Experimental Physiology最新文献

{"title":"Caffeine in cerebrovascular research: To withdraw or not to withdraw?","authors":"Brooke R Shepley, Kevin J Milne, Anthony Richard Bain","doi":"10.1113/EP092703","DOIUrl":"https://doi.org/10.1113/EP092703","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144224853","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":"Deep-learning models of the ascending proprioceptive pathway are subject to illusions.","authors":"Adriana Perez Rotondo, Merkourios Simos, Florian David, Sebastian Pigeon, Olaf Blanke, Alexander Mathis","doi":"10.1113/EP092313","DOIUrl":"https://doi.org/10.1113/EP092313","url":null,"abstract":"<p><p>Proprioception is essential for perception and action. Like any other sense, proprioception is also subject to illusions. In this study, we model classic proprioceptive illusions in which tendon vibrations lead to biases in estimating the state of the body. We investigate these illusions with task-driven models that have been trained to infer the state of the body from distributed sensory muscle spindle inputs (primary and secondary afferents). Recent work has shown that such models exhibit representations similar to the neural code along the ascending proprioceptive pathway. Importantly, we did not train the models on illusion experiments and simulated muscle-tendon vibrations by considering their effect on primary afferents. Our results demonstrate that task-driven models are indeed susceptible to proprioceptive illusions, with the magnitude of the illusion depending on the vibration frequency. This work illustrates that primary afferents alone are sufficient to account for these classic illusions and provides a foundation for future theory-driven experiments.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215373","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":"Eccentric training at long muscle lengths induces greater corticospinal and spinal reflex plasticity than eccentric training at short muscle lengths.","authors":"Julian Colard, Yohan Betus, Tristan Tallio, Baptiste Bizet, Antoine Nordez, Marc Jubeau, Thomas Cattagni","doi":"10.1113/EP092470","DOIUrl":"https://doi.org/10.1113/EP092470","url":null,"abstract":"<p><p>It is well-established that resistance training generates neural adaptations. These may be greater when exercises mainly include eccentric contractions or when muscles are trained at long length. However, it remains to be clarified whether the length at which muscles are trained influences neural adaptation following eccentric training. We trained 28 healthy young individuals with eccentric exercises for 9 weeks (24 sessions) at either short (n = 13) or long (n = 15) plantar flexor lengths. Participants were assessed once before and once after this training. Estimates of corticospinal excitability and short-interval intracortical inhibition were obtained using transcranial magnetic stimulation and by analysing conditioned or non-conditioned motor evoked potentials. Effectiveness of Ia afferents to discharge α-motoneurons, and post-activation depression induced by primary afferent depolarization were estimated using peripheral tibial nerve stimulation conditioned or not by fibular nerve stimulation, and by analysing Hoffmann reflex amplitude. Maximal plantar flexor torque and voluntary activation were also assessed. The increase in corticospinal excitability and effectiveness of Ia afferents to discharge α-motoneurons were significantly greater after training at long muscle length than at short muscle length (+24.03% and +16.1%, respectively, P < 0.001), without between-group differences in adaptations for short-interval intracortical inhibition, post-activation depression by primary afferent depolarization, maximal torque or voluntary activation level. These results suggest that eccentric training performed at long muscle lengths induces greater adaptations in corticospinal and spinal reflex plasticity. It is crucial to consider muscle length during eccentric training to optimize neuronal plasticity and potentially enhance daily task performances.