Experimental Physiology最新文献

{"title":"Against erasure: Restoring Dr Florence Buchanan's missing image in physiology.","authors":"Damian M Bailey","doi":"10.1113/EP093649","DOIUrl":"10.1113/EP093649","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":"2416-2422"},"PeriodicalIF":2.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131103/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147275954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bed rest decreases resting skeletal muscle O₂ uptake and resting energy expenditure in young and elderly subjects.","authors":"Giovanni Baldassarre, Simone Porcelli, Lucrezia Zuccarelli, Lorenza Brocca, Noemi Arboit, Laura Gobbo, Michele Lacerenza, Alessio Marciano, Chiara Motto, Giulia Sanguin, Mladen Gasparini, Boštjan Šimunič, Rado Pišot, Marco Narici, Bruno Grassi","doi":"10.1113/EP092709","DOIUrl":"10.1113/EP092709","url":null,"abstract":"<p><p>A decrease in resting muscle O₂ uptake ( <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>m</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{m}}}}$</annotation></semantics> </math> ) described during bed rest (BR) could determine a decreased whole-body resting energy expenditure (REE), potentially useful during prolonged spaceflights. Two groups of recreationally active men (young [Y], n = 8, age 23 ± 5 years; elderly [E], n = 10, age 69 ± 3 years) underwent a 21-day (Y) or a 10-day (E) horizontal BR without countermeasures. Measurements were performed before and post-BR. Fat-free mass (FFM) was measured by bioimpedance analysis; REE was measured by open-circuit spirometry; resting <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>m</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{m}}}}$</annotation></semantics> </math> was measured by time-domain near-infrared spectroscopy in the vastus medialis during a transient ischaemia; citrate synthase (CS) activity (estimate of mitochondrial volume) was measured on a vastus lateralis muscle biopsy sample. FFM decreased significantly both in Y (-8%, P < 0.001) and in E (-5%, P = 0.009). Both resting <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>m</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{m}}}}$</annotation></semantics> </math> (-45%, -2.1% day^-1 in Y, P = 0.025; -29%, -2.9% day^-1 in E, P = 0.001) and REE (-15%, -0.7% day^-1 in Y, P = 0.012; -12%, -1.2% day^-1 in E, P = 0.012) decreased during BR. CS activity decreased in E (-31%, P = 0.005), whereas the decrease in Y (-12%) did not reach statistical significance (P = 0.38). After resting, <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>m</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{m}}}}$</annotation></semantics> </math> data normalized for CS activity values in post- versus pre-BR were lower in Y (P = 0.021) but not in E (P = 0.99). The decreased resting <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>m</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{m}}}}$</annotation></semantics> </math> and REE may represent a 'recalibration' of ATP supply to a reduced ATP demand, aimed at preventing excessive reactive oxygen species production and muscle atrophy. It would mitigate biological and logistic challenges of prolonged spaceflights, but could negatively impact the health status of the subjects.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":"2599-2612"},"PeriodicalIF":2.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131101/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147591022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The physiology of survival: Heat.","authors":"Josh Foster, Robert D Meade, Tom Matthews","doi":"10.1113/EP093192","DOIUrl":"10.1113/EP093192","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":"2397-2402"},"PeriodicalIF":2.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131073/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145367803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptive mediolateral control during split-belt walking: Energetics of interlimb coordination and enhanced savings following acute intermittent hypoxia.","authors":"Norah M Nyangau, Alysha T Bogard, Aviva K Pollet, Andrew Q Tan","doi":"10.1113/EP093291","DOIUrl":"10.1113/EP093291","url":null,"abstract":"<p><p>Control of frontal plane mechanics requires active integration of sensory feedback to regulate stability in response to gait perturbations, such as split-belt walking (SBW). In comparison to sagittal plane mechanics, mediolateral (ML) kinematic and kinetic adaptations to split-belt perturbations are less extensively reported. Moreover, the associated metabolic cost of ML adaptations and the retention of previously learned adaptations, defined as motor savings, have not been examined