American Journal of Physiology. Regulatory, Integrative and Comparative Physiology This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Evolved Changes in Phenotype Across Skeletal Muscles in Deer Mice Native to High Altitude
We examined this issue in deer mice (Peromyscus maniculatus). Mice derived from both high-altitude and low-altitude populations were born and raised in captivity and then acclimated as adults to normoxia or hypobaric hypoxia (12 kPa O2 for 6-8 weeks). Maximal activities of citrate synthase (CS), cytochrome c oxidase (COX), β-hydroxyacyl-CoA dehydrogenase (HOAD), hexokinase (HK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) were measured in 20 muscles involved in shivering, locomotion, body posture, ventilation, and mastication. Principal components analysis revealed an overall difference in muscle phenotype betwe...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - February 19, 2024 Category: Physiology Authors: Emily J Garrett Srikripa K Prasad Rena M Schweizer Grant B McClelland Graham R Scott Source Type: research

Seasonal fluctuations in BDNF regulate hibernation and torpor in golden-mantled ground squirrels
In this study, we characterized regional changes in BDNF with hibernation, hypothermia, and seasonal cycle in GMGS. Analysis of BDNF protein concentrations by ELISA revealed overlapping seasonal patterns in the hippocampus and hypothalamus, where BDNF levels were highest in summer and lowest in winter. BDNF is the primary ligand for receptor tyrosine kinase B (TrkB), and BDNF/TrkB signaling in the brain potently regulates energy expenditure. To examine the functional relevance of seasonal variation in BDNF, hibernating animals were injected with the small molecule TrkB agonist 7,8-dihydroxyflavone (DHF) daily for 2wk. Comp...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - February 12, 2024 Category: Physiology Authors: Caterina M Hernandez Gregory L Florant Alexis M Stranahan Source Type: research

Effects of hyperventilation on repeated breath-holding while in a fasting state: do risks outweigh the benefits?
CONCLUSION: In a fasted state, pre-apnea hyperventilation compared to normal breathing leads to longer apneas, but may increase the susceptibility to a hypoxic blackout.PMID:38314699 | DOI:10.1152/ajpregu.00260.2023 (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - February 5, 2024 Category: Physiology Authors: Antonis Elia Mikael Gennser Ola Eiken Michail E Keramidas Source Type: research

Modulatory Effects of Estrous Cycle on Ingestive Behaviors and Energy Balance in Young Adult C57BL/6J Mice Maintained on a Phytoestrogen-Free Diet
Am J Physiol Regul Integr Comp Physiol. 2024 Jan 29. doi: 10.1152/ajpregu.00273.2023. Online ahead of print.ABSTRACTThe estrous cycle is known to modify food, fluid, and electrolyte intake behaviors and energy homeostasis in various species, in part through fluctuations in estrogen levels. Simultaneously, commonly commercially available rodent dietary formulations greatly vary in soy protein content, and thereby the delivery of biologically active phytoestrogens. To explore the interactions among the estrous cycle, sodium, fluid, and caloric seeking behaviors, and energy homeostasis, young adult C57BL/6J female mice were m...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 29, 2024 Category: Physiology Authors: John J Reho Patricia C Muskus Darby M Bennett Connie C Grobe Colin M L Burnett Pablo Nakagawa Jeffrey L Segar Curt D Sigmund Justin L Grobe Source Type: research

Diet-induced obesity does not exacerbate cachexia in male mice bearing Lewis-Lung Carcinoma tumors
CONCLUSION: Atrophy was not greater despite larger tumor burden in animals fed an HFD, and RNAseq data suggests partial protection is mediated through differences in mitochondrial function and protein degradation, which may serve as future mechanistic targets.PMID:38252513 | DOI:10.1152/ajpregu.00208.2023 (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 22, 2024 Category: Physiology Authors: Anna G Beaudry Michelle L Law Kayla R Gilley-Connor Hailey Buley Cory M Dungan Carla Manuela Crispim Nascimento Elisabeth G Vichaya Michael P Wiggs Source Type: research

The effects of carbohydrate availability on cycling endurance at the maximal lactate steady state
Am J Physiol Regul Integr Comp Physiol. 2024 Jan 15. doi: 10.1152/ajpregu.00178.2023. Online ahead of print.ABSTRACTThe impacts of carbohydrate (CHO) availability on time to task failure (TTF) and physiological responses to exercise at the maximal lactate steady state (MLSS) have not been studied. Ten participants (3 females, 7 males) completed this double blinded, placebo-controlled study that involved a ramp incremental test, MLSS determination, and four TTF trials at MLSS, all performed on a cycle ergometer. Using a combination of nutritional (CHO [7g/kg] and placebo [PLA; 0g/kg] drinks) and exercise interventions (no e...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 15, 2024 Category: Physiology Authors: Colton P Quinn Rachel M McDougall Saied Jalal Aboodarda Juan M Murias Martin J MacInnis Source Type: research