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144198631","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":"Acute alterations in blood lactate in the setting of transient stress induced myocardial ischaemia.","authors":"Jamie M O'Driscoll, Elliot Smith, Matchel Bibat, Jamie J Edwards, Claire Compton, Konstantina Kipourou, Damian Coleman, Jonathan Wiles, Eliane Cunliffe, Anna Marciniak, Rajan Sharma","doi":"10.1113/EP092429","DOIUrl":"https://doi.org/10.1113/EP092429","url":null,"abstract":"<p><p>An elevation in resting venous blood lactate ([La^-]_b) levels in conditions of myocardial hypoperfusion is associated with adverse prognosis and survival. This investigation aimed to assess changes in venous [La^-]_b levels induced by dobutamine stress in the presence and absence of myocardial ischaemia and adverse outcomes at 1 year. Four hundred and four consecutive patients (mean age 70 ± 10 years, 243 male) reporting chest pain underwent dobutamine stress echocardiography (DSE) and were categorised as ischaemic (IS) or non-ischaemic (NI) responders. Conventional and global longitudinal strain (GLS) echocardiographic measures were recorded at rest. Venous [La^-]_b samples were acquired at rest, peak stress and 1, 3, 5 and 10 min into recovery using a commercially available Lactate Pro 2 device. There were no significant differences in [La^-]_b concentrations between IS (1.75 ± 0.76 mmol L^-1) and NI (1.73 ± 0.60 mmol L^-1) responders at baseline (P = 0.592). However, [La^-]_b concentrations were significantly greater at peak stress (1.83 ± 0.57 vs. 1.68 ± 0.60 mmol L^-1), 1 (1.90 ± 0.56 vs. 1.73 ± 0.71 mmol L^-1), 3 (1.97 ± 0.56 vs. 1.73 ± 0.71 mmol L^-1), 5 (1.98 ± 0.60 vs. 1.74 ± 0.70 mmol L^-1) and 10 min (2.01 ± 0.63 vs. 1.76 ± 0.71 mmol L^-1) into recovery between IS and NI responders (all P < 0.001). GLS was significantly lower in IS compared to NI (-15.5 ± 2.9 vs. -16.2% ± 2.7%, P = 0.02) responders at baseline. In patients who experienced an adverse cardiac event during 1 year of follow-up, GLS (-14.4 ± 2.7 vs. -16.1% ± 2.8%, P < 0.001) and [La^-]_b concentrations were significantly lower at baseline (1.54 ± 0.55 vs. 1.78 ± 0.70 mmol L^-1, P = 0.02), as were [La^-]_b concentrations at 5 (1.68 ± 0.55 vs. 1.88 ± 0.68 mmol L^-1, P = 0.04) and 10 min (1.70 ± 0.56 vs. 1.93 ± 0.71 mmol L^-1, P = 0.02) into recovery compared to patients who did not experience an adverse event. GLS (hazard ration (HR) 1.21; 95% CI: 1.11-1.33, P < 0.001) and [La^-]_b concentrations at 10 min into recovery (HR 0.54; 95% CI: 0.33-0.85, P = 0.01) were significant independent predictors of an adverse event. Transient myocardial ischaemia is associated with a significant elevation in [La^-]_b concentrations, which extends into the recovery period, compared to NI responders. A blunted metabolic response to dobutamine stress and attenuated longitudinal myocardial mechanics are independently associated with short-term adverse events.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144208109","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":"Effect of prolonged voluntary wheel running on oxidative stress and defence mechanisms in cortex and hippocampus of healthy female rats.","authors":"Camilla Myrup Holst, Iria Esperon-Abril, Frederik Bryske Juhl, Jesper Emil Jakobsgaard, Jonas B Kristiansen, Kristian Vissing, Tinna Stevnsner","doi":"10.1113/EP092815","DOIUrl":"https://doi.org/10.1113/EP092815","url":null,"abstract":"<p><p>Physical exercise promotes brain health and cognitive function possibly through mechanisms that include strengthened resistance to oxidative stress. However, limited research has explored the cumulative effects of regular voluntary exercise on both oxidative stress and defence mechanisms in hippocampus and cortex, two regions essential for cognitive function. Especially, adaptations in the young, healthy brain are insufficiently understood. This study investigates the impact of 8 weeks of voluntary wheel running on oxidative damage and counteracting defence mechanisms in the cortex and hippocampus of young, healthy female rats. To this end, we assessed oxidative damage to proteins and DNA, antioxidant defence, and DNA repair mechanisms, focusing on the base excision repair pathway. Our findings show that 8 weeks of voluntary exercise does not significantly modify oxidative damage or antioxidant defences in either cortical or hippocampal brain regions. Instead, the voluntary wheel running intervention led to a reduction in the levels of DNA polymerase β and mitochondrial apurinic/apyrimidinic endonuclease 1, key enzymes involved in base excision repair. Moreover, mitochondrial DNA copy number increased in the cortex, but decreased in the hippocampus, suggesting distinct regional adaptations. Collectively, these results indicate that the healthy young brain maintains redox homeostasis despite reduced DNA repair capacity. By analysing a comprehensive array of biomarkers in two brain regions, this study addresses gaps in our current knowledge on prolonged training and brain health and provides valuable insights into how regular exercise produces region-specific and shared responses in the healthy state.