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

{"title":"Modeling COPD in <i>Drosophila melanogaster</i> by cigarette smoke inhalation: functional changes and alterations in the expression of COPD-relevant orthologous genes.","authors":"Periklis Marnas, Stefan Lüpold, Lydia Giannakou, Athanasios-Stefanos Giannopoulos, Chrissi Hatzoglou, Konstantinos I Gourgoulianis, Sotirios G Zarogiannis, Erasmia Rouka","doi":"10.1152/ajpregu.00056.2025","DOIUrl":"10.1152/ajpregu.00056.2025","url":null,"abstract":"<p><p>Chronic obstructive pulmonary disease (COPD) ranks as the fourth leading cause of mortality worldwide. Long-term exposure to airway irritants such as smoking and air pollution is the main risk factor for developing the disease. Expanding on previous in silico findings on COPD-relevant orthologous genes between humans and <i>Drosophila melanogaster</i>, we experimentally investigated the contribution of cigarette smoke (CS) inhalation exposure to the induction of COPD-related physiological and transcriptomic modifications. Adult flies 2-4 days old were exposed to CS via inhalation for 20 min over five consecutive days. The metabolic rate, locomotor activity, body mass, total body length, and the expression of COPD-specific genes were measured and compared between the exposed and unexposed groups. CS inhalation exposure significantly increased the metabolic rate and decreased the locomotor activity, body weight, and total body length. Transcriptomic changes were more profound in females, indicating sex-specific differences in CS-induced molecular responses. Functional enrichment analyses of the differentially expressed COPD-relevant genes in females pointed toward ABC transporters, miR-313 microRNA, abnormal developmental rate, DNA repair, and cell differentiation. Our results indicate that <i>D. melanogaster</i> is a powerful model organism for studying the pathophysiological changes associated with COPD. Future work should focus on establishing tracheolar-related changes that would reflect histopathological perturbations similar to COPD patients' airways.<b>NEW & NOTEWORTHY</b> Inhalation exposure of adult <i>D. melanogaster</i> to cigarette smoke induced changes in physiological parameters and the expression of COPD-associated orthologous genes. Transcriptomic responses were more profound in females, indicating sex-specific responses to inhaled toxicants. Furthermore, enrichment analyses of the differentially expressed genes in females pointed to biomolecules associated with response to nicotine and detoxification. <i>D. melanogaster</i> thus provides a powerful model system to test the efficacy of new potential drugs for COPD treatment.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R13-R19"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144109385","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":"G tolerance and vascular sympathetic reflex responses as affected by repeated prolonged exposures to increased force field.","authors":"Ola Eiken, Michail E Keramidas, Antonis Elia, Heather M Bowes, Roger Kölegård","doi":"10.1152/ajpregu.00036.2025","DOIUrl":"10.1152/ajpregu.00036.2025","url":null,"abstract":"<p><p>The capacity to tolerate high G loads in the head-to-seat direction (+Gz tolerance) is critical for pilots flying high-performance aircraft. The adaptive effects of repeated +Gz loading on relaxed +Gz tolerance and G-protective sympathetic reflex pressor responses were investigated. Twelve men were exposed to increased +Gz loads in a relaxed state, during 15 × 40 min sessions across 5 wk. Before and after the training regimen, relaxed +Gz tolerance was investigated during rapid onset-rate (ROR) and gradual onset-rate (GOR) G exposures, and cardiovascular responses were investigated during exposures to 2.5 G in the belly-to-back direction (+Gx) as well as during orthostatic provocations and pressure manipulations of the carotid baroreceptors. The G training increased (<i>P</i> = 0.04) the ROR G tolerance by 17% but did not affect GOR G tolerance, orthostatic tolerance, or the sensitivity and operational pressure range of the carotid baroreflex pressor response. The training reduced (<i>P</i> < 0.001) the arterial pressure response to +Gx exposure. The results suggest that repeated high +Gz exposures do not improve the overall vascular sympathetic response to high +Gz nor the responsiveness of the vascular branch of the carotid baroreflex, but, judging by the arterial pressure responses to +Gx loads, reduces the responsiveness of the vestibulosympathetic reflex. That the G training improved the ROR +Gz tolerance is attributable to local vascular adaptation, in terms of increased stiffness in dependent precapillary vessels resulting from the iterative increments in local transmural pressures.