (P < .05). Hospitalization costs did not differ significantly between the two groups (P > .05). The incidence of lung infection, pulmonary atelectasis, and arrhythmia showed no significant difference between the groups (P > .05). However, the study group demonstrated significantly lower rates of hemoptysis and lung leakage compared to the control group (P < .05). There was no significant difference in the composition of postoperative pathological staging between the two groups (χ2 = 0.721, P > .05). Conclusions: The application of 3D-CTBA technology provides clear visualization of the lung's anatomical structure and contributes to enhanced safety and effectiveness in thoracoscopic lung segmental precision resection.

Preparation of Micron-Sized TS-1 Spherical Membrane Catalysts and Their Performance in the Epoxidation of Chloropropene.

Titanium silica (TS-1) membrane catalysts grown on the surfaces of spherical substrates can both exploit the high catalytic performance and facilitate their separation from products after the reaction. In this work, a simple static crystallization method was used to perform the in situ construction of a TS-1 membrane on the surfaces of micron-sized spherical carriers. The shortcomings of the TS-1 membrane under static crystallization conditions were overcome by in situ dynamic crystallization, and the effect of rotation speed on the formation of the molecular sieve membrane was investigated. The results showed that the molecular sieve membrane was smooth and homogeneous, with a higher synthesis efficiency at a slow rotational speed. The micron TS-1 spherical membrane catalytic chloropropene epoxidation reaction was investigated in a fixed bed, and the conversion of hydrogen peroxide and selectivity of epichlorohydrin reached 99.4 and 96.8%, respectively. After being reused twice, the catalyst still maintained a stable catalytic performance.

Quantum state-resolved molecular dipolar collisions over four decades of energy.

Collisions between cold polar molecules represent a fascinating research frontier but have proven hard to probe experimentally. We report measurements of inelastic cross sections for collisions between nitric oxide (NO) and deuterated ammonia (ND3) molecules at energies between 0.1 and 580 centimeter-1, with full quantum state resolution. At energies below the ~100-centimeter-1 well depth of the interaction potential, we observed backward glories originating from peculiar U-turn trajectories. At energies below 0.2 centimeter-1, we observed a breakdown of the Langevin capture model, which we interpreted in terms of a suppressed mutual polarization during the collision, effectively switching off the molecular dipole moments. Scattering calculations based on an ab initio NO-ND3 potential energy surface revealed the crucial role of near-degenerate rotational levels with opposite parity in low-energy dipolar collisions.

Correlations of Computed Tomography Measurement of Distal Pulmonary Vascular Pruning with Airflow Limitation and Emphysema in COPD Patients.

Background: Pulmonary vascular alteration is an important feature of chronic obstructive pulmonary disease (COPD), which is characterized by distal pulmonary vascular pruning in angiography. We aimed to further investigate the clinical relevance of pulmonary vasculature in COPD patients using non-contrast computed tomography (CT). Methods: Seventy-one control subjects and 216 COPD patients completed the questionnaires, spirometry, and computed tomography (CT) scans within 1 month and were included in the study. Small pulmonary vessels represented by percentage of cross-sectional area of pulmonary vessels smaller than 5 mm2 or 5-10 mm2 to the total lung fields (%CSA<5 or %CSA5-10, respectively) were measured using ImageJ software. Spearman correlation was used to investigate the relationship between %CSA<5 and airflow limitation. A receiver operating characteristic (ROC) curve was built to evaluate the value of %CSA<5 in discriminating COPD patients from healthy control subjects. Segmented regression was used to analyze the relationship between %CSA<5 and %LAA-950 (percentage of low-attenuation areas less than -950 HU). Results: We found a significant correlation between %CSA<5 and forced expiratory volume in one second (FEV1) percentage of predicted value (%pred) (r = 0.564, P < 0.001). The area under the ROC curve for the value of %CSA<5 in distinguishing COPD was 0.816, with a cut-off value of 0.537 (Youden index J, 0.501; sensitivity, 78.24%; specificity, 71.83%). Since the relationship between %CSA<5 and %LAA-950 was not constant, performance of segmented regression was better than ordinary linear regression (adjusted R2, 0.474 vs 0.332, P < 0.001 and P < 0.001, respectively). As %CSA<5 decreased, %LAA-950 slightly increased until an inflection point (%CSA<5 = 0.524) was reached, after which the %LAA-950 increased apparently with a decrease in %CSA<5. Conclusion: %CSA<5 was significantly correlated with both airflow limitation and emphysema, and we identified an inflection point for the relationship between %CSA<5 and %LAA-950.

Facial Flushing Associated with Anxiety and Improved by Venlafaxine: A Case Report.