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144191684","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":"Houston, we have a problem: Coagulation concerns during long-term spaceflight.","authors":"Lewis Fall, Damian M Bailey","doi":"10.1113/EP092740","DOIUrl":"https://doi.org/10.1113/EP092740","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144191685","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 acute effect of two exercise modalities on neurocognitive responses in postmenopausal women: A randomized controlled trial.","authors":"Morgane Le Bourvellec, Nathalie Delpech, Laurent Bosquet, Geoffroy Boucard, Carina Enea","doi":"10.1113/EP092537","DOIUrl":"https://doi.org/10.1113/EP092537","url":null,"abstract":"<p><p>Menopause-related cognitive decline, often worsened by vasomotor symptoms (VMS), might be mitigated by high cardiorespiratory fitness (CRF). Although acute exercise supports neurocognitive function, its effects vary by exercise and individual characteristics. In this study, we investigated the acute effects of isometric resistance exercise (IRE) and high-intensity interval exercise (HIIE) on prefrontal cortex oxygenation and cognitive performance in postmenopausal women and examined the influence of VMS and CRF on these outcomes. A cross-over randomized controlled trial was conducted among 29 women aged 55 ± 3 years. The HIIE session included two sets of 12 × 15 s at 100% maximal aerobic power, and the IRE session included 4 × 2 min at 30% maximal voluntary force. Cognitive functions were evaluated before and after sessions using the MEM-III story recall test (episodic memory), Stroop task (inhibitory control) and n-back task (working memory). Prefrontal cortex oxygenation was assessed by measuring oxyhaemoglobin (ΔHbO₂), deoxygenated haemoglobin (ΔHHb) and total haemoglobin (ΔtHb) concentrations before, during and after each session. No effect of exercise was noted on cognitive performance. However, prefrontal cortex oxygenation increased during HIIE (ΔHbO₂: d = 0.99, p < 0.0001; ΔHHb: d = 0.68, p = 0.018; ΔtHb: d = 0.96, p = 0.001), during IRE (ΔHbO₂: d = 1.2, p = 0.003) and post-HIIE (ΔHbO₂ and ΔtHb: d > 1; p < 0.0001) versus control. CRF positively modulated cognitive and cerebrovascular responses to IRE, whereas VMS showed no influence. IRE and HIIE did not improve cognitive performance in postmenopausal women, but increased prefrontal cortex oxygenation, with sustained effects after HIIE. CRF positively modulated responses, whereas VMS did not, underscoring the importance of maintaining high CRF to support brain health in this population.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144191689","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 role of orexin A in the pathogenesis of ischaemic stroke at high altitude.","authors":"Minxia Zhu, Xu Guo, Jing Guo, Zhaojun Zhang, Kexin Zhang, Yaqi Lei, Yuhe Wang, Haoshuang Zhan","doi":"10.1113/EP092314","DOIUrl":"https://doi.org/10.1113/EP092314","url":null,"abstract":"<p><p>Orexin offers protection against cerebral ischaemia-reperfusion injury, with high altitude playing a key role in modulating its expression. This study aimed to investigate the effect of high altitude on orexin expression and its pathophysiological mechanisms involved in high altitude stroke injury. In this study, changes of orexin expression were observed by simulating hypoxia at different altitudes, and the changes of orexin and its receptor were analysed by constructing a middle cerebral artery occlusion (MCAO) model after high altitude simulation. Finally, the protective effect of orexin on cerebral ischaemia-reperfusion injury was evaluated by exogenous orexin intervention. The results indicated that at an altitude of 4000 m, orexin expression was increased, but then decreased at higher altitudes. Rats exposed to 4000 m hypoxia simulation and MCAO exhibited increased orexin and type 1 receptor expression. Exogenous orexin A administration reduced infarct size, improved microcirculation blood flow in the ischaemic cortex, accelerated blood flow, elevated blood oxygen saturation and mitigated systemic oxidative stress and inflammation. These findings confirm our hypothesis that 4000 m altitude promotes orexin expression, thereby attenuating cerebral ischaemia-reperfusion injury through enhanced microcirculation, reduced oxidative stress and inflammation.