<b>NEW & NOTEWORTHY</b> Five weeks of repeated exposures to head-to-seat directed G load in the relaxed state increased the capacity to tolerate rapid but not gradual G elevations, suggesting unaffected overall vascular sympathetic responses to high G. The G training did not affect the responsiveness of the vascular branch of the carotid baroreflex but reduced the vestibulosympathetic reflex response. The improved tolerance to rapid G elevations is attributable to increased stiffness in dependent precapillary vessels.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R86-R97"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143956273","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 effect of sex on the cardiopulmonary and neuromuscular response to high-intensity interval exercise.","authors":"Hannah K Wilson, Lina Bernert, Padraig Spillane, Emma Squires, Lorna Crawford, Jessica Piasecki, Ross Julian, Eurico N Wilhelm, Kirsty M Hicks, Paul Ansdell","doi":"10.1152/ajpregu.00306.2024","DOIUrl":"10.1152/ajpregu.00306.2024","url":null,"abstract":"<p><p>Sex differences exist in the integrative response to exercise; however, these are typically researched during incremental and constant-load exercise. Interval exercise involves high-intensity efforts interspersed with recovery periods to repeatedly stress physiological systems, and it is currently unknown whether the response to this form of exercise differs between sexes. Ten males and 10 females (age: 25 ± 3 yr) completed two experimental visits. First, an incremental treadmill exercise test was performed to obtain submaximal (lactate threshold) and maximal (V̇o_2peak) data. Thereafter, visit two involved 4 × 3-min running intervals at 90% of the final incremental test velocity (vV̇o_2peak), with 90-s rest between intervals. Before exercise and after each interval, maximal voluntary contraction (MVC), quadriceps potentiated twitch (<i>Q</i>_tw.pot), and voluntary activation (VA) were recorded. The rates of oxygen uptake (V̇o₂), carbon dioxide production (V̇co₂), and ventilation (V̇e) were continuously recorded throughout. There was no sex difference in relative V̇o_2peak (males: 47.2 ± 6.0 vs. females: 44.4 ± 5.8 mL·kg^-1·min^-1, <i>P</i> = 0.292). When expressed relative to peak values, there were no sex differences in the V̇o₂ or V̇co₂ response to the interval task (<i>P</i> ≥ 0.781). Females had greater V̇e/V̇o₂, and V̇e/V̇co₂ values during the first (<i>P</i> ≤ 0.034) and second (V̇e/V̇co₂, <i>P</i> = 0.006) intervals, with a sex × time interaction effect (<i>P</i> ≤ 0.046). There were no sex differences in the reductions in MVC, <i>Q</i>_tw.pot, and VA during the interval task (<i>P</i> ≥ 0.150); however, females had lesser reductions in <i>Q</i>_tw.pot values postexercise (-24 ± 9 vs. -15 ± 8%, <i>P</i> = 0.044). Sex differences exist in the physiological response to interval exercise. Compared with males, females experienced greater hyperpnea during the initial stages, and had lesser decreases in contractile function postexercise.<b>NEW & NOTEWORTHY</b> This study determined that males and females differ in the physiological response to high-intensity interval exercise. Specifically, females had poorer ventilatory efficiency during the first half of the task, but greater knee-extensor fatigue resistance following the task. These data build upon previous observations from constant-load exercise, demonstrating that physiological sex differences are observed during an ecologically valid exercise task commonly prescribed by practitioners in clinical and athletic populations.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R123-R133"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144101190","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":"Comparison of thermoregulatory, cardiovascular, and immune responses to different passive heat therapy modalities.","authors":"Jessica K Atencio, Emma L Reed, Karen Wiedenfeld Needham, Kathryn M Lucernoni, Lindan N Comrada, John R Halliwill, Christopher T Minson","doi":"10.1152/ajpregu.00012.2025","DOIUrl":"10.1152/ajpregu.00012.2025","url":null,"abstract":"<p><p>This study compared thermoregulatory, cardiovascular, and immune responses to acute hot water immersion (HWI), traditional sauna (TRAD), and far infrared sauna (FIR). Twenty healthy adults (10 F; age 24 ± 4 yr) completed three bouts of passive heating: HWI (45 min at 40.5°C), TRAD (3 × 10 min at 80°C), and FIR (45 min at 45-65°C) separated by at least 1 wk. Core temperature (T_c) was measured at baseline and every 5-min during heating. Cardiac