Facial flushing affects the work and life of patients. The specific pathogenesis and conditions of facial flushing may be complicated. A 47-year-old perimenopausal woman was presented to the Pain Management with a 4-month history of facial flushing. The patient didn't have any history of special illness or history of allergies. Treatments with methylprednisolone, thalidomide, hydroxychloroquine drugs or sympathetic blockages (stellate ganglion block) were unable to effectively improve the symptoms. We believed that the facial flushing might be associated with the anxiety. After two weeks of venlafaxine medication, the symptoms were 90% relieved. We found that venlafaxine effectively improved flushing that may be related to anxiety.

Correlated rotational excitations in NO-CO inelastic collisions.

We present a joint experimental and theoretical study of rotationally inelastic collisions between NO (X2Π1/2, ν = 0, j = 1/2, f) radicals and CO (X1Σ+, ν = 0, j = 0) molecules at a collision energy of 220 cm-1. State-to-state scattering images for excitation of NO radicals into various final states were measured with high resolution by combining the Stark deceleration and velocity map imaging techniques. The high image resolution afforded the observation of correlated rotational excitations of NO-CO pairs, which revealed a number of striking scattering phenomena. The so-called "parity-pair" transitions in NO are found to have similar differential cross sections, independent of the concurrent excitation of CO, extending this well-known effect for collisions between NO and rare gas atoms into the realm of bimolecular collisions. Forward scattering is found for collisions that induce a large amount of rotational energy transfer (in either NO, CO, or both), which require low impact parameters to induce sufficient energy transfer. This observation is interpreted in terms of the recently discovered hard collision glory scattering mechanism, which predicts the forward bending of initially backward receding trajectories if the energy uptake in the collision is substantial in relation to the collision energy. The experimental results are in good agreement with the predictions from coupled-channels quantum scattering calculations based on an ab initio NO-CO potential energy surface.

Interfacial Engineering of a Phase-Controlled Heterojunction for High-Efficiency HER, OER, and ORR Trifunctional Electrocatalysis.

The development of low-cost and high-performance electrocatalysts for simultaneously boosting the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) is highly crucial but still challenging. Herein, a facile one-step solid-phase polymerization and confined pyrolysis strategy is developed for scalable synthesis of a Fe x P/Fe3C-based (x = 1, 2) heterojunction with controllable iron phosphide crystal phases. By effective heterojunction interface regulation, the strong synergic effect between FeP/Fe3C and N- and P-codoped carbon (NPC) modified the electronic structure, resulting in an excellent electrocatalytic performance for the HER, OER, and ORR synchronously. Typically, the FeP/Fe3C@NPC catalyst exhibits efficient HER activity with a low overpotential of 10 mA cm-2 for the HER (97 mV) and OER (440 mV) and a high half-wave potential of 0.87 V for the ORR, as well as excellent stability in alkaline media. Theoretical calculations demonstrated that Fe3C can promote the activation of water molecules, while FeP is beneficial to the removal of H2 and the FeP/Fe3C heterojunction can facilitate both Volmer and Heyrovsky steps in the HER process simultaneously. Moreover, FeP has a stronger inhibitory effect on OH adsorption, revealing that the FeP/Fe3C heterojunction also shows a better promoting effect for both the OER and ORR, respectively.

Accurate and Efficient SIMS Oxygen Isotope Analysis of Composition-Variable Minerals: Online Matrix Effect Calibration for Dolomite.

High-quality oxygen isotope analysis of composition-variable minerals (e.g., ubiquitous carbonates) using secondary ion mass spectrometry (SIMS) is extremely challenging. The classical off-line procedure, which requires additional electron probe microanalyzer (EPMA) chemical compositions for calibrating instrumental mass fractionation (IMF), is inherently inaccurate and analytically inefficient. In this study, the first accurate and paired SIMS analysis of δ18O and Fe# [molar Fe/(Mg + Fe)] in dolomite is reported. Based on five newly developed dolomite O-isotopic standards with an Fe# range of 0.01-0.35 obtained by SIMS, a novel accurate and rapid online matrix effect calibration method for dolomite O-isotope analysis was developed using concurrent SIMS 18O-16O-56Fe16O-24Mg16O measurements without additional chemical electron probe microanalysis. A logistic equation was proposed as the best-fit curve to represent the δ18O matrix effect based on the 56Fe16O/24Mg16O ratios. For CTD-4 carbonatitic dolomite with variable Fe# but homogeneous oxygen isotopes, the off-line method exhibited highly variable apparent δ18O values in the range of 5.74-10.11‰. The online method yielded a homogeneous δ18O value of 7.94 ± 0.34‰ (2SD, n = 40), which is comparable with that of bulk analysis (7.94 ± 0.20‰; 2SD). Comprehensive analyses validated the online method as the best strategy for performing accurate δ18O analysis of samples with highly heterogeneous compositions. Based on its accuracy, simplicity, and economic feasibility, this method has potential applications in the analysis of composition-complex dolomites, detrital dolomites, and other precious terrestrial and extraterrestrial materials.

