bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untargeted Metabolomics Reveal State‐Dependent Neurochemical Changes in Frontal Association (FrA) and Motor Cortex (M1) of C57BL/6J (B6) Mouse
Authors: Bourdon Allen K. , Spano Giovanna , Bellesi Michele , Tononi Giulio , Cirelli Chiara , Serra Pier Andrea , Baghdoyan Helen A. , Lydic Ralph , Cammpagna Shawn R. 
Published: November 2023

Neurochemical monitoring using targeted and untargeted metabolomic approaches can provide unique insights into changes in brain chemistry that occur normally, in response to pathology, and after therapeutic intervention. This study used an established untargeted metabolomics method (Anal. Chem., 82:3212, 2010) to identify known and unknown brain metabolites by means of ultra‐performance liquid chromatography coupled with high‐resolution mass spectrometry (UPLC‐HRMS) on an Exactive Plus Orbitrap Instrument (Thermo Fisher Scientific). To date, analyses have been performed on microdialysis samples (n=408) obtained from FrA and M1 of intact, behaving B6 mice (n=5). Microdialysis samples were collected in conformance with the FASEB Statement of Principles for the use of animals in research during electroencephalographically confirmed intervals of extended wakefulness, recovery sleep, and subsequent extended wakefulness. Partial least squares discriminant analyses showed reliable and statistically significant state‐dependent clustering of metabolites. In addition to identifying approximately 20 known molecules, analyses revealed consistent associations with the first wakefulness period (acetoacetate and lactate), sleep (valine and leucine/isoleucine), and the second wakefulness period (pyruvate and tyrosine). The results also provided a list of unidentified spectral features in FrA (n=33) and M1 (n=43) that are being subjected to additional analyses using the metabolite databases (https://metlin.scripps.edu/index.php and http://www.hmdb.ca). These spectral features may ultimately lead to the discovery of novel molecules not previously known to be associated with states of sleep and wakefulness. By integrating the dynamic sampling tool of microdialysis with the unparalleled capabilities of UPLC‐HRMS, these studies are identifying and quantifying state‐dependent and region‐specific changes in mouse brain metabolome.Support or Funding InformationNIH grants HL65252 (RL and HAB); MH099231 and 1P01NS083514 (CC and GT); and support from the UT Joint Institute for Biological Sciences.
Inflammation Increases the Excitatory Synaptic Transmission in the Nucleus Tractus Solitarius (NTS) of Rats Submitted to Sustained Hypoxia
Authors: Silveira Ludmila Lima , Accorsi‐Mendonca Daniela , Bonagamba Leni GH , Machado Benedito H. 
Published: November 2023

Short‐term sustained hypoxia (SH) is associated with cardiorespiratory changes and inflammatory process in the central nervous system. SH also promotes changes in excitatory synaptic transmission in the NTS. In this study we evaluated the possible role of inflammation triggered by SH on the excitatory synaptic transmission of NTS neurons sending projections to the Ventral Medulla (VM). For this purpose, we used juvenile Wistar rats (90–120g), which were divided into 4 groups: 1) control (FiO2=20.8%) treated with vehicle (saline + distilled water, i.p), 2) control treated with the anti‐inflammatory Minocycline (30mg/kg, i.p), 3) SH (FiO2=10%) treated with vehicle, 4) SH treated with Minocycline. The rats were treated for 3 days and then exposed to SH or normoxia protocol for 24 h. At the end of these protocols, the animals were decapitated and brainstem slices were obtained. Whole cell patch‐clamp technique was used to electrophysiological recordings of NTS neurons sending projections to the VM which were previously identified by retrograde labeling. SH produced no changes in the intrinsic properties of the NTS neurons, but spontaneous excitatory postsynaptic currents (sEPSCs) of NTS neurons from SH animals treated with vehicle presented a higher frequency when compared with the group that was maintained in normoxic conditions [2,4±0,4 (n=7) vs 0,96±0.2Hz (n=13)]. This increase that was not observed in the SH group treated with Minocycline when compared to normoxic group [0,9±0.3Hz (n=6) vs 0,9±0.2Hz (n=7), two‐way ANOVA followed by Bonferroni's post‐test]. The data show that inflammation induces by SH contributes to the increase in excitatory synaptic transmission in the NTS neurons sending projections to VM.Support or Funding InformationFinancial support: CAPES, CNPq, FAPESP.
Brain‐Derived Neurotrophic Factor in Nucleus Tractus Solitarius is increased in Pressure Overload‐Induced Cardiac Hypertrophy via Heart‐to‐Brain Axis
Authors: Takenaka Risa , Ito Koji , Kishi Takuya , Hirooka Yoshitaka 
Published: November 2023