output (Q_c) was measured before, halfway, and at the end of heating using the open-circuit acetylene wash-in method. Venous blood was collected at baseline and ∼20-min, 24-, and 48-h postheating for measurement of inflammatory cytokines and immune cell populations. The overall change in T_c from baseline to end of heating was greater in HWI [+1.1°C (0.9, 1.3)] vs. TRAD [+0.4°C (0.2, 0.6), <i>P</i> < 0.01], HWI vs. FIR [+0.0°C (-0.1, 0.2), <i>P</i> < 0.01], and TRAD vs. FIR (<i>P</i> = 0.02). Q_c increased to the greatest extent in HWI [+3.7 L/min (2.9, 4.4)] vs. TRAD [+2.3 L/min (1.8, 2.8), <i>P</i> < 0.01] and HWI vs. FIR [+1.6 L/min (1.2, 2.1), <i>P</i> < 0.01], with no difference between TRAD vs. FIR (<i>P</i> = 0.06). HWI was the only heating modality to elicit inflammatory and immune responses as evidenced by increased interleukin-6 (IL-6) concentration postheating [+0.386 pg/mL (0.093, 0.680), <i>P</i> = 0.04], NK cells 24-h postheating (<i>P</i> = 0.03), and CD8⁺ T cells at 24 (<i>P</i> = 0.02) and 48 h postheating (<i>P</i> = 0.03). A single bout of hot water immersion elicits the greatest thermoregulatory, cardiovascular, and immune responses compared with both sauna modalities.<b>NEW & NOTEWORTHY</b> Our goal was to compare three widely utilized modalities of passive heating in the manner that they are most commonly used for heat therapy. We have demonstrated that hot water immersion leads to the greatest thermoregulatory, cardiovascular, and immune responses compared with both traditional and far infrared saunas in young, healthy adults. Far infrared sauna heating was the least impactful on raising body core temperature and the resulting cardiovascular and immune responses.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R20-R35"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143962645","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 sex on fiber-specific indices of oxidative capacity in human skeletal muscle.","authors":"Celine Bailleul, Nathan Hodson, Sidney Abou Sawan, Dinesh Kumbhare, Daniel R Moore, Jenna B Gillen","doi":"10.1152/ajpregu.00298.2024","DOIUrl":"10.1152/ajpregu.00298.2024","url":null,"abstract":"<p><p>There are reports that females compared to males display increased skeletal muscle oxidative capacity in resting mixed-muscle fiber samples from the <i>vastus lateralis</i>, including markers of mitochondrial content and capillarization. Given that sex comparisons at the mixed-fiber level may be explained by differences in muscle fiber type between males and females, it remains unclear whether the oxidative capacity of type I and/or II fibers differs between sexes. The purpose of this study was to evaluate the influence of sex on fiber-specific indices of mitochondrial content and capillarization in healthy untrained males and females. Resting skeletal muscle samples from eumenorrheic females (<i>n</i> = 14; 23 ± 5 yr; 23.3 ± 3.2 kg/m²) and males (<i>n</i> = 13; 23 ± 4 yr; 23.1 ± 2.4 kg/m²) were analyzed via immunofluorescence staining. There were no sex differences in indices of capillarization (all <i>P</i> > 0.05) or mitochondrial content (all <i>P</i> > 0.05) in type I or type II muscle fibers. However, we observed lower capillary density in type II vs. type I muscle fibers in males (280 ± 66 vs. 364 ± 88 capillaries/mm²; <i>P</i> < 0.001) but not females (335 ± 77 vs. 329 ± 48 capillaries/mm²; <i>P</i> = 0.76), owing to greater cross-sectional area (CSA) of type II vs. type I fibers in males only (males <i>P</i> = 0.03; females <i>P</i> = 0.44). Females compared to males also displayed greater proportionate area of type I fibers (44 ± 12% vs. 31 ± 14%; <i>P</i> = 0.03) and smaller CSA of type IIx fibers (3,033 ± 902 vs. 5,573 ± 1,352 μm²; <i>P</i> = 0.002). Our results suggest that while muscle fiber type composition and size differ between males and females, there are no sex differences in mitochondrial content and capillarization of type I or II muscle fibers in untrained adults.<b>NEW & NOTEWORTHY</b> Research suggests that skeletal muscle oxidative capacity in mixed-fiber muscle homogenates is greater in females than in males. In healthy, untrained individuals, we demonstrate by fiber-specific immunofluorescence that females have a greater proportionate area of type I muscle fibers but no difference in mitochondrial content or capillarization of type I or II fibers compared to males. These findings suggest that although females display a more oxidative fiber type composition, sex does not influence muscle fiber-specific oxidative capacity.