American journal of physiology. Regulatory, integrative and comparative physiology最新文献

{"title":"Chronic intermittent hypoxia and ovariectomy exert independent and region-specific effects on ΔFosB expression and increase blood pressure in female rats.","authors":"Cephas B Appiah, Joel T Little, George E Farmer, Rebecca L Cunningham, J Thomas Cunningham","doi":"10.1152/ajpregu.00301.2024","DOIUrl":"10.1152/ajpregu.00301.2024","url":null,"abstract":"<p><p>Chronic intermittent hypoxia (CIH), a preclinical model of hypoxemia associated with sleep apnea, causes hypertension associated with increased sympathetic activity linked to arterial chemoreflex and renin-angiotensin system activation. In some models of CIH, ovarian hormones have a protective effect against the change in blood pressure. We tested the effects of CIH and ovariectomy (OVX) on blood pressure and ΔFosB expression in female Sprague-Dawley rats. We hypothesized that CIH and OVX would increase ΔFosB in central autonomic regions associated with increases in blood pressure. Intact (INT) and OVX adult female Sprague-Dawley rats were exposed to 7 days of CIH only during the light (sleep) phase or continuous normoxia (CON). Mean arterial pressure (MAP) was continuously monitored by radiotelemetry. Rats were anesthetized with Inactin and euthanized, and brains were collected and processed for immunohistochemistry. CIH increased MAP relative to CON during the light phase, regardless of gonadal status. During the dark (active) phase, an increase in MAP was observed in OVX but not in INT rats, irrespective of CIH. CIH significantly increased ΔFosB immunoreactive cells in the caudal nucleus of the solitary tract, A5 region, and rostral ventrolateral medulla regardless of OVX. Independent of CIH, OVX significantly increased ΔFosB immunoreactive cells in the organum vasculosum of the lamina terminalis, median preoptic nucleus, rostral nucleus tractus solitarius, and the dorsal, medial, and lateral parvocellular subdivisions of the paraventricular nucleus. Our data indicate that CIH and OVX increase blood pressure independently and exert region-specific effects on ΔFosB immunoreactivity in central autonomic regions.<b>NEW & NOTEWORTHY</b> We investigated the effects of ovarian hormone depletion and chronic intermittent hypoxia (CIH) on blood pressure and ΔFosB staining in central autonomic regions. Our findings indicate that ovariectomy (OVX) and CIH have independent effects on blood pressure and produce region-specific changes in ΔFosB staining in the central autonomic regions associated with hypertension. This suggests that the effects of CIH and OVX on ΔFosB staining and hypertension are not additive.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R36-R54"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144085651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distal skin temperature is reduced in individuals with trait vulnerability to stress-related sleep disturbance.","authors":"Jeremy A Bigalke, Anna M Murvich, R Matthew Brothers, Jason R Carter","doi":"10.1152/ajpregu.00053.2025","DOIUrl":"10.1152/ajpregu.00053.2025","url":null,"abstract":"<p><p>Vulnerability to sleep disturbance following stress (i.e., sleep reactivity) is associated with incident insomnia, though the underlying physiological mechanisms remain unknown. We examined skin temperature stress responsiveness in individuals with high (HSR) versus low (LSR) sleep reactivity. We hypothesized that individuals with HSR would exhibit exaggerated reductions in distal skin temperature during stress. Twenty-eight adults with LSR (5 M/9 F; age: 21 ± 4 yr; BMI: 24 ± 4 kg/m²) and HSR (5 M/9 F; age: 22 ± 4 yr; BMI: 23 ± 3 kg/m²) participated after completing the Ford Insomnia Response to Stress Test (FIRST). Participants wore a water-perfused suit, which was continuously circulated with 34°C water and covered proximal body regions. All participants underwent a Trier Social Stress Test (TSST), which included baseline, speech preparation, speech delivery, and mental arithmetic phases followed by a recovery period. Distal and proximal skin temperature were monitored throughout the testing session. Skin temperature reactivity did not differ between groups. However, a group effect was observed whereby distal skin temperature was reduced by ∼2°C in the HSR compared with the LSR group at all timepoints. Similarly, upper and lower limb distal-proximal gradients (DPGs) were ∼1-2°C lower in the HSR group (i.e., colder extremities). Higher FIRST scores were associated with more negative DPG (<i>r</i> = 0.416-0.578). Despite similar reactivity profiles, individuals with HSR exhibit reduced distal skin temperature, the extent of which was proportional to sleep reactivity severity. These findings suggest that differences in distal skin temperature may be a physiological marker of greater vulnerability to stress-related sleep disturbances in individuals with HSR.