IntroductionCardiac hypertrophy is an independent risk factor for heart failure, and result in baroreflex dysfunction. Baroreflex dysfunction further deteriorates cardiac hypertrophy and, if prolonged, may progress into heart failure with a vicious cycle. However, it remains unclear how cardiac hypertrophy worsens baroreflex via the heart‐to‐brain axis. We focused cardiac afferent nerve as a component of the heart‐to‐brain axis. Nucleus tractus solitarius (NTS) is primary nucleus in central baroreceptor circuit and received cardiac afferent nerve. It is suggested that increased brain‐derived neurotrophic factor (BDNF) in NTS reduces the neuronal activity, which might disrupt baroreflex. The cardiac afferent nerve terminals express a transient receptor potential vanilloid type 1 (TRPV1), and TRPV1 increases in the hypertrophic heart from transgenic mice. We hypothesized that pressure overload‐induced cardiac hypertrophy increases BDNF in NTS via TRPV1 in cardiac afferent nerve.MethodsWe divided wild‐type (WT) and TRPV1 knockout mice (KO) with aortic banding (AB) or sham operation. At 8 weeks after the operation, we evaluated cardiac function by echocardiography and BDNF levels in the NTS by Western blot analysis.ResultEchocardiographic left ventricular hypertrophy and heart weight were significantly greater in WT‐AB than in WT‐sham, and were attenuated in KO‐AB. Western blot analysis revealed a significant increase in BDNF in NTS of WT‐AB compared with WT‐sham (1.26±0.01 vs. 0.90±0.02 units, n=4, P<0.05). However, KO‐AB had significantly lower BDNF in NTS than WT‐AB (1.26±0.01 vs. 1.02±0.02 units, n=4, P<0.05).ConclusionIncreased BDNF in NTS by pressure overload‐induced cardiac hypertrophy was inhibited by knockout of TRPV1. These findings support the novel concept that cardiac hypertrophy disrupts baroreflex via the “heart (TRPV1)‐to‐brain (BDNF in NTS) axis”.Support or Funding InformationThis study was supported by a Grant‐in‐Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan (24390198 to Dr. Hirooka and 25461112 to Dr. Ito).
Select Inhibition of Arcuate NPY/AgRP Neurons Increases Arterial Pressure and Sympathetic Nerve Activity in Mice
Authors: Shi Zhigang , Brooks Virginia L. 
Published: November 2023

Using designer receptors exclusively activated by designer drugs (DREADD) technology, we recently demonstrated that select activation of arcuate nucleus (ArcN) neurons that express Neuropeptide Y (NPY) and agouti‐related protein (AgRP) rapidly and profoundly decreases splanchnic sympathetic nerve activity (SSNA) and mean arterial pressure (MAP) in male mice. The present study tested the hypothesis that ArcN NPY/AgRP neurons tonically suppress SSNA, by determining if inhibition of these neurons increases SSNA. To selectively inhibit ArcN NPY/AgRP neurons, the mutated inhibitory muscarinic receptor (hM4Di) was specifically expressed via bilateral nanoinjection of Cre‐recombinase‐dependent adeno‐associated virus (AAV)‐hM4Di‐mCherry into the ArcN of AgRP‐Ires‐cre mice. After >2 weeks recovery, mice were anesthetized with α‐chloralose and received ip injections of the otherwise inert ligand Clozapine‐N‐oxide (CNO; 0.3 mg/kg; n=4), to activate hM4Di, or saline (n=3). CNO slowly (after ~45 min) increased SSNA from 99±1 to 151±3 % control and increased MAP from 76±7 to 84±7 mmHg (all P<0.01, ANOVA); however, saline had no effects (SSNA: 101±1 to 95±5 % control; MAP: 89±6 to 88±6 mmHg). ArcN NPY/AgRP neurons send major projections to the hypothalamic paraventricular nucleus (PVN) and the dorsal medial hypothalamus (DMH). To begin to identify the sites at which ArcN NPY/AgRP activation (or inhibition) alters SSNA/MAP, we next nanoinjected (30 nL) NPY (3 pmol) or the NPY Y1 receptor antagonist BIBO3304 (0.3 nmol) into the PVN or DMH in anesthetized wild type mice. PVN NPY decreased (n=4; P<0.05) MAP (92±4 to 84±5 mmHg) and SSNA (99±1 to 64±5 % control), whereas PVN BIBO3304 increased (n=3; P<0.05) MAP (82±7 to 95±5 mmHg) and SSNA (95±3 to 137±9 % control). Similarly, DMH NPY decreased (n=3; P<0.05) MAP (99±7 to 79±3 mmHg) and SSNA (100±1 to 71±4 % control), and DMH BIBO3304 increased (n=3; P<0.05) MAP (92±3 to 106±4 mmHg) and SSNA (101±6 to 141±9 % control). In conclusion, ArcN NPY/AgRP neurons tonically suppress SSNA and MAP, possibly in part via NPY projections to the PVN or DMH.Support or Funding InformationAHA 12GRNT11550018 and 15POST23040042
Oxidative Stress Contributes to Microvascular Endothelial Dysfunction in Humans with Major Depressive Disorder
Authors: Greaney Jody L , Santhanam Lakshmi , Saunders Erika F , Alexander Lacy M 
Published: November 2023