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R70-R80"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144132105","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":"SERCA activation prevents Ca²⁺ and ATP upregulation during 3-day soleus muscle unloading in rats.","authors":"Ksenia A Zaripova, Svetlana P Belova, Kristina A Sharlo, Darya A Sidorenko, Tatiana Y Kostrominova, Boris S Shenkman, Tatiana L Nemirovskaya","doi":"10.1152/ajpregu.00177.2024","DOIUrl":"10.1152/ajpregu.00177.2024","url":null,"abstract":"<p><p>The imbalance in the ratio of protein synthesis versus protein degradation results in skeletal muscle atrophy following unloading. The onset of these processes is regulated by the sarcoplasmic concentrations of ATP and calcium (Ca²⁺). We tested the hypothesis that unloading-induced inactivation of sarcoendoplasmic reticulum calcium ATPase (SERCA) results in raised Ca²⁺ concentrations, triggering catabolic processes. CDN1163, an activator of SERCA, was used to test this hypothesis. Three groups of male rats were used: control rats with intraperitoneal injection of placebo (C), 3 days of unloading with placebo injection (3HS), and 3 days of unloading injected with CDN1163 (3HSC). Treatment with CDN1163 during 3 days of soleus muscle unloading prevented the upregulation of Ca²⁺ and ATP and the slow-to-fast shift in muscle fiber composition. This treatment blocked the decrease in the phosphorylation of the anabolic markers [glycogen synthase kinase-3β (GSK3β), eukaryotic translation elongation factor 2 (eEF2), and ribosomal protein S6 (S6, Ser240/244/Ser235/236)], and therefore it is likely that it improved the efficiency of translation in the unloaded muscle, but it did not affect mTORC1-dependent signaling. Treatment with CDN1163 also modulated the regulation of the Ca²⁺-dependent signaling in muscle during unloading via SERCA1 and calsequestrin 2 (CSQ2) and changes in the calcium/calmodulin-dependent protein kinase II (CaMKII) phosphorylation and the content of inositol 1,4,5-trisphosphate receptor (IP3R). In addition, CDN1163 prevented the upregulation of the mRNA expression of muscle-specific RING finger protein 1 (MuRF1) [but not ubiquitin ligase muscle atrophy F-box (MAFbx)] and attenuated the increase of casitas B lymphoma-b (Cbl-b) and ubiquitin mRNA expression during unloading. Activation of SERCA with CDN1163 prevents the upregulation of Ca²⁺ and ATP, as well as calcium-dependent and ubiquitin-proteasome pathways markers, and improves protein translation efficiency in 3-day unloaded soleus muscle.<b>NEW & NOTEWORTHY</b> A hypothesis was tested that unloading-induced inactivation of SERCA results in the accumulation of increased Ca²⁺ concentrations and activation of catabolic processes. CDN1163, an activator of SERCA, was used to test this hypothesis. CDN1163 prevented the decrease in phosphorylation of anabolic markers, which likely improved translation efficiency in unloaded muscle. CDN1163 prevented unloading-induced upregulation of mRNA expression of MuRF1 (but not MAFbx) and attenuated the increase of Cbl-b and ubiquitin mRNA expression.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R108-R122"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144155466","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":"Bodily markers of basic emotions: a thermographic study.","authors":"Danila Shelepenkov, Alfred Essel, Vladimir Kosonogov","doi":"10.1152/ajpregu.00018.2025","DOIUrl":"10.1152/ajpregu.00018.2025","url":null,"abstract":"<p><p>Skin temperature has been recognized as a potential marker of emotional arousal, with studies demonstrating temperature changes in response to various emotional stimuli. However, temperature in different body parts and in different basic emotions has not been studied sufficiently. Our study aimed to investigate whether basic emotions could be reflected in temperature changes at specific body surfaces. Forty healthy subjects viewed blocks of pictures inducing six basic emotions and neutral images while their temperature at the shoulder, throat, chest, and temple was recorded. In addition, electrodermal activity and electrocardiograms were captured as control variables. We showed, first, temperature at the chest, on average, increased, and its change was higher than at other regions. Second, chest temperature increased in various emotions such as fear, surprise, and happiness. Third, chest temperature correlated with heart rate; therefore, it may reflect the cardiac activity. Fourth, temperatures in different regions did not correlate, suggesting a specificity of thermal reactions. Our results revealed associations between specific emotions and temperature changes at different body surfaces. We indicate the need for further research with more specific designs, stronger induction methods, and additional physiological measures, such as facial muscle activity.