<b>NEW & NOTEWORTHY</b> Before sleep, distal skin temperature (i.e., blood flow) increases, facilitating core body temperature reductions that coincide with sleep onset timing. This study investigated whether distal skin temperature at rest and in response to stress differ in individuals with trait susceptibility to stress-related sleep disruption (i.e., high sleep reactivity). Our findings suggest that reduced skin temperature, particularly in distal regions, may represent a physiological marker characterizing interindividual vulnerability to sleep disturbance and insomnia development.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R1-R12"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144109384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Is It the Heat or the Strain? Understanding Risk and Resilience in Heat-Exposed Laborers.","authors":"Kevin O Murray, Orlando Laitano","doi":"10.1152/ajpregu.00137.2025","DOIUrl":"https://doi.org/10.1152/ajpregu.00137.2025","url":null,"abstract":"","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144324177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Change in Tone on the Change in Tone during Exercise: The Growing Story of Functional Sympatholysis in Humans.","authors":"Brett S Kirby, Christopher M Hearon","doi":"10.1152/ajpregu.00143.2025","DOIUrl":"https://doi.org/10.1152/ajpregu.00143.2025","url":null,"abstract":"","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144309364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tumor necrosis factor-alpha in mediation of acute salt loading induced natriuresis in mice; evidence for its physiological role in regulating kidney function.","authors":"Dewan S A Majid, Alexander Castillo","doi":"10.1152/ajpregu.00253.2024","DOIUrl":"https://doi.org/10.1152/ajpregu.00253.2024","url":null,"abstract":"<p><p>Tumor necrosis factor-alpha (TNF-α) exerts natriuresis via activation of its receptor type 1 in the kidney. Although chronic high salt (HS) intake produces this cytokine by immune activation of the mononuclear phagocyte cells, it has not yet been examined whether acute salt loading produces this cytokine and can induce consequent natriuresis. Here, we measured the changes in plasma level and urinary excretion rate of TNF-α (U_TNFαV) during intravenous infusion of isotonic saline (0.9% NaCl), first at euvolemic conditions (3 µL/min for 60 min; Baseline period) and then at an enhanced infusion rate (12 µL/min for 90 min; Salt-loading period) in control mice (n=7) and TNF-α inactivator, etanercept (ETN; 0.5 mg/kg intraperitoneally once daily for 3 days prior to the experiment day; n=7) treated mice. TNF-α concentration in samples were determined using ELISA kit (Bioscience, Woburn, MA). During Baseline period, TNF-α level in plasma was undetected but it increased during salt-loading period in both control (3.7±1.3 pg/mL) and ETN treated (3.3±1.2 pg/mL) mice. In control mice, the baseline U_TNFαV was minimal (0.01±0.002 pg/min/g) but increased to 0.1±0.03 pg/min/g (P<0.05) with associated increase in urinary sodium excretion (U_NaV; 0.5±0.2 to 4.8 ±1.2 µmol/min/g; P<0.05) during salt-loading period. In ETN treated mice, both the U_TNFαV (0.01±0.004 to 0.02±0.01 pg/min/g) and U_NaV (0.4±0.6 to 1.1±0.3 µmol/min/g) responses to salt-loading were markedly attenuated. These findings demonstrate that TNF-α contributes to saline induced natriuresis, suggesting a physiological role for this cytokine in regulating renal excretory function during acute salt loading.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144293212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Focus on \"The Organum Vasculosum of the Lamina Terminalis Contributes to Neurohumoral Mechanisms of Renal Vascular Hypertension\".","authors":"Camila F Roncari, Richard B David","doi":"10.1152/ajpregu.00039.2025","DOIUrl":"https://doi.org/10.1152/ajpregu.00039.2025","url":null,"abstract":"","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144293210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE IMPACT OF ADULT AND LIFELONG HYPOXIA ON VENTRICLE PHENOTYPE IN ZEBRAFISH (<i>DANIO RERIO</i>).","authors":"Brandt Smith, Gil Martinez-Bautista, Steven Williams, Warren W Burggren, Dane A Crossley","doi":"10.1152/ajpregu.00033.2025","DOIUrl":"https://doi.org/10.1152/ajpregu.00033.2025","url":null,"abstract":"<p><p>Hypoxia occurs naturally in a wide range of aquatic ecosystems. However, the physiological and morphological effects of prolonged hypoxia on organ systems remain poorly understood, especially in the cardiovascular system of fishes. We assessed contractile force of isolated hearts from adult zebrafish from control conditions (PO₂ = 21kPa), from adults after a 4-week exposure to hypoxia (PO₂ = 10kPa), or from adults exposed to lifelong hypoxia (PO₂ = 10kPa) throughout development, from egg to adult. Isolated ventricle contractility measurements were conducted during two challenges: increasing stimulation frequency (force-frequency) and during acute hypoxia exposure. All contractile parameters were at least 35% greater in lifelong hypoxic fish compared to control fish while heart mass was significantly smaller in lifelong hypoxic fish compared to controls. However, there were no differences in in the response to force-frequency protocol or graded acute hypoxia. Thickness of the ventricle's compact myocardium was increased ~35% by lifelong hypoxia but not by 4 weeks of hypoxia as adults compared to the control fish. Further, mitochondrial abundance did not significantly change. Collectively, these data suggest that early life hypoxia has major effects on remodeling cardiac tissue and performance in zebrafish.