Experimental Physiology最新文献

{"title":"Frequency responses of human magnetophosphene perception thresholds during dark adaptation point to rod modulation.","authors":"Nicolas Bouisset, Andres Carvallo, Sebastien Villard, Ilkka Laakso, Alexandre Legros","doi":"10.1113/EP092852","DOIUrl":"https://doi.org/10.1113/EP092852","url":null,"abstract":"<p><p>Magnetophosphenes are flickering lights perceived when an extremely low frequency magnetic field generates a sufficiently strong electric field in the head. Understanding how phosphenes are produced is crucial, as they form the basis for international safety standards and guidelines for both workers and the general population. However, there is still ongoing debate about whether this phenomenon originates in the retina, the cortex, or involves both. Investigating magnetophosphenes at various frequencies during dark adaptation provides deeper physiological insights into this process. Forty-one participants were exposed to varying levels of magnetic stimulation using a custom global transcranial alternative magnetic stimulation system that provided full-head exposure. Participants were divided into four groups: one light-exposed group and three dark-adapted groups, each assigned a different frequency (20, 50 and 60 Hz). Every 3 min during a 42-min dark adaptation period, participants reported their threshold for magnetophosphene perception. Flux density thresholds were then compared across groups using repeated measures ANOVAs. The data acquired showed a significant (F(15, 270) = 3.637, P < 0.001) increase in the magnetophosphene threshold throughout the 42-min darkness adaptation period. An inversed exponential decay regression was used to model the time course of the magnetophosphene threshold for each frequency. The rising magnetophosphene threshold during dark adaptation is likely linked to retinal phototransduction mechanisms, suggesting that magnetophosphene perception originates from rod cells in the retina. In addition to their significance for establishing new international guidelines and safety standards for workers and the public, our findings could also pave the way for new research into non-invasive assessments of retinal dysfunction.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091680","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":"Atrial fibrillation, sinoatrial and atrioventricular node dysfunction in a mouse model of heart failure with preserved ejection fraction.","authors":"Bernadin Ndongson-Dongmo, Reinhard Bauer, Finn Olav Levy","doi":"10.1113/EP092628","DOIUrl":"https://doi.org/10.1113/EP092628","url":null,"abstract":"<p><p>Millions of people are affected by atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF), two disorders frequently found simultaneously. However, the interrelationship between these intertwined disorders is poorly understood, partly owing to the lack of preclinical models. We aimed to evaluate whether a recently developed mouse model of HFpEF could also be used as a model of AF and, potentially, to study the co-occurrence and interrelationship between the two conditions. Mice were fed a dietary regimen of high-fat diet and N^ω-nitro-l-arginine methyl ester in the drinking water to induce HFpEF. Twenty-four-hour ECG recordings acquired by telemetry were analysed for autonomic imbalance. After 24 h ECG recording, mice received isoprenaline, and a further 1 h of recording was assessed for chronotropic incompetence, susceptibility to atrial arrhythmia and conduction impairment. Evaluation of diastolic function was achieved by transcarotid catheterization and histological analysis performed on the hearts. Resting heart rate was significantly increased after 3 weeks of the dietary regimen, with a trend observed as early as 1 week. Premature atrial contractions, sinus pauses and atrioventricular blocks occurred significantly after 3 weeks of the dietary regimen. Significant diastolic dysfunction, chronotropic incompetence and higher occurrence of AF after isoprenaline stimulation were observed in the HFpEF group at 6 weeks of the dietary regimen. Our study revealed that sinoatrial node and atrial dysfunction precede the simultaneous occurrence of AF, diastolic dysfunction and chronotropic incompetence. This mouse HFpEF model might be helpful for studying the interdependence between AF and HFpEF.