Short-term dynamic characteristics of diuresis during exogenous pressure perturbations with and without arterial baroreflex control
In conclusion, NMA contributed to the slow component, and its magnitude was approximately one-third that of the effect of PD.PMID:38223938 | DOI:10.1152/ajpregu.00229.2023 (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 15, 2024 Category: Physiology Authors: Toru Kawada Hiroki Matsushita Shohei Yokota Yuki Yoshida Masafumi Fukumitsu Joe Alexander Keita Saku Source Type: research

Adipose biopsy techniques for studies in human exercise physiology
Am J Physiol Regul Integr Comp Physiol. 2024 Jan 15. doi: 10.1152/ajpregu.00266.2023. Online ahead of print.ABSTRACTAdipose biopsy techniques are relatively undefined for exercise physiology research in individuals at or near normal weight. The purpose of this study was to compare the influence of two adipose biopsy techniques on tissue quality through measurements of adipocyte cell size, as well as mRNA and protein levels of select pro- and anti-inflammatory cytokines and adipokines. Thirteen participants (9M, 4W; 28±4 y; 27±3 kg•m-2; VO2max: 3.3±0.7 L•min-1) underwent subcutaneous adipose biopsies on either side o...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 15, 2024 Category: Physiology Authors: Colleen E Lynch Anna R Brandt Caroline S Vincenty Ethan Robbins Chad Skiles Kiril Minchev Toby L Chambers Alicia Belangee Todd A Trappe Scott W Trappe Source Type: research

Combined effects of mild hypothermia and nitrous-oxide-induced narcosis on manual and cognitive performance
Am J Physiol Regul Integr Comp Physiol. 2024 Mar 1;326(3):R197-R209. doi: 10.1152/ajpregu.00246.2023. Epub 2024 Jan 8.ABSTRACTDivers are at enhanced risk of suffering from acute cognitive deterioration because of the low ambient temperatures and the narcotic action of inert gases inspired at high pressures. Yet, the behavioral effects of cold and inert gas narcosis have commonly been assessed in isolation and during short-term provocations. We therefore evaluated the interactive influence of mild hypothermia and narcosis engendered by a subanesthetic dose of nitrous oxide (N2O; a normobaric intervention analog of hyperbari...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 8, 2024 Category: Physiology Authors: Maaike I Moes Antonis Elia Mikael Gennser Michail E Keramidas Source Type: research

Immunohistochemical and ultrastructural characterization of the inner ear epithelial cells of splitnose rockfish ( < em > Sebastes diploproa < /em > )
This study provides a systematic characterization of the cell types in the inner ear of splitnose rockfish (Sebastes diploproa). Scanning electron microscopy revealed the apical morphologies of the six inner ear cell types. Additionally, immunostaining and confocal microscopy characterized the expression and subcellular localization of the proteins Na+/K+-ATPase, carbonic anhydrase, V-type H+-ATPase, Na+-K+-2Cl--Co-Transporter, Otolith Matrix Protein 1, and Otolin-1 in six inner ear cell types bordering the endolymph. This fundamental cytological characterization of the rockfish inner ear epithelium illustrates the intrica...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 8, 2024 Category: Physiology Authors: Garfield Tsz Kwan Leonardo R Andrade Kaelan J Prime Martin Tresguerres Source Type: research

Combined effects of mild hypothermia and nitrous-oxide-induced narcosis on manual and cognitive performance
Am J Physiol Regul Integr Comp Physiol. 2024 Jan 8. doi: 10.1152/ajpregu.00246.2023. Online ahead of print.ABSTRACTDivers are at enhanced risk of suffering from acute cognitive deteriorations, due to the low ambient temperatures, and the narcotic action of inert gases inspired at high pressures. Yet, the behavioral effects of cold and inert-gas narcosis have commonly been assessed in isolation, and during short-term provocations. We, therefore, evaluated the interactive influence of mild hypothermia and narcosis engendered by a subanaesthetic dose of nitrous oxide (N2O; a normobaric intervention analogue of hyperbaric nitr...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 8, 2024 Category: Physiology Authors: Maaike I Moes Antonis Elia Mikael Gennser Michail E Keramidas Source Type: research