Vascular dysfunction is evident in humans with major depressive disorder (MDD); however, the specific molecular mediators remain unclear. In rodent models of depression, oxidative stress‐induced reductions in nitric oxide (NO) bioavailability contribute to impaired endothelium‐dependent vasodilation. We hypothesized that 1) markers of oxidant stress expression and activity would be increased in adults with MDD compared to healthy control (HC) subjects (in vitro), 2) NO‐dependent vasodilation would be attenuated in adults with MDD (in vivo), and 3) acute in vivo scavenging of reactive oxygen species (ROS) would improve endothelial function in MDD. 6 HC (36±9 yrs) and 5 adults with MDD (33±8 yrs) participated; MDD subjects had clinically significant depressive symptoms, classified according to the Center for Epidemiologic Studies Depression Scale (CES‐D score 34±3). NADPH oxidase expression (p47phox subunit; Western blot analysis) and total ROS production (fluorometric assay) were quantified in forearm cutaneous homogenates. Red blood cell flux (laser Doppler flowmetry) was measured during graded intradermal microdialysis infusion of acetylcholine alone (ACh; 10−8‐10−1M) and during co‐infusion with the non‐specific NO synthase inhibitor NG‐nitro‐L‐arginine methyl ester (L‐NAME; 20mM) and the non‐specific antioxidant ascorbate (AA; 20mM). Cutaneous vascular conductance (CVC=flux/mean arterial pressure) was expressed as a percentage of maximum (sodium nitroprusside; local heat to 43°C). NADPH oxidase expression and total ROS production were increased in adults with MDD (P<0.05 for both). ACh‐induced vasodilation was blunted in adults with MDD (96±2 HC v. 72±5 MDD %CVCmax; P<0.05); however, there were no group differences in cutaneous vasodilation during NO synthase inhibition (46±4 HC v. 49±6 MDD %CVCmax; P=0.7). AA infusion improved ACh‐induced vasodilation in MDD (72±5 ACh v. 89±10 AA %CVCmax; P=0.11). These data demonstrate impaired NO‐mediated endothelium‐dependent vasodilation in MDD and further suggest a biochemical mechanism and functional role for oxidant stress in mediating vascular dysfunction in MDD.Support or Funding InformationHL120471‐03 and HL093238‐06
Weight supported quadrupedal treadmill exercise improves insulin sensitivity in a rat model of spinal cord injury and diabetes
Authors: Traughber Terence , Ruiz Emanuel , Estrada Christina , Hinahon Erika , Villanueva Silvia , Deriquito Sara , Yamazaki Katrina , de Leon Ray 
Published: November 2023

Previous studies have shown exercise is a simple and economical therapeutic modality that effectively benefits patients with type 2 diabetes. Spinal cord injured (SCI) individuals have a high risk for developing type 2 diabetes. However, there have been no studies that have examined the effects of treadmill exercise in individuals with SCI and type 2 diabetes. We examined the effects of imposing quadrupedal body weight supported treadmill exercise in a rodent model of SCI and type 2 diabetes. Seventeen rats received a severe spinal cord contusion (T10). One day after the contusion, the rats were placed on a high energy diet (10% fat, 20% sucrose, and 70% rodent chow) and 40 days later, a low dose of streptozotocin (STZ; 30 mg/kg, i.p.) was administered. The rats were assigned to an exercise (n=8) or non‐exercise group (n=9). Exercise consisted of weight supported, quadrupedal treadmill walking (23 cm/s) for 1 hr/day, 5 days/week for 6 weeks. Insulin tolerance tests were performed, hemodynamic measurements were recorded, and heart and hindlimb muscle tissue was harvested after the rats were killed. Based on fasting blood glucose, the high energy diet and STZ treatment was successful in inducing diabetes in the rats (i.e. >140 mg/dL; exercise: 202±50 mg/dL; non‐exercise: 146±29 mg/dL). Fasting blood glucose levels were not significantly different between the groups. However, insulin sensitivity was improved by exercise based on insulin tolerance test. We found significant differences in glucose levels 45 and 60 min after insulin injection indicating a greater insulin sensitivity in the exercised group. Exercise also significantly increased tibialis anterior, gastrocnemius and soleus muscle weights by 7%, 20%, 31% respectively indicating the exercise was effective in activating hindlimb activity in the SCI rats. These findings suggest for the first time that weight supported treadmill exercise can reduce metabolic abnormalities that occur after SCI.Support or Funding InformationNIH grant R15NS082711 to R. de Leon
Aerobic Exercise Improves Nitric Oxide Bioavailability and Endothelium‐Dependent Vasorelaxation in Aortic Rings of Obese Zucker Rats
Authors: Lemaster Kent , DeVallance Evan , Branyan Kayla , Skinner Roy , Brooks Steve , Asano Shinichi , Pitzer Christopher , Olfert Mark , Bryner Randall , Frisbee Jefferson , Chantler Paul 
Published: November 2023