Glory scattering in deeply inelastic molecular collisions.

For molecular collisions, the deflection of a molecule's trajectory provides one of the most sensitive probes of the interaction potential and there are general rules of thumb that relate the direction of deflection to precollision conditions. Following intuition, forward scattering results from glancing collisions, whereas near head-on collisions result in back scattering. Here we present the observation of forward scattering in inelastic processes that defies this common wisdom. For deeply inelastic collisions between NO radicals and CO or HD molecules, we observed forward scattering in fully resolved pair-correlated differential cross-sections, despite the low impact parameters that are needed to induce a sufficient energy transfer. We rationalized these findings by extending the textbook model of hard-sphere scattering-taking inelastic energy transfer into account-and attribute the forward scattering to glory-type trajectories caused by attractive forces. This phenomenon, which we refer to as hard-collision glory scattering, is predicted to be ubiquitous. We derive under which conditions hard-collision glory scattering occurs and retrospectively identify such behaviour in previously studied systems.

Deep-Blue Room-Temperature Phosphorescent Carbon Dots/Silica Microparticles from a Single Raw Material.

Blue-emitting room-temperature phosphorescence (RTP) materials have always been one of the major challenges in the field of RTP materials. Deep-blue (430 nm) RTP emitting silica microparticles were prepared via a one-step hydrothermal reaction from a single raw material of 3-aminopropyltriethoxysilane (APTES). APTES provided amino groups and ethyl groups as a nitrogen and carbon source, which was further condensed to be nitrogen-contained carbon dots (CDs). Besides, the siloxane side of APTES was hydrolyzed and formed silica microparticles. The CDs with the potential chromophores (C═O and C-N etc.) were connected to SiO2 via Si-C bonds of APTES. The covalent bonds and the rigid silica network effectively restricted the motions of potential chromophores of the CDs and reduced the energy gap between the singlet state and triplet state, which was favorable to the RTP. It was believed that this work will guide researchers to realize other blue or deep-blue RTP materials.

Two-billion-year-old volcanism on the Moon from Chang'e-5 basalts.

The Moon has a magmatic and thermal history that is distinct from that of the terrestrial planets1. Radioisotope dating of lunar samples suggests that most lunar basaltic magmatism ceased by around 2.9-2.8 billion years ago (Ga)2,3, although younger basalts between 3 Ga and 1 Ga have been suggested by crater-counting chronology, which has large uncertainties owing to the lack of returned samples for calibration4,5. Here we report a precise lead-lead age of 2,030 ± 4 million years ago for basalt clasts returned by the Chang'e-5 mission, and a 238U/204Pb ratio (µ value)6 of about 680 for a source that evolved through two stages of differentiation. This is the youngest crystallization age reported so far for lunar basalts by radiometric dating, extending the duration of lunar volcanism by approximately 800-900 million years. The µ value of the Chang'e-5 basalt mantle source is within the range of low-titanium and high-titanium basalts from Apollo sites (µ value of about 300-1,000), but notably lower than those of potassium, rare-earth elements and phosphorus (KREEP) and high-aluminium basalts7 (µ value of about 2,600-3,700), indicating that the Chang'e-5 basalts were produced by melting of a KREEP-poor source. This age provides a pivotal calibration point for crater-counting chronology in the inner Solar System and provides insight on the volcanic and thermal history of the Moon.

The Efficacy of Adjuvant Corticosteroids in Surgical Management of Chronic Subdural Hematoma: A Systematic Review and Meta-Analysis.