concurrently. We investigated bilateral adaptations in step width and peak ML ground reaction forces to an initial SBW and metabolic cost. We also examined the retention of these adaptations during a subsequent SBW (adapt 2). Given evidence that priming the nervous system with acute intermittent hypoxia (AIH) enhances motor adaptation, we compared the magnitude of these adaptations after AIH. Legs on the fast and slow belt increased step width during initial SBW, but the magnitude of width reduced during adapt 2. Distinct kinetic modulation patterns emerged between legs as the initial increase in ML ground reaction forces was attenuated for the slow leg during the braking impulse phase and for the fast leg during the propulsive impulse phase. Metabolic cost reductions were positively associated with adaptations in ML force but not step width. During adapt 2, individuals who received AIH demonstrated greater reductions in step width and ML ground reaction forces during propulsion, suggesting enhanced motor savings. These asymmetrical ML kinetic adaptations contribute to stability and reduced metabolic cost during SBW. These insights might inform the design of training approaches to improve stability in clinical populations.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":"2645-2664"},"PeriodicalIF":2.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131107/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147493397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lipid emulsion modulates myogenic and collagen-related gene expression in skeletal muscle of preterm fetal sheep.","authors":"Xinrui Li, Sarah M Alaniz, Samantha Louey, Jeanene Marie Deavila, Sonnet S Jonker, Min Du","doi":"10.1113/EP093580","DOIUrl":"10.1113/EP093580","url":null,"abstract":"<p><p>Although intravenous lipid emulsions are routinely administered to preterm infants, their specific effects on skeletal muscle development remain unclear. In this study, a soybean oil-based lipid emulsion (Intralipid 20^®) was administered via intravenous infusion to fetal sheep (gestational day 88-90) at a dose rising from 1 g/kg/day (day 0) to 3 g/kg/day (days 2-8). Intralipid infusion did not alter overall fetal body weight, tibialis anterior (TA) muscle mass or serum testosterone levels. Histological analyses revealed no significant differences in muscle fibre diameter or collagen content in TA muscles between groups. However, Intralipid significantly upregulated the expression of key myogenic regulatory genes, including Myog (myogenin) and Myod (myogenic differentiation 1), while downregulating the expression of several genes associated with fibrogenesis: Col1a1 (collagen type I α1 chain), Col3a1 (collagen type III α1 chain), Lh2b (lysyl hydroxylase 2b) and P4ha (prolyl 4-hydroxylase α). In contrast, Intralipid had no significant effect on the expression of genes associated with intramuscular adipogenesis, including Pparg (peroxisome proliferator-activated receptor γ), Pdgfra (platelet-derived growth factor receptor α), Zfp423 (zinc finger protein 423), Slc27a1 (solute carrier family 27 member 1), C/ebpa (CCAAT/enhancer-binding protein α) and Fasn (fatty acid synthase). Similarly, genes related to inflammation, such as Tnfa (tumour necrosis factor α), Il-6 (interleukin 6), Tlr4 (Toll-like receptor 4) and Tlr2 (Toll-like receptor 2), were unaffected. In conclusion, these findings indicate that short-term lipid exposure alters gene expression patterns without measurable structural changes, suggesting that transcriptional responses may precede overt morphological remodelling in fetal skeletal muscle.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":"2627-2636"},"PeriodicalIF":2.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131067/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147644515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Respiratory and non-respiratory airflow characteristics across ingestive and non-ingestive swallowing tasks.","authors":"Elizabeth Cross, Esther Guiu Hernandez, Phoebe Macrae","doi":"10.1113/EP092561","DOIUrl":"10.1113/EP092561","url":null,"abstract":"<p><p>Respiratory-swallowing coordination is critical for safe swallowing. Respiratory phase patterns, indicating the direction of respiration bracketing swallowing, appear minimally altered when oral airflow is measured alongside nasal airflow. Measures from an oronasal facemask also demonstrate broader features of swallowing non-respiratory flow (SNRF) associated with the respiratory-swallowing pause than previously reported. Additionally, nasal and oronasal flow estimates show variability in within-individual respiratory phase patterning. In this study, an oronasal facemask and separate nasal-only mask were used to assess healthy