Individuals with metabolic syndrome (MetS) have an increased aortic stiffness which is a strong, independent risk factor for cardiovascular disease. Additionally, MetS is associated with a decreased capacity for endothelium‐dependent, nitric oxide (NO)‐induced vasorelaxation which may contribute to the aortic stiffness and increased afterload on the heart. Obese Zucker rats, a translational rodent model of MetS, develop impaired vascular reactivity in aortic rings concomitant to the onset of MetS pathologies. Therapeutic interventions aimed at improving endothelial functioning are therefore considered important avenues for improving CV outcomes in MetS patients. We hypothesized that a chronic aerobic exercise intervention would improve endothelium‐dependent relaxation to methacholine in isolated aortic rings of obese Zucker rats. A total of 28 lean and obese Zucker rats (LZR and OZR, respectively) underwent 8 weeks of a treadmill exercise protocol beginning at 9 weeks of age. The animals were separated into 4 groups: sedentary LZR (LZR; n=7); sedentary OZR (OZR; n=6); exercise LZR (LZR‐EX; n=7); exercise OZR (OZR‐EX; n=7). Following the intervention, the thoracic aorta was dissected out from each animal and sectioned into rings, some of which were then mounted into an ex vivo wire tension myograph system. The remaining rings were evaluated for NO production in a DAF‐FM diacetate assay. Force transduction was used to measure the changes in aortic tension in response to pharmacological agonists. The aortic rings were mechanically set to 1 gram of tension then pre‐constricted using phenylephrine (1×10−6 μM), followed by a gradual dilation induced by increasing concentrations of methacholine (1×10−9, 1×10−8, 1×10−7, 1×106, 1×10−5 μM, respectively). Sedentary LZR demonstrated greater maximum methacholine‐induced vasorelaxation compared to sedentary OZR (83% vs. 67%) as well as reduced production of NO in the DAF assay. The exercise trained groups experienced significant improvements in maximal relaxation compared to their sedentary counterparts (LZR‐EX 93%; OZR‐EX 81%), as well as increased values of NO production measured in the DAF assay. These results demonstrate that 8 weeks of aerobic exercise enhances endothelial bioavailability and/or production of NO which improves endothelium‐dependent vasorelaxation in the aortas of both LZR and OZR. Exercise training may therefore be an important therapy for promoting greater arterial compliance in individuals with MetS.Support or Funding InformationNIHAHA
Ten Days of Free Wheel Running Alters Cortical Glutamate‐Linked Mitochondrial Respiration in Rat Brain
Authors: George Mitchell A. J. , Brebner Karen , Kane Daniel A. 
Published: November 2023