<b>NEW & NOTEWORTHY</b> We studied whether basic emotions could be reflected in temperature changes at specific body surfaces. Healthy subjects viewed pictures inducing six basic emotions and neutral images with temperature at the shoulder, throat, chest, and temple being recorded. Chest temperature was higher than at other regions and increased in various emotions such as fear, surprise, and happiness. It correlated with heart rate. Temperature in different regions did not correlate, suggesting a specificity of thermal reactions.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R81-R85"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144085650","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":"Gustatory and olfactory-guided responsiveness to maltodextrin solutions in mice.","authors":"Elizabeth A Hamel, Ginger D Blonde, Ellie Williams, Adam Dewan, Alan C Spector","doi":"10.1152/ajpregu.00275.2024","DOIUrl":"10.1152/ajpregu.00275.2024","url":null,"abstract":"<p><p>Rodents avidly consume maltodextrin solutions. Oligosaccharides appear to generate a detectable oral perception distinct from basic tastes in rodents and humans. Mice lacking one or both subunits of the T1R2 + T1R3 heterodimer still display relatively normal preference for maltodextrins but have severely blunted responsiveness to sugars. To test whether taste contributes to maltodextrin responsiveness, we performed lingual gustatory nerve transection (NX) in mice with [wild-type (WT)] and without [knockout (KO)] functional T1R3 subunits. Mice were then tested, after a ∼23-h fast, for concentration-dependent licking responses to Maltrin, a maltodextrin, and sucrose in a brief-access paradigm, which minimizes postingestive influences on responsiveness. Compared with SHAM mice, NX mice displayed blunted lick responses and initiated fewer trials to Maltrin. The KO mice exhibited some concentration-dependent licking to sucrose, though attenuated, which may be due to flavor-nutrient learning across sessions. However, NX blunted this responsiveness in all mice. The results suggest that an intact chorda tympani and/or glossopharyngeal nerve(s) is required for normal licking to maltodextrin and sucrose solutions, confirming a contribution of gustatory signals to behavior. A follow-up experiment tested whether olfactory signals contribute to Maltrin detection in mice trained in a Go/No-Go task. Mice could detect the volatiles associated with Maltrin in a concentration-dependent manner. As maltodextrins have negligible vapor pressure, mice are likely responding to volatile contaminants within the solution, which could potentially serve as cues for flavor-nutrient conditioning. Nevertheless, there is clearly a gustatory component that unconditionally drives hedonic responsiveness to this stimulus.<b>NEW & NOTEWORTHY</b> Maltodextrins have long been believed to be tasteless and odorless and are commonly used in food production. Previous research suggests that maltodextrins elicit a distinct taste, separate from other carbohydrate stimuli like sugars, in both rodents and humans. Our findings provide compelling evidence that ingestive responsiveness to maltodextrins in mice relies on signaling in gustatory nerves. Furthermore, rodents can detect this stimulus via olfaction. Olfactory cues may contribute to flavor-nutrient conditioning when taste is removed.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R55-R69"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144085652","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":"Temperature sensitivity of spreading depolarization in the CNS of <i>Drosophila melanogaster</i>.","authors":"Mads Kuhlmann Andersen, R Meldrum Robertson, Heath A MacMillan","doi":"10.1152/ajpregu.00040.2025","DOIUrl":"10.1152/ajpregu.00040.2025","url":null,"abstract":"<p><p>During exposure to extreme stress, the central nervous system (CNS) of mammals and insects fails through a phenomenon known as spreading depolarization (SD). SD is characterized by an abrupt disruption of ion gradients across neural and glial membranes that spreads through the CNS, silencing neural activity. In humans, SD is associated with neuropathological conditions like migraine and stroke, while it coincides with critical thermal limits for activity in insects. In the latter, SD is conveniently monitored by recording the transperineurial potential (TPP), which we used to explore the plasticity and temperature dependence of SD thresholds and electrophysiological parameters in fruit flies (<i>Drosophila melanogaster</i>). Specifically, we characterized the