individuals, exploring how instrumentation influences respiratory phase pattern estimates across swallowing tasks. Characteristics of SNRF and variability of respiratory phase patterns were also investigated. Adding oral flow to nasal flow appeared to reduce estimated exhale-swallow-exhale patterning by 13% and increased the estimated frequency of alternative patterns, although this may include some genuine variance between the datasets due to asynchronous data acquisition from each mask. SNRF occurred in 87-97% of swallows, with inward and outward flow occurring at the onset and offset of the respiratory-swallowing pause. Test-retest reliability of respiratory phase patterns within individuals ranged from κ = 0.4 - 0.54, with ≥2 patterns observed across four trials >40% of the time. Findings suggest that adding oral to nasal flow alters estimates of respiratory phase patterns, particularly during ingestive swallowing tasks. SNRF is observed more frequently when measured through a closed system, presenting as inwardly- or outwardly-directed airflow at the beginning or end of the respiratory-swallowing pause. Finally, there appears to be considerable variability in respiratory phase patterning across trials of the same swallowing condition.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":"2696-2712"},"PeriodicalIF":2.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131068/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147472233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sex-based differences in corticospinal excitability and inhibition.","authors":"Alicia M Kells, Alexandra N Pauhl, Anita D Christie","doi":"10.1113/EP093411","DOIUrl":"10.1113/EP093411","url":null,"abstract":"<p><p>The purpose of this study was to perform a novel exploration of sex-based differences in various single- and paired-pulse transcranial magnetic stimulation (TMS)-based measures of corticospinal excitability and inhibition. Thirty participants (15 females) attended one laboratory visit where responses evoked by single- and paired-pulse TMS were recorded using electromyography from the first dorsal interosseous muscle. Excitability was assessed via the motor-evoked potential (MEP) and intracortical facilitation (ICF). Inhibition was assessed via the cortical silent period (CSP), short-interval intracortical inhibition (SICI), and long-interval intracortical inhibition (LICI). Each measure was compared between sexes. Overall, males and females did not significantly differ in excitability (MEP: P = 0.070; ICF: P = 0.194). Males displayed significantly greater inhibition compared to females for the SICI (P = 0.016) and LICI (P = 0.003) measures but not CSP (P = 0.612). These findings suggest that sex may be an important consideration for some (SICI and LICI), but not all TMS-based measures of corticospinal excitability and inhibition.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":"2637-2644"},"PeriodicalIF":2.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131105/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147480349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Moderate maternal nutrient restriction alters type II alveolar epithelial cell density in the non-human primate fetal lung.","authors":"Mitchell C Lock, Hillary F Huber, Cun Li, Sandra Orgeig, Peter W Nathanielsz, Janna L Morrison","doi":"10.1113/EP093319","DOIUrl":"10.1113/EP093319","url":null,"abstract":"<p><p>Restriction of fetal substrate supply has an adverse effect on surfactant maturation in the lung and thus affects the transition from in utero placental oxygenation to pulmonary ventilation ex utero. However, the consequences of reduced fetal substrate supply are dependent on the timing of gestation, severity and duration. We hypothesise that maternal nutrient restriction (MNR) from early pregnancy negatively impacts fetal lung maturation. Female baboons of similar age and weight were randomly assigned to either a control diet (n = 3F, 5M offspring) or MNR (n = 4F, 4M offspring). On a weight-adjusted basis, MNR animals were fed 70% of the feed consumed by controls. Fetal lung tissue was collected at 0.9 gestation (term = 184 days). qRT-PCR and immunohistochemistry were utilised to measure expression of key molecules involved in surfactant maturation, reabsorption of lung liquid, vascularisation and immune cells. MNR decreased type II alveolar epithelial cell density and the mRNA expression of PCYT1A, the gene for choline-phosphate cytidylyltransferase A, the enzyme required for de novo surfactant phospholipid synthesis. However, MNR had no effect on the expression of surfactant proteins in the fetal lung. There was a reduced number of α-smooth muscle actin-stained vessels and presence of CD45⁺ immune cells within the lung of fetuses exposed to MNR. These data indicate that MNR from early pregnancy increases risk of neonatal respiratory complications at birth by impairing the capacity for surfactant maturation, reducing vascularisation within the fetal lung and impairing innate lung immunity.