Experimental Physiology最新文献

{"title":"Chronic sustained hypoxia alters the pattern of diaphragm electrical activity in anaesthetized rats.","authors":"Jamal Khalilpour, Mohammad Reza Alipour, Parviz Shahabi","doi":"10.1113/EP092211","DOIUrl":"https://doi.org/10.1113/EP092211","url":null,"abstract":"<p><p>Chronic sustained hypoxia (CSH) is known to induce functional and structural changes in the respiratory system. The diaphragm, as the main inspiratory muscle of mammals, is particularly important in the neuromotor regulation of respiration. Diaphragm electromyography (dEMG) records the sum of motor unit action potentials (MUAP) and provides information regarding motor unit recruitment and frequency coding during muscle contraction. We aimed to assess changes in dEMG activity following CSH. Herein, eight male Wistar rats (2-3 months) were subjected to CSH (10 ± 0.5% O₂) for 10 successive days. In vivo dEMG recording was employed to assess changes in the diaphragm electrical activity. Filtered and rectified dEMGs were used for further analyses. Findings showed that CSH for 10 consecutive days significantly changed the pattern of dEMG signals. The slope of the rising phase of RMS-enveloped dEMG bursts was much steeper in CSH rats compared to normoxic control rats (rise time: 373 vs. 286 ms; P = 0.005). Burst frequency significantly decreased following CSH (59 vs. 42 bursts/min; P = 0.0001), which was associated with a significant increase in burst amplitude (P = 0.039) and inter-burst duration (0.65 vs. 0.88 s; P = 0.041). Power spectral density analyses showed that the mean frequency (293 vs. 266 Hz; P = 0.033) and high-frequency to low-frequency power ratio (P = 0.009) of dEMG signals significantly declined in CSH rats. Notably, the regularity of frequency and amplitude of dEMG signals did not change significantly following CSH.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143482554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-tone suppression between the ultrasounds above and within the hearing range in mice.","authors":"Noriko Nagase, Hirokazu Kousaki, Bakushi Ogawa, Kazuhiro Horii, Iori Niitsu Morimoto, Chikara Abe, Takenori Ogawa, Fumiaki Nin","doi":"10.1113/EP092317","DOIUrl":"https://doi.org/10.1113/EP092317","url":null,"abstract":"<p><p>Hearing range differs among various species. Ultrasound, which is audible to microbats and dolphins, is inaudible to humans through air conduction. However, it can create an auditory sensation when the stimulation is transmitted through the temporal bone. This phenomenon is known as ultrasonic hearing - sounds at frequencies exceeding the normal hearing range participate in audition. Mice are among the animals that possess one of the highest upper limits of the hearing range. Although ultrasonic hearing has been experimentally demonstrated in humans and guinea pigs, its existence in mice and interaction with ultrasound within the hearing range remain unknown. In this study, we found that ultrasound above the hearing range delivered through the temporal bone evokes the cochlear microphonic potential (CM) in mice. The CM synchronized with the applied single-tone ultrasound, and was actively amplified. Furthermore, the amplitudes of the CM were suppressed by sound with subharmonic frequencies of the applied frequencies. The results indicate that hair cells in mice can detect ultrasound stimuli with frequencies over 120 kHz and ultrasounds within and above the hearing range evoked hair cell currents at the close position along the cochlea.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143482556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Repetition-dependent acutecardiopulmonary responses during intensity-matched squats in males.","authors":"Johannes Lässing, Sonja Hummelmann, Maxi Kramer, Ulrich Laufs, Sven Fikenzer, Roberto Falz","doi":"10.1113/EP092363","DOIUrl":"https://doi.org/10.1113/EP092363","url":null,"abstract":"<p><p>The 'strength-endurance continuum' is a key concept in strength training (ST). Although cardiopulmonary responses have seldom been reported in conjunction with ST, this repeated-measurement study examined acute blood pressure and haemodynamic responses continuously depending on the number of repetitions but without changing the intensity. Fifteen healthy male participants (21.6 (2.0) years; mean (SD)) performed an incremental exercise test and a 3-repetition maximum test (3-RM) on a Smith machine. They were then randomly assigned to three ST sessions involving 10, 20 and 30 repetitions at 50% of their 3-RM. Blood pressure (vascular unloading technique) and cardiopulmonary responses (spirometry and impedance cardiography) were continuously monitored. Heart rate (121 (10) vs. 139 (22) vs. 153 (13) bpm, P = 0.001, respectively), cardiac output (10.4 (1.9) vs. 13.6 (3.8) vs. 14.6 (3.1) L/min, P = 0.001, respectively) and diastolic blood pressure (113 (8) vs. 116 (21) vs. 135 (22) mmHg, P = 0.001, respectively) increased in the training sessions with higher repetitions. Stroke volume, systolic blood pressure and end-diastolic volume indicated no change in peak values between training sessions. Total peripheral resistance (13.6 (2.8) vs. 11.3 (3.6) vs. 11.2 (3.1) mmHg min/L, P = 0.002, respectively) was significantly lower with 20 and 30 repetitions, while oxygen uptake ( <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <msub><mi>O</mi> <mn>2</mn></msub> </msub> <annotation>${dot V_{{{mathrm{O}}_{mathrm{2}}}}}$</annotation></semantics> </math> : 15.5 (1.9) vs. 20.5 (4.1) vs. 20.6 (4.4) mL/min/kg, P = 0.001, respectively) was significantly higher. ST of moderate intensity with an exhausting number (>20) of repetitions induces strong haemodynamic responses, especially high cardiac afterload and a compensatory heart rate acceleration, which may also create a strong stimulus for cardiopulmonary adaptation.