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145079989","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":"NEX4EX - A novel exercise device enabling resistive, plyometric and sensorimotor training during deep-space missions: A case report.","authors":"Jonas Böcker, Jochen Zange, Markus Gruber, Guillaume Fau, Rainer Rawer, Sören Törholm, Arnaud Runge, Jörn Rittweger","doi":"10.1113/EP092721","DOIUrl":"https://doi.org/10.1113/EP092721","url":null,"abstract":"<p><p>During weightlessness, the human neuro-muscular-skeletal system undergoes maladaptation to the microgravity environment. The European Space Agency (ESA) project NEX4EX, 'Novel Exercise Hardware for Exploration', developed an advanced multipurpose exerciser offering resistive (RES), plyometric (PLYO) and sensorimotor (SENSO) exercises. It is the aim of this case report to assess the functionality of the device. NEX4EX offers RES in terms of squats and heel raises, and PYLO in terms of countermovement jumps and hops. RES and PLYO were compared with standard exercises on ground as reference. SENSO were generated by creating disturbances of the body posture by means of random, rapid pulling on a shoulder harness in four directions and by an oscillating platform. For SENSO, the results showed clear postural reflexes in trunk and leg muscles to stabilise upright posture after perturbation stimuli at the shoulders. RES and PLYO were carried out accurately on NEX4EX by the participants, but with reduced loads compared to reference (up to -37% for RES; up to -24% for PLYO). This resulted in reduced muscle activation for RES, whereas the muscle activation stayed comparable for PLYO. A reduced maximum take-off velocity during PLYO (up to -66%) was shown leading to a reduced jump height (up to -72%). Although some exercises could not be performed with the same intensity with NEX4EX, in general it enabled all intended exercises. The basic functionality of the device was shown, and thus the device showed its potential as an integrative countermeasure device for upcoming deep-space missions.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145069226","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":"Systolic-dominant coronary flow in rats and mice: Challenging the diastolic paradigm across conscious and anaesthetized states.","authors":"Heidi L Lujan, Theodore W Kurtz, Stephen E DiCarlo","doi":"10.1113/EP092514","DOIUrl":"https://doi.org/10.1113/EP092514","url":null,"abstract":"<p><p>Extensive research in humans, dogs, rabbits, rats, mice and other mammals has consistently demonstrated that coronary blood flow (CBF) peaks during ventricular diastole. For example, studies using transthoracic Doppler echocardiography in anaesthetized rats and mice, isolated blood-perfused rat hearts and Doppler probes sutured to the myocardial surface have reported diastolic-dominant CBF. In contrast, while evaluating the effects of dietary salt on coronary vascular resistance in rats, we unexpectedly observed that left CBF peaked during ventricular systole. This observation prompted two follow-up protocols to test the hypothesis that left coronary flow in rats and mice peaks during systole. In Protocol 1, chronically instrumented conscious male Sprague-Dawley rats were implanted with telemetry pressure sensors and pulsed Doppler flow probes around the ascending aorta and left main coronary artery. Coronary and aortic flow waveforms exhibited nearly identical timing, indicating that CBF peaked during systole. In Protocol 2, anaesthetized, open-chest, mechanically ventilated rats and mice (both sexes) were studied. Doppler probes and ECG electrodes were used to compare the time from the R wave to the peak of both aortic and coronary flow. Student's paired t-test showed no significant difference between the two, confirming that coronary and aortic flow occur synchronously during systole. These findings demonstrate that, in rats and mice, left coronary blood flow peaks during ventricular systole - not diastole - challenging the widely accepted paradigm. This may reflect structural and haemodynamic features unique to small mammals, such as low ventricular wall tension and high heart rates.