effects of thermal acclimation on the characteristics of TPP changes during cold-induced SD, after which we induced SD with anoxia at different temperatures in both acclimation groups to examine the interactive effects of temperature and acclimation status. Lastly, we investigated how these affect the rate of SD propagation across the fly CNS. Cold acclimation enhanced resistance to both cold and anoxic SD, and our TPP measurements revealed independent and interactive effects of temperature and acclimation on the TPP and SD propagation. This suggests that thermodynamic processes and physiological mechanisms interact to modulate the thermal threshold for activity through SD and its electrophysiological phenomenology. These findings are discussed in relation to conceptual models for SD and established mechanisms for variation in the thermal threshold for SD, and we emphasize that future comparative or cross-species studies or translations must account for thermodynamic effects to improve inferences based on electrophysiology.<b>NEW & NOTEWORTHY</b> Thermal acclimation induces variation in the temperatures leading to spreading depolarization at the critical thermal limits in invertebrates, but mechanistic inferences based on electrophysiology might be skewed by thermodynamic effects. Here, we quantify the thermal dependence of spreading depolarization parameters in fruit flies, use it to infer mechanisms, and provide perspectives for future comparative research. In addition, we propose <i>Drosophila</i> as a model system to understand this event in vertebrates, including humans.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R134-R149"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144109387","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":"Autonomic responses to exercise and cold pressor test in young healthy Hispanic adults.","authors":"Ashlesha Dilip Dalve, Justo Perez, Ruby Ama Nyarko, Randy Liu, Jasdeep Kaur","doi":"10.1152/ajpregu.00207.2024","DOIUrl":"10.1152/ajpregu.00207.2024","url":null,"abstract":"<p><p>Hispanic/Latino (H/La) individuals have a notably high incidence of type 2 diabetes and obesity, significantly increasing their cardiovascular risk. Although regular exercise reduces the risk of cardiovascular diseases, abnormal hemodynamic responses during exercise can increase the risk of adverse events during/immediately following the exercise bout. To date, no studies have investigated the pressor response to exercise in the H/La population. Therefore, we examined exercise pressor reflex in 48 young healthy adults [22 H/La, 26 non-Hispanic White (NHW)]. Beat-to-beat blood pressure (finger plethysmography) and heart rate (ECG) were measured before and during isometric handgrip (HG) performed at 30% and 40% of their maximal voluntary contraction, followed by postexercise ischemia (PEI) to isolate the muscle metaboreflex. In addition, cold pressor test (CPT) was used to quantify pressor response to a nonexercise sympathoexcitatory stimulus. We observed that increases in mean arterial pressure (ΔMAP) during 30%HG (<i>P</i> = 0.58) and its subsequent PEI (<i>P</i> = 0.93) were not different between the two groups. Likewise, ΔMAP during 40%HG and PEI was similar between both groups (PEI: H/La = 39 ± 8 mmHg, NHW = 37 ± 11 mmHg; <i>P</i> = 0.51). However, the pressor response to CPT was significantly augmented in H/La (ΔMAP: H/La = 31 ± 11 mmHg, NHW = 22 ± 11 mmHg; <i>P</i> = 0.02). Together, these data suggest that the exercise pressor reflex and muscle metaboreflex are not altered in young healthy H/La adults. However, H/La adults exhibit elevated blood pressure reactivity to a nonexercise sympathoexcitatory stimulus, which may be indicative of early autonomic dysregulation in Hispanic adults as compared with NHW adults, potentially contributing to higher cardiovascular risk with aging in the Hispanic population.<b>NEW & NOTEWORTHY</b> This is the first study to investigate exercise-induced cardiovascular responses in young, healthy Hispanic individuals. We found that although the exercise pressor reflex and the muscle metaboreflex are not augmented in Hispanic adults, they exhibit elevated blood pressure reactivity in response to the cold pressor test. This remarkably high pressor response to a nonexercise stimulus potentially predisposes the Hispanic adults to earlier development of future hypertension.</p>","PeriodicalId":7630,"journal":{"name":"American journal of physiology. Regulatory, integrative and comparative physiology","volume":" ","pages":"R98-R107"},"PeriodicalIF":2.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135883","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}