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143476455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decoding the space integrome: Personalized countermeasures for a mission to Mars.","authors":"Damian M Bailey","doi":"10.1113/EP092629","DOIUrl":"https://doi.org/10.1113/EP092629","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143466610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intact microdissection of stellate ganglia in a Parkinson's disease model reveals aggregation of mutant human α-synuclein in their cell bodies.","authors":"Bonn Lee, Shiraz Ahmad, Charlotte E Edling, Fiona E N LeBeau, Kamalan Jeevaratnam","doi":"10.1113/EP092261","DOIUrl":"https://doi.org/10.1113/EP092261","url":null,"abstract":"<p><p>Cardiac dysautonomia plays an important role in understanding Parkinson's disease (PD), with recent studies highlighting the presence of α-synuclein in cardiac tissue. We hypothesise that sympathetic dysregulation observed in PD may involve pathological changes caused by α-synuclein in stellate ganglia (SG). This study aimed to investigate α-synucleinopathy in SG of the genetic PD murine animal model. Mice overexpressing Ala30Pro (A30P) mutant α-synuclein were used. We here demonstrate a technique for meticulously dissecting SG. The collected SG from the transgenic mice were immunolabelled with neuronal markers, A30P human mutant α-synuclein and anti-α-synuclein aggregates. A30P mutant α-synuclein protein was expressed in the sympathetic neuronal (tyrosine hydroxylase (TH)-positive) cell bodies. Approximately 27% of the TH-positive cell bodies expressed the A30P mutant α-synuclein protein. The mutant protein was densely localised at the cardiopulmonary pole of the SG. Additionally, we observed that the A30P mutant protein formed fibril aggregation in the SG. Our findings suggest that α-synucleinopathy in the PD animal model can affect the sympathetic autonomic nervous system, providing insight for further research into targeting α-synuclein pathology in the SG as a potential link between cardiac dysautonomia and PD.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143476388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The state of mechanistic research in the evidence-based medicine era: A sandwalk between triangulation and hierarchies.","authors":"Ronan M G Berg, Cody G Durrer, Jan Kyrre Berg Olsen Friis, Mathias Ried-Larsen","doi":"10.1113/EP092157","DOIUrl":"https://doi.org/10.1113/EP092157","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143467112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of prespecified analysis plans in physiological research: Encouraged or mandatory?","authors":"Robin Christensen, Tobias Haugegaard, Janus C Jakobsen","doi":"10.1113/EP092034","DOIUrl":"https://doi.org/10.1113/EP092034","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143467111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Breath-by-breath measurement of alveolar gas exchange must preserve mass balance and conform to a physiological definition of a breath.","authors":"Michele Girardi, Carlo Capelli, Carrie Ferguson, Susan A Ward, Harry B Rossiter","doi":"10.1113/EP092221","DOIUrl":"https://doi.org/10.1113/EP092221","url":null,"abstract":"<p><p>Tidal breathing in awake humans is variable. This variability causes changes in lung gas stores that affect gas exchange measurements. To overcome this, several algorithms provide solutions for breath-by-breath alveolar gas exchange measurement; however, there is no consensus on a physiologically robust method suitable for widespread application. A recent approach, the 'independent-breath' (IND) algorithm, avoids the complexity of measuring breath-by-breath changes in lung volume by redefining what is meant by a 'breath'. Specifically, it defines a single breathing cycle as the time between equal values of the <math> <semantics><msub><mi>F</mi> <msub><mi>O</mi> <mn>2</mn></msub> </msub> <annotation>${F_{{{mathrm{O}}_2}}}$</annotation></semantics> </math> / <math> <semantics><msub><mi>F</mi> <msub><mi>N</mi> <mn>2</mn></msub> </msub> <annotation>${F_{{{mathrm{N}}_2}}}$</annotation></semantics> </math> (or <math> <semantics><msub><mi>F</mi> <mrow><mi>C</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${F_{{mathrm{C}}{{mathrm{O}}_2}}}$</annotation></semantics> </math> / <math> <semantics><msub><mi>F</mi> <msub><mi>N</mi> <mn>2</mn></msub> </msub> <annotation>${F_{{{mathrm{N}}_2}}}$</annotation></semantics> </math> ) ratio, that is, the ratio of fractional concentrations of lung-expired O₂ (or CO₂) and nitrogen (N₂). These developments imply that the end of one breath is not, by necessity, aligned with the start of the next. Here we demonstrate how the use of the IND algorithm fails to conserve breath-by-breath