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145063803","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":"Surviving stabbing: The physiology of knife crime.","authors":"Hugh Montgomery, Mike Tipton","doi":"10.1113/EP093241","DOIUrl":"https://doi.org/10.1113/EP093241","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145063827","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":"Continuous carbon dioxide monitoring in the exhaled breath of mechanically ventilated rats.","authors":"Christin Wenzel, Silke Borgmann, Bernd Flamm, Lea Kuhn, Stefan Schumann, Johannes Schmidt, Johannes Spaeth, Sashko Spassov","doi":"10.1113/EP093058","DOIUrl":"https://doi.org/10.1113/EP093058","url":null,"abstract":"<p><p>In small animals, carbon dioxide monitoring is either limited by the need to take blood samples for gas analysis, or it interferes with respiratory efficiency and lung mechanics analysis. We introduced a novel approach for continuous monitoring of CO₂ in the expiratory limb of the breathing circuit. The relevance of the method is assessed by CO₂ measurements at different respiratory settings. Rats were ventilated with a tidal volume (V_T) of 8 mL kg^-1. Respiratory rates were adjusted to achieve arterial CO₂ partial pressure ( <math> <semantics><msub><mi>P</mi> <mrow><mi>aC</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${P_{{mathrm{aC}}{{mathrm{O}}_2}}}$</annotation></semantics> </math> ) between 35 and 45 mmHg. We measured partial pressure of CO₂ in the expiratory limb of the breathing circuit (exCO₂). exCO₂ values were compared to <math> <semantics><msub><mi>P</mi> <mrow><mi>aC</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${P_{{mathrm{aC}}{{mathrm{O}}_2}}}$</annotation></semantics> </math> from blood gas analysis. The agreement between the two measurements was assessed by correlation and Bland-Altman analysis. The validity of the novel approach was established through additional experimental runs with V_T of 7 or 6 mL kg^-1, where the respiratory rate was set in accordance to exCO₂. Measurements of exCO₂ reflected <math> <semantics><msub><mi>P</mi> <mrow><mi>aC</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${P_{{mathrm{aC}}{{mathrm{O}}_2}}}$</annotation></semantics> </math> with high correlation (R²= 0.8658). Bland-Altman analysis showed high agreement between the two measurements. Respiratory rate setting guided by exCO₂ (39 ± 2 or 40 ± 2 mmHg during ventilation with V_T of 7 or 6 mL kg^-1, respectively) was appropriate to maintain <math> <semantics><msub><mi>P</mi> <mrow><mi>aC</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${P_{{mathrm{aC}}{{mathrm{O}}_2}}}$</annotation></semantics> </math> (41 ± 2 mmHg for both V_T). Measurement of exCO₂ provides a robust estimate of <math> <semantics><msub><mi>P</mi> <mrow><mi>aC</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${P_{{mathrm{aC}}{{mathrm{O}}_2}}}$</annotation></semantics> </math> in anaesthetized small animals during mechanical ventilation. Continuous monitoring of CO₂ in the exhaled breath could be used to guide mechanical ventilation settings.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145063853","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 effects of e-cigarette use on asthma severity in adult BALB/c mice.","authors":"Jenield J D'abreo, Emily K Chivers, Peter B Noble, Luke J Berry, Rachel R Huxley, Arthur Bill W Musk, Peter J Franklin, Benjamin J Mullins, Katherine R Landwehr, Alexander N Larcombe","doi":"10.1113/EP092959","DOIUrl":"https://doi.org/10.1113/EP092959","url":null,"abstract":"<p><p>Electronic cigarettes (e-cigarettes) are often perceived to be a less harmful alternative to tobacco cigarettes. Potentially due to this perception, they are used by people with pre-existing respiratory conditions, such as asthma, who otherwise would not smoke. Despite this, there are few studies exploring the health effects of e-cigarette use on pre-existing asthma. In this study, a house dust mite-induced allergic-airways disease phenotype was generated in adult BALB/c mice over 7 weeks. For the last 2 weeks of this period, mice were also exposed to either medical air, or tobacco smoke or e-cigarette aerosol (with or without nicotine) for 2 h/day. Twenty-four hours later, respiratory parameters including lung volume/function and responsiveness to methacholine were assessed. Biological samples were taken for analysis of pulmonary cellular inflammation and mediator levels, serum IgE and lung/airway structure. There were complex effects of exposure on respiratory outcomes. For example, tobacco smoke-exposed mice of both sexes were the most responsive to methacholine but had suppressed total cellular and eosinophilic inflammation. Female e-cigarette aerosol-exposed mice had impaired parenchymal mechanics at functional residual capacity compared with tobacco smoke-exposed mice, irrespective of nicotine. Interferon γ levels were suppressed in both e-cigarette-exposed groups. There was no effect of any exposure on IgE or lung structural parameters. E-cigarette aerosol exposure exacerbated aspects of an allergic airways disease phenotype in mice. This suggests that asthmatics should exercise increased caution if thinking of using e-cigarettes.