The mechanisms through which exercise benefits brain function are not completely understood. Appreciation for the role of lactate as a major neuroenergetic fuel, particularly during exercise, has progressed in recent decades; however, the mitochondrial involvement in brain lactate metabolism is not clear. To explore the mechanisms involved, we examined mitochondrial lactate oxidation in brain and skeletal muscle from exercised rats. Respiratory oxygen flux (JO2) was measured in saponin‐permeabilized prefrontal cortex (PFC) and hippocampus (dentate gyrus; DG) samples, as well as red and white gastrocnemius muscle samples from five male Wistar rats (age: approximately 104 days) given access to running wheels. Over ten days of free wheel running, rats attained a maximal daily running distance averaging 2.1 ± 0.5 km. The wheel‐running rats remained relatively weight stable, losing 1.4 ± 3.1 g body mass on average, whereas the five paired control rats gained an average of 39.4 ± 2.8 g over the ten days. On day eleven, high resolution respirometry was performed on exercise and control samples ex vivo. The addition of lactate failed to affect mitochondrial JO2 (ADP + malate) from either brain or muscle in either group. However, JO2 rose significantly following the addition of exogenous NAD+ in each tissue (P < 0.01), implying the lactate dehydrogenase reaction operates outside of the mitochondrial matrix. This interpretation was further supported by inhibition of JO2 following addition of an inhibitor of pyruvate transport, UK‐5099 (P < 0.01). Interestingly, the subsequent addition of glutamate resulted in a disparate increase in mitochondrial JO2 among tissues and treatment. Compared to controls, glutamate‐supported mitochondrial JO2 in wheel runners was significantly greater in PFC (P < 0.05), but not DG. This rise in JO2 likely reflects activation of the malate‐aspartate shuttle through elevated mitochondrial glutamate transport. Paradoxically, wheel runners exhibited lower glutamate‐supported JO2 in red gastrocnemius (P < 0.05). This may be due to the influence of regular exercise on the putative lactate‐malate‐aspartate shuttle. The lactate‐malate‐aspartate shuttle is the interaction between the lactate and malate‐aspartate shuttles to translocate reducing power to the mitochondria. The decline in lactate dehydrogenase activity in skeletal muscle that accompanies aerobic exercise training is expected to negatively influence lactate‐malate‐aspartate shuttling, and may explain our observations in muscle. Collectively, the results of this study suggest that electron shuttling in rat brain following ten days of voluntary exercise is upregulated in PFC. These results also provide further evidence for an indirect mechanism of mitochondrial lactate oxidation in both brain and skeletal muscle.Support or Funding InformationThe Natural Sciences and Engineering Research Council of Canada; The Nova Scotia Health Research Foundation
Associations Between Physical Activity And Lower‐Limb Strength With Bone Parameters In Healthy Young Women: A Pilot Study
Authors: Murai Igor Hisashi , Dantas Wagner Silva , dos Santos Gil Saulo , Teixeira Eurimar Rogerio , Alvarenga Jackeline Couto , Benatti Fabiana , Pereira Rosa Maria Rodrigues , Roschel Hamilton , Gualano Bruno 
Published: November 2023

BackgroundMechanical loading‐induced strain provided from physical activity plays an essential role in promoting bone modeling. Furthermore, muscle contraction is an important factor in maintaining bone mass. Therefore, the study aimed to investigate the relationship between physical activity level and lower‐limb strength with bone mineral density (BMD), bone microarchitecture and body composition in young women.MethodsHealthy young women (age: 29.0±6.2 yrs, BMI: 22.46±2.26 kg/m2, n=14), not engaged in systematic exercise training programs, participated in this cross‐sectional study. Moderate‐to‐vigorous physical activity (MVPA) was assessed by accelerometry (ActiGraph GT3X+) for seven consecutive days. Leg press one repetition maximum (1‐RM) test was conducted in order to evaluate lower‐limb strength. BMD (i.e. assessed in four different skeletal sites, as follows: whole body, total femur, femur neck and lumbar spine) and body composition (i.e. lean mass and bone mineral content [BMC]) were measured by dual‐energy x‐ray absorptiometry. Trabecular bone microarchitecture parameters were measured by high‐resolution peripheral quantitative computed tomography in left tibia.ResultsThere was a positive correlation between MVPA and some skeletal sites, such as: total femur BMD (r=0.62, p=0.041) and femur neck BMD (r=0.63, p=0.038). No significant correlation was observed between MVPA and trabecular bone microarchitecture parameters. MVPA was significant correlated with lean mass (r=0.90, p<0.001) and BMC (r=0.78, p=0.004). Lower‐limb strength was positively correlated with whole body BMD (r=0.66, p=0.009), total femur BMD (r=0.76, p=0.001), femur neck BMD (r=0.69, p=0.006), lumbar spine BMD (r=0.74, p=0.002), as well as tibial trabecular number (Tb.N) (r=0.63, p=0.021), and a negative correlation between tibial trabecular separation (Tb.Sp) (r=−0.55, p=0.050). With regard to body composition, lower‐limb strength was significantly associated with lean mass (r=0.73, p=0.002) and BMC (r=0.83, p<0.001).ConclusionsThese preliminary data show that both lower‐limb strength and physical activity level are positively associated with measurements of BMD in young women, especially in lower‐limb sites. Furthermore, lower‐limb strength, but not physical activity level, is positively associated with tibial trabecular number and negatively associated with tibial trabecular separation.Support or Funding InformationFAPESP (process: 2015/02833‐5)