mass balance of O₂ and CO₂ exchanged between the atmosphere and tissues (and vice versa). We propose a new term, within the IND algorithm, designed to overcome this limitation. We also present the far-reaching implications of using algorithms based on alternative definitions of the breathing cycle, including challenges in measuring and interpreting the respiratory exchange ratio, pulmonary gas exchange efficiency, dead space fraction of the breath, control of breathing, and a broad spectrum of clinically relevant cardiopulmonary exercise testing variables. Therefore, we do not support the widespread adoption of currently available alternative definitions of the breathing cycle as a legitimate solution for breath-by-breath alveolar gas exchange measurement in research or clinical settings.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143476385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A method for dyadic cardiac rhythmicity analysis: Preliminary evidence on bilateral interactions in fetal-maternal cardiac dynamics.","authors":"Diego Candia-Rivera, Mario Chavez","doi":"10.1113/EP092532","DOIUrl":"https://doi.org/10.1113/EP092532","url":null,"abstract":"<p><p>Cardiac activity responds dynamically to metabolic demands and neural regulation. However, little is known about this process during pregnancy. Reports show occasional fetal-maternal heart rate couplings, but it has remained unclear whether these couplings extend to more complex oscillatory patterns of the heart rhythm. We developed a framework of time-varying measures of heart rate and rhythm, to test the presence of co-varying patterns in concurrent maternal and fetal measures (late pregnancy dataset, n = 10, and labour dataset, n = 12). These measures were derived from first and second-order Poincaré plots, with the aim to describe changes in short- and long-term rhythmicity, but also the dynamic shifts in acceleration and deceleration of heart rate. We found episodes of maternal-fetal co-varying patterns of cardiac rhythm in all the measures explored, in both datasets (at least 90% of the dataset presented a significant maternal-fetal correlation in each measure, with P < 0.001), with dynamic delays suggesting bilateral interactions at different time scales. We also found that these couplings intensify during labour (test between late pregnancy vs. labour datasets, P < 0.0015 in all second-order Poincaré plot-derived measures). While most literature suggests that the fetal heart responds to maternal breathing patterns or contractions, we propose the possibility that the fetal heart may also have a signalling function in the context of co-regulatory mechanisms and maternal inter-organ interactions. Understanding these complex visceral oscillations in utero may enhance the assessment of a healthy fetal development.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143476384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of exercise training on tumour-infiltrating T cells in human prostate cancer: A secondary analysis of a randomized controlled trial (PRO-TEST).","authors":"Simon Nørskov Thomsen, Emil Wriedt, Marianne Gardar Stærk, Sissal Sigmundsdottir Djurhuus, Birgitte Grønkær Toft, Sabrina Wielsøe, Andreas Røder, Thomas Hasselager, Peter Busch Østergren, Henrik Jakobsen, Klaus Brasso, Jesper Frank Christensen, Louise Lang Lehrskov, Casper Simonsen","doi":"10.1113/EP092374","DOIUrl":"https://doi.org/10.1113/EP092374","url":null,"abstract":"<p><p>Exercise training reduces tumour growth by increasing tumour-infiltrating T-cell density in preclinical models. However, it remains unknown whether exercise training can modify intratumoural T cells in humans.The aim of this study was to compare the effects of an exercise training intervention versus control on human prostate intratumoural T-cell density.This study is a secondary analysis of a randomized controlled trial. We randomly allocated men (age > 18 years) with treatment-naive localized prostate cancer scheduled for radical prostatectomy 2:1 to exercise training intervention or control. The exercise intervention consisted of supervised, high-intensity interval bicycling four times per week from the time of randomization until prostatectomy. Intratumoural CD3⁺ and CD8⁺ T-cell densities in diagnostic biopsies and postsurgical prostatectomy specimens were quantified using immunohistochemistry. Between-group differences in changes from baseline to follow-up were estimated using constrained baseline linear mixed-effect models.A total of 30 participants were included (exercise intervention, n = 20; control, n = 10). We found no between-group differences in changes in CD3⁺ T cells [mean difference (95% confidence interval): -17 (-185; 150) cells/mm²] or CD8⁺ T cells [mean difference (95% confidence interval): -16 (-206; 172) cells/mm²]. Additionally, we found no statistically significant correlations between changes in T-cell density and the number of exercise training sessions attended or changes in maximal oxygen consumption.In this secondary analysis of a randomized controlled trial, we found no impact of the exercise regimen on tumour-infiltrating CD3⁺ and CD8⁺ T-cell density in human prostate cancer.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143457358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}