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":"2713-2728"},"PeriodicalIF":2.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131072/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147480304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oxygen diffusion kinetics, buffering capacity and phenotype: A narrative review of oxygen physiology and later phenotype in very preterm infants.","authors":"Chad C Andersen, Danielle N Bailey, Tara M Crawford, Michael J Stark","doi":"10.1113/EP093607","DOIUrl":"10.1113/EP093607","url":null,"abstract":"<p><p>Clinicians often view exposure to supplementary oxygen in preterm infants as a simple reciprocal trade-off between mortality and the risk of vision-threatening retinopathy, but this perspective oversimplifies the underlying physiology. Oxygen moves through a series of spatially distinct compartments without intrinsic regulation, with Fick's law governing the entire process. We suggest that retinopathy of prematurity and cerebral palsy represent opposite ends of a shared continuum of oxygen diffusion injury. Several physiological concepts define this risk matrix. The spatial critical threshold indicates the structural limits of immature microvasculature that impact the diffusion radius. The extinction gradient marks the point at which the capillary-to-cell gradient becomes flat, leading to flux collapse and intracellular hypoxia. Conversely, the hyperoxic injury threshold identifies the point at which intracellular oxygen tension becomes harmful. Lastly, buffering capacity refers to the oxygen bound to haemoglobin in the venous circulation, downstream of metabolism, which is available to buffer temporary mismatches between delivery and consumption. These thresholds explain how hyperoxia and hypoxia can coexist within the same capillary, clarifying distinct clinical phenotypes. Framing oxygen injury this way clarifies contradictions in neonatal trials and offers a physiological model relevant to other diffusion-limited conditions.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":"2485-2493"},"PeriodicalIF":2.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131108/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147632946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Menstrual cycle effects on sex differences in motor control during dynamic balance perturbations.","authors":"Samuli Nevanperä, Ritva S Mikkonen, Simon Walker, Jarmo M Piirainen","doi":"10.1113/EP093608","DOIUrl":"10.1113/EP093608","url":null,"abstract":"<p><p>This study investigated sex differences in neuromuscular responses during dynamic balance perturbations and isometric maximal voluntary contractions (IMVCs) by examining if menstrual cycle (MC) phase and the fluctuations in endogenous hormones influence the observation of sex differences. Twenty-seven young adults (17 males: 28.5 ± 6.4 years; 10 females: 31.2 ± 6.5 years) were measured twice: females were measured at the early-follicular (EF) phase, that is 2-4 days after onset of bleeding, and at the mid-luteal phase (LUT), coinciding with peak levels of progesterone. Males were measured twice with 7-14 days between measurements. During dynamic balance perturbations, H-reflex and V-wave (neural drive) responses were recorded from the posterior perturbations at four latencies (40 ms, 70 ms, 100 ms, and 130 ms) coinciding with short- (SLR), medium- (MLR), and long- (LLR) latency responses and voluntary activation. Further, IMVC and its associated neural drive were assessed. Sex differences in either the H-reflex (P = 0.217) or the V-wave (P = 0.475) were not observed during balance perturbation tasks when females at EF were compared to males. However, when the measurements were conducted at LUT, a significant sex difference was revealed in both H-reflex (P = 0.029) and V-wave (P = 0.049) responses. Similarly, in neural drive during IMVC, no sex differences were observed at EF (P = 0.440), but a significant sex difference at LUT was observed (P = 0.024). Our results suggest that hormonal fluctuation in two distinct MC phases lead to females having lower neural responses during dynamic balance and voluntary force generation tasks at LUT compared to males.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":"2665-2681"},"PeriodicalIF":2.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13131090/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147527967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}