Characterizing the influence of chronic hypobaric hypoxia on diaphragmatic myofilament contractile function and phosphorylation in high-altitude deer mice and low-altitude white-footed mice
| Autor: | S. A. Lyons, Y. Ding, Graham R. Scott, Todd E. Gillis |
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| Rok vydání: | 2019 |
| Předmět: |
030110 physiology
0106 biological sciences 0301 basic medicine medicine.medical_specialty Myofilament Time Factors Physiology Acclimatization Diaphragm Diaphragmatic breathing 010603 evolutionary biology 01 natural sciences Biochemistry 03 medical and health sciences Peromyscus Endocrinology Myofibrils Species Specificity Internal medicine medicine Animals Myocyte Protein phosphorylation Hypoxia Ecology Evolution Behavior and Systematics Chemistry Altitude Hypoxia (environmental) Effects of high altitude on humans Phosphorylation Calcium Animal Science and Zoology |
| Zdroj: | Journal of Comparative Physiology B. 189:489-499 |
| ISSN: | 1432-136X 0174-1578 |
| DOI: | 10.1007/s00360-019-01224-w |
| Popis: | Deer mice, Peromyscusmaniculatus, live at high altitudes where limited O2 represents a challenge to maintaining oxygen delivery to tissues. Previous work has demonstrated that hypoxia acclimation of deer mice and low altitude white-footed mice (P. leucopus) increases the force generating capacity of the diaphragm. The mechanism behind this improved contractile function is not known. Within myocytes, the myofilament plays a critical role in setting the rate and level of force production, and its ability to generate force can change in response to changes in physiological conditions. In the current study, we examined how chronic hypobaric hypoxia exposure of deer mice and white-footed mice influences the Ca2+ activation of force generation by skinned diaphragmatic myofilaments, and the phosphorylation of myofilament proteins. Results demonstrate that myofilament force production, and the Ca2+ sensitivity of force generation, were not impacted by acclimation to hypobaric hypoxia, and did not differ between preparations from the two species. The cooperativity of the force-pCa relationship, and the maximal rate of force generation were also the same in the preparations from both species, and not impacted by acclimation. Finally, the relative phosphorylation of TnT, and MLC was lower in deer mice than white-footed mice, but was not affected by acclimation. These results indicate that species differences in diaphragm function, and the increase in force production with hypoxia acclimation, are not due to differences, or changes, in myofilament function. However, it appears that diaphragmatic myofilament function in these species is not affected by chronic hypobaric hypoxia exposure. |
| Databáze: | OpenAIRE |
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