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144191690","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 human skeletal muscle cross-bridge model to characterize the role of metabolite accumulation in muscle fatigue.","authors":"John I Hendry, Muhammet Enes Erol, Gwenael Layec, Edward P Debold, Shivendra G Tewari, Anders Wallqvist, Venkat R Pannala","doi":"10.1113/EP092843","DOIUrl":"https://doi.org/10.1113/EP092843","url":null,"abstract":"<p><p>Skeletal muscle fatigue is accompanied by the accumulation of metabolites, such as adenosine diphosphate (ADP), inorganic phosphate (P_i), and protons (H⁺). However, we lack a comprehensive understanding of the contribution of these metabolic changes to the development of muscle fatigue during intense exercise and the underlying mechanisms. To address this gap, we collected data from young adults performing a dynamic (0.75 Hz) plantar flexion exercise to task failure (642 ± 104 s), including in vivo concentrations of metabolites and H⁺ measured by ³¹P magnetic resonance spectroscopy as well as muscle activation signals obtained via electromyography. Using these data, we developed and validated a human skeletal muscle model. Our model-based simulations suggested that to continue the plantar flexion exercise at the required power output, muscle activation should progressively increase. In the absence of this increased activation, we observed a reduction in force-generating capacity due to metabolite-mediated inhibition of actin-myosin cross-bridge cycling. Our simulations also showed that P_i reduced force production by 30% when we increased it 50% above the concentrations measured experimentally. A parameter sensitivity analysis suggested that force generation is strongly dependent on the rate of P_i release from the actin-myosin complex, and P_i inhibits force by increasing the rate of actin-myosin detachment. In addition, we proposed an alternative mechanism through which H⁺ might reduce muscle force generation during exercise. In contrast, elevated ADP levels did not significantly affect force generation. This study provides insight into the impact of metabolite accumulation on force generation and muscle fatigue development.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144191683","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":"Physical exercise intervention in glycogen storage disease IIIa: Feasibility and multisystem benefits.","authors":"Asunción Bustos-Sellers, Almudena Montalvo-Pérez, Araceli Boraita, Gonzalo Saco-Ledo, Lidia B Alejo, David Barranco-Gil, Pedro L Valenzuela, Nerea López-Maldonado, Roser Ferrer-Costa, Javier Esparcia-Estrela, Celia Monteagudo-López, Tomàs Pinós, Alejando Santos-Lozano, Alejandro Lucia, Alfredo Santalla","doi":"10.1113/EP092644","DOIUrl":"https://doi.org/10.1113/EP092644","url":null,"abstract":"<p><p>Glycogen storage disease III (GSD-III) is caused by an inherited deficiency of the glycogen debranching enzyme. Affecting the liver, muscle and heart, GSD-IIIa is the most common GSD-III subtype. We evaluated the feasibility and safety of a physical exercise intervention in patients with GSD-IIIa and its effects at the multisystem level. Nine patients (four female; five children and four adults; 60% of all diagnosed Spanish patients) participated in a 12 week home-based, remotely supervised programme combining moderate-intensity endurance and resistance exercises. Training tolerance/adaptation (fatigue severity scale, wellbeing questionnaire) and safety were assessed throughout the intervention period. The following outcomes were determined at baseline and postintervention: Health-related quality of life; muscle, liver, kidney and cardiac damage/function biomarkers; dual X-ray absorptiometry-determined fat/muscle/bone mass; echocardiography-determined cardiac dimensions and left ventricular global longitudinal strain; endurance capacity indicators during cardiopulmonary exercise testing; and muscle strength. The patients completed a median of 88% (interquartile range, 87%-100%) of the prescribed sessions. The intervention was safe and well tolerated, with no changes in wellbeing over time and with a decrease in perceived fatigue severity during the intervention (p = 0.002). Barring alanine aminotransferase, there were no changes in blood biomarkers, and the following significant effects were found at postintervention: Decrease in visceral adipose tissue (p = 0.038); healthier cardiac geometry [from concentric to normal remodelling, with decreases in relative (p = 0.015) and posterior (p = 0.042) wall thickness]; and increases in peak oxygen uptake (p = 0.033), peak power output (p = 0.017) and knee-extension isometric strength (p = 0.012). Although more research is needed, the present findings suggest that exercise should be considered in GSD-IIIa management.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144191687","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}