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145063790","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":"Why is the muscle spindle so complicated?","authors":"Vaughan G. Macefield","doi":"10.1113/EP093012","DOIUrl":"10.1113/EP093012","url":null,"abstract":"&lt;p&gt;The muscle spindle, one of my favourite sensory organs (along with the Ruffini ending, a much simpler receptor), is an encapsulated stretch receptor embedded within skeletal muscles. It is a complex structure that contains two types of mechanosensitive endings the primary (group Ia) and secondary (group II), and has been the subject of detailed physiological investigation for 100 years (since the first recordings from single afferents of muscle spindle primary endings by Adrian and Zotterman was published in &lt;span&gt;1926&lt;/span&gt;), yet its operation continues to yield surprises. As the only mechanoreceptor in the somatosensory nervous system with its own motor supply [the fusimotor (gamma) motoneurones, which regulate the sensitivity of the primary and secondary endings to stretch], it truly is a wonderful beast. But do we really know how it transduces stretch? Bob Banks and Guy Bewick have been erstwhile explorers hunting this beast and trying to uncover its secrets for several decades, and we now know much about the underlying physiology of the muscle spindle (Bewick &amp; Banks, &lt;span&gt;2015&lt;/span&gt;), but the journey is far from over. Indeed, the muscle spindle is a gift that keeps on giving. Although it is known that PIEZO2 is required for the spindle ending to generate spontaneous activity and to respond to changes in muscle length (Woo et al., &lt;span&gt;2015&lt;/span&gt;), other factors are certainly at play.&lt;/p&gt;&lt;p&gt;For instance, did you know that synaptic-like vesicles in the receptor ending release glutamate (the main excitatory neurotransmitter within the CNS) when stretch is applied and that this influences the sensitivity of the ending; moreover, did you also know that exogenously applied glutamate increases the firing of the afferents (Banks et al., &lt;span&gt;2002&lt;/span&gt;; Bewick et al., &lt;span&gt;2005&lt;/span&gt;)? Like many physiological processes, this autogenic facilitation by glutamate and the recycling of synaptic-like vesicles depends on calcium, which is also essential for initiating the receptor potential. And now, perhaps, we know how. In this special issue, Simon et al. (&lt;span&gt;2025&lt;/span&gt;) interrogate the different types of voltage-gated calcium channels: in neurones, N and P/Q channels are expressed presynaptically and postsynaptically and subserve key roles in synaptic transmission, whereas the L-type channels are found only on the cell bodies and proximal dendrites of neurones, postsynaptically. Using selective calcium channel toxins and pharmacological agents, the authors conclude that the N and P/Q channels are involved in regulating the stretch sensitivity of the spindle ending, whereas only the L-type channel contributes to synaptic-like vesicle recycling.&lt;/p&gt;&lt;p&gt;However, the story gets even more complicated. Not to be outdone, it now turns out that transient receptor potential vanilloid 4 (TRPV4), a non-selective cation channel that features in diverse physiological processes and has been implicated in several neurological disease states (Zhang ","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":"110 10","pages":"1389-1390"},"PeriodicalIF":2.8,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://physoc.onlinelibrary.wiley.com/doi/epdf/10.1113/EP093012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145039489","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":"<ArticleTitle xmlns:ns0=\"http://www.w3.org/1998/Math/MathML\">Left ventricular morphological and functional predictors of <ns0:math> <ns0:semantics> <ns0:msub><ns0:mover><ns0:mi>V</ns0:mi> <ns0:mo>̇</ns0:mo></ns0:mover> <ns0:mrow><ns0:msub><ns0:mi>O</ns0:mi> <ns0:mn>2</ns0:mn></ns0:msub> <ns0:mi>peak</ns0:mi></ns0:mrow> </ns0:msub> <ns0:annotation>${dot V_{{{mathrm{O}}_2}{mathrm{peak}}}}$</ns0:annotation></ns0:semantics> </ns0:math> : A 3-year observational study.","authors":"Viswanath B Unnithan, Alexander Beaumont, Thomas Rowland, Keith George, Antonio Dello Iacono, Nicholas Sculthorpe, Rachel N Lord, David L Oxborough","doi":"10.1113/EP092871","DOIUrl":"https://doi.org/10.1113/EP092871","url":null,"abstract":"<p><p>The aim of the study was to identify central determinants of <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>peak</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{peak}}}}$</annotation></semantics> </math> using a 3-year longitudinal evaluation of left ventricular (LV) morphological and functional (global, tissue-Doppler and strain) outcome measures obtained at rest and during both submaximal and maximal exercise in a group of highly trained male youth soccer players (SP) and recreationally active male participants (CON). Once a year for 3 years, measurements were obtained in both the SP and CON groups (12.0 ± 0.3 and 11.7 ± 0.2 years of age, respectively, at the onset of the study). Cardiac ultrasound measures were used to identify LV morphological indices at rest and functional parameters during submaximal and maximal exercise. Training status (P < 0.0001) emerged as the only significant independent predictor of <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>peak</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{peak}}}}$</annotation></semantics> </math> , when considering LV morphological variables. At maximal exercise, early diastolic filling (E) was a significant (P = 0.001) predictor of <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>peak</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{peak}}}}$</annotation></semantics> </math> , irrespective of the influence of training status. Training status emerged as the significant predictor of <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>peak</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{peak}}}}$</annotation></semantics> </math> across all models that were developed in this study. Minimal LV structural and functional adaptations at both rest and exercise influence <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>peak</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{peak}}}}$</annotation></semantics> </math> , beyond the impact of training status alone. The broader implication of these findings is that the influence of LV cardiac adaptations on <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>peak</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{peak}}}}$</annotation></semantics> </math> over time is mediated by the stimulus of training; this association occurs independently from the impact of growth and maturation on <math> <semantics> <msub><mover><mi>V</mi> <mo>̇</mo></mover> <mrow><msub><mi>O</mi> <mn>2</mn></msub> <mi>peak</mi></mrow> </msub> <annotation>${dot V_{{{mathrm{O}}_2}{mathrm{peak}}}}$</annotation></semantics> </math> .</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145039368","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":"Cerebral haemodynamic responses to inspiratory muscle work.","authors":"Andrew H Ramsook, Morgan A Hughes, Wyatt W Pruter, Kevin L Webb, Ali Ataie, Chad C Wiggins, Gabrielle A Dillon, Sarah E Baker, Michael J Joyner","doi":"10.1113/EP092840","DOIUrl":"https://doi.org/10.1113/EP092840","url":null,"abstract":"<p><p>Fatiguing inspiratory work has been shown to evoke a sympathetically mediated reflex that has systemic cardiovascular consequences, including increases in heart rate and blood pressure and a decrease in resting limb vascular conductance. Moreover, the response to this reflex appears to be attenuated in females compared with males. It remains to be seen whether this respiratory muscle metaboreflex also exerts an effect on cerebral blood flow. Cerebral blood flow is tightly regulated to maintain homeostasis and critical function. Therefore, it stands to reason that cerebrovascular haemodynamics would not be compromised through this respiratory muscle metaboreflex. We hypothesized that fatiguing inspiratory work would reduce resting limb conductance, but cerebral blood flow would be minimally impaired. Females (34 ± 10 years old, n = 12) and males (31 ± 8 years old, n = 12) performed a 5 min, high-intensity bout of inspiratory pressure threshold loading (IPTL) designed to evoke the respiratory muscle metaboreflex. In response to IPTL, mean arterial pressure increased in both males and females (p < 0.001), and limb vascular conductance decreased to a greater degree in males than in females (p = 0.005). The cerebrovascular conductance index was higher in females (p = 0.007) but not affected by IPTL (p = 0.417). Our findings suggest that cerebral blood flow is spared from the redistribution of blood flow in response to fatiguing inspiratory work and that this protection is true in both males and females.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145039416","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}