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144293211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Influence of Aortic Compliance on Pulsatile Cerebral Blood Flow in Young Healthy Men: Insight from Endurance Training Intervention.","authors":"Tsubasa Tomoto, Hiroshi Kumagai, Takashi Tarumi, Jun Sugawara","doi":"10.1152/ajpregu.00038.2025","DOIUrl":"https://doi.org/10.1152/ajpregu.00038.2025","url":null,"abstract":"<p><p>Aortic compliance reflects the ability to buffer arterial pulsations generated by the left ventricle (LV) and attenuate pulsatile cerebral blood flow (CBF). Endurance training is associated with increased stroke volume (SV) and enhanced LV systolic function, potentially increasing arterial pulsations to the brain. This study investigated the contribution of aortic compliance to the heart-brain hemodynamic interaction, providing insights from endurance training intervention and lower body negative pressure (LBNP) stimulus. Ten male collegiate tennis players underwent an eight-month endurance training program to improve cardiac function. SV and LV systolic function were measured using echocardiography and applanation tonometry. Pulsatile cerebral blood velocity in the middle cerebral artery was assessed by transcranial Doppler. Aortic compliance was calculated as the ratio between estimated SV via Modelflow and aortic pulse pressure via transfer function from radial arterial pressure. The release of -30 mmHg LBNP was used to initiate a rapid recovery of limited venous return and consequent increases in SV and CBF to assess dynamic recovery slopes. Endurance training increased SV, LV systolic function, and aortic compliance at rest, whereas pulsatile CBF was unchanged. The recovery slopes of SV and aortic compliance were steeper after endurance training, while the slopes of pulsatile CBF remained similar. The change in the slope of aortic compliance was negatively correlated with the change in the slope of pulsatile CBF (r=-0.758, P=0.011). These results suggest that improved aortic compliance after endurance training may accommodate increased SV and LV systolic function and buffer potential increases in arterial pulsations to the brain.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence for potentiation in sympathetic neurovascular transduction following exercise in normotensive adults.","authors":"Massimo Nardone, Julian C Bommarito, Kathryn N Pfundt, Samuel Amanual, Yeshale Chetty, Philip J Millar","doi":"10.1152/ajpregu.00084.2025","DOIUrl":"https://doi.org/10.1152/ajpregu.00084.2025","url":null,"abstract":"<p><p>Following a single bout of dynamic exercise, vascular conductance increases while sympathetic nerve traffic appears unchanged. Discordance between vascular and sympathetic responses may reflect modulation in vasoconstrictor responsiveness. The primary objective was to evaluate sympathetic neurovascular transduction following cycling exercise. The secondary objective was to explore mechanisms contributing to altered sympathetic neurovascular transduction by manipulating limb vascular conductance using local heating of the foot. We hypothesized that sympathetic neurovascular transduction would decrease following cycling exercise but would be unchanged by lower limb heating. Sixteen adults (22 ± 3 years; 43 ± 8 mL/kg/min; 8 female) underwent measurements of heart rate (electrocardiography), mean arterial pressure (MAP; photoplethysmography), muscle sympathetic nerve activity (MSNA; microneurography), and femoral vascular conductance (FVC; Duplex ultrasound) across 3 interventions: cycling exercise (60-min, 60%VO_2peak, n=16), time-control (60-min, n=16), and lower limb heating (foot submersion into 40°C water, n=9). MSNA-FVC transduction was quantified using signal averaging. Compared to control, exercise did not alter MSNA (<i>P</i>=0.72), but increased FVC (<i>P</i><0.01) and MSNA-FVC transduction (-8.6 ± 4.5 vs. -15.1±5.7 mL/min/100mmHg; <i>P</i><0.01). Compared to exercise, heating did not alter MSNA (<i>P</i>=0.71) and tended evoke larger increases in resting FVC (<i>P</i>=0.09). However, increases in MSNA-FVC transduction following exercise tended to persist when compared to heating (-8.7 ± 8.0 vs. -15.1 ± 5.9 mL/min/100mmHg; <i>P</i>=0.06). Contrary to our hypothesis, these findings provide evidence for potentiated sympathetic neurovascular transduction following acute cycling exercise in healthy adults. The observed increase in neurovascular transduction appears independent of resting vasomotor tone.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isolating the effects of iterative cold exposure on metabolic heat production and hypothermia risk.","authors":"Billie K Alba, Afton D Seeley","doi":"10.1152/ajpregu.00095.2025","DOIUrl":"https://doi.org/10.1152/ajpregu.00095.2025","url":null,"abstract":"","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144245913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}