Objective: This systematic review aimed to assess the efficacy of adjuvant corticosteroids in managing patients with chronic subdural hematoma (CSDH) undergoing surgical intervention. Methods: We searched for eligible studies electronically on the databases of PubMed, Embase, and Google Scholar. The last date of the search was 15th Jun 2021. Outcomes were pooled to calculate risk ratios (RR) with 95% confidence intervals (CI). Results: Eleven studies were included. Four of them were randomized controlled trials (RCTs). Six studies reported data on good neurological outcomes but with variable definitions. Combining all studies, we noted no statistically significant difference in good neurological outcome with the use of adjuvant corticosteroids (RR: 0.91 95% CI: 0.74, 1.12 I 2 = 92% p = 0.39). Similar results were obtained on subgroup analysis based on definition and study type. However, the use of adjuvant corticosteroids was associated with a significantly reduced risk of recurrence (RR: 0.51 95% CI: 0.40, 0.64 I 2 = 0% p < 0.0001). The meta-analysis also demonstrated no statistically significant difference in mortality rates with the use of adjuvant corticosteroids (RR: 1.01 95% CI: 0.47, 2.21 I 2 = 76% p = 0.97). The results did not differ between RCTs and non-RCTs. Limited studies reported data on complications, and pooled analysis indicated no significant increase in infectious, gastrointestinal, and neurological complications with the use of adjuvant corticosteroids. Conclusion: The use of corticosteroids with surgery for CSDH might be associated with a reduction in recurrence rate. However, corticosteroids do not improve functional outcomes or mortality rates. Future studies should assess the impact of different corticosteroid regimens on patient outcomes, and should use standardized reporting of neurological outcomes with uniform follow-up duration.

Impact and Correction of Analytical Positioning on Accuracy of Zircon U-Pb Dating by SIMS.

Secondary ion mass spectrometry (SIMS) is one of the most important analytical tools for geochronology, especially for zircon U-Pb dating. Due to its advantages in spatial resolution and analytical precision, SIMS is the preferred option for multi-spot analyses on single zircon grain with complex structures. However, whether or how much the relative positions of multiple analytical spots on one zircon grain affect the U-Pb age accuracy is an important issue that has been neglected by most researchers. In this study, we carried out a series of investigation on the influence of relative analytical position during zircon U-Pb age analyses, using Cameca IMS 1280-HR instrument. The results demonstrated a significant influence on the second spot, with apparent U-Pb age deviation as high as around 10% especially on the left and right side with overlap in the raster area. Nevertheless, a linear correlation between a secondary ion centering parameter (DTCA-X) and age deviation in percentage terms was found, and a calibration method was established to correct this position effect. Four zircon standards (91500, M257, TEMORA-2, and Plesovice) were measured to prove the reliability of the established procedure. The original U-Pb apparent data show inconsistent deviation on four directions relative to the datum, while the final U-Pb age results is calibrated to be consistent with their recommended values, within uncertainties of ~1%. This work calls for re-examination for the previous SIMS U-Pb dating results on core-rim dating strategy, and provides a calibration protocol to correct the relative position effect.

Blockade of adenosine A1 receptor in nucleus tractus solitarius attenuates baroreflex sensitivity response to dexmedetomidine in rats.

The α2-adrenergic receptor (α2-AR) agonist dexmedetomidine increases baroreflex sensitivity (BRS). In the current study, we examined the potential role of adenosine A1 receptor (A1R) within the nucleus tractus solitaries (NTS) in such a response. Briefly, adult male Sprague-Dawley rats were anesthetized and randomly received microinjection of selective A1R antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 0.1 pmol/1 µl) or saline vehicle into the right NTS. Ten min after the microinjection, dexmedetomidine infusion started at a rate of 30 µg/kg over 15 min followed by infusion at 15 µg·kg-1·h-1 for 105 min, or 100 µg/kg over 15 min followed by infusion at 50 µg·kg-1·h-1 for 105 min. BRS was examined using a standard phenylephrine method prior to infusion (T0), 60 min (T1) and 120 min (T2) after dexmedetomidine infusion started. Adenosine concentration in plasma and brainstem was measured with high-performance liquid chromatography with vs. without α2-AR antagonist atipamezole pretreatment (0.5 mg/kg, i.p.). Dexmedetomidine increased BRS at both 30 (T0: 0.55 ± 0.25 vs. T1: 2.45 ± 0.37, T2: 2.26 ± 0.56 ms/mmHg, P < 0.05) and 100 µg/kg (T0: 0.63 ± 0.24 vs. T1: 6.21 ± 1.87, T2: 6.30 ± 2.12 ms/mmHg, P < 0.05). DPCPX pretreatment obliterated BRS response to 100-µg/kg dexmedetomidine. At 100 µg/kg, dexmedetomidine increased adenosine concentration in plasma (0.23 ± 0.11 to 0.45 ± 0.07 µg/ml, P < 0.05) and brainstem (1.46 ± 0.30 to 2.52 ± 0.22 µg/ml, P < 0.05); such effect was blocked by atipamezole pretreatment. Western blot analysis showed α2-AR up-regulation by 100-µg/kg dexmedetomidine, which can be prevented by DPCPX. Double-labeling with glial fibrillary acidic protein showed α2-AR up-regulation in astrocytes in the NTS. These results suggest that dexmedetomidine enhances baroreflex sensitivity, possibly by increasing adenosine in NTS and α2-AR expression in astrocytes.