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http://hdl.handle.net/11375/30363
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DC Field | Value | Language |
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dc.contributor.advisor | Scott, Graham | - |
dc.contributor.author | Garvey, Kayla | - |
dc.date.accessioned | 2024-10-04T19:44:14Z | - |
dc.date.available | 2024-10-04T19:44:14Z | - |
dc.date.issued | 2024 | - |
dc.identifier.uri | http://hdl.handle.net/11375/30363 | - |
dc.description.abstract | High-altitude hypoxia constrains tissue O2 supply, but several high-altitude populations have evolved adaptations to overcome this challenge. Evolved increases in hemoglobin-O2 (Hb-O2) affinity are pervasive across high-altitude taxa, but the influence of such increases on aerobic capacity in hypoxia remains contentious. The influence of Hb-O2 affinity on aerobic capacity in hypoxia could vary depending on other traits in the O2 transport pathway, but this possibility is poorly understood. We examined this issue in deer mice (Peromyscus maniculatus), which is found from sea level to >4300m altitude in the Rocky Mountains. Mice from populations native to high- and low-altitude were born and raised to adulthood in captivity. Low-altitude mice (n=14) were acclimated to warm normoxia, and high-altitude mice (n=14) were acclimated to cold hypoxia for 6 weeks, creating two groups with distinct capacities for O2 transport in hypoxia. Aerobic capacity for thermogenesis (VO2max) was measured in hypoxia after each of three pharmacological treatments to manipulate Hb-O2 affinity: saline (control); efaproxiral, which decreases Hb-O2 affinity; and sodium cyanate, which increases Hb-O2 affinity. Our findings suggest that high-altitude deer mice have an adaptive increase in optimal Hb-O2 affinity and SaO2 that likely contributes to greater aerobic capacities in hypoxia. We also suggest that high Hb-O2 affinity adaptations are species, population, and context specific and highlight the importance of the coordinated changes across the oxygen transport pathway that are needed to take advantage of such increases in affinity. | en_US |
dc.language.iso | en | en_US |
dc.subject | Hypoxia | en_US |
dc.subject | Adaptation | en_US |
dc.subject | Hemoglobin | en_US |
dc.subject | Pharmacology | en_US |
dc.subject | Aerobic Capacity | en_US |
dc.title | The Influence of Hemoglobin-Oxygen Affinity on Aerobic Capacity in High Altitude Deer Mice (Peromyscus Maniculatus) | en_US |
dc.type | Thesis | en_US |
dc.contributor.department | Biology | en_US |
dc.description.degreetype | Thesis | en_US |
dc.description.degree | Master of Science (MSc) | en_US |
dc.description.layabstract | High altitude is one of the most extreme environments due to extremely cold temperatures and low levels of oxygen. Many high-altitude species have overcome these challenges by increasing hemoglobin-oxygen affinity but the effect that this has on aerobic capacity is not clear. We tested the effects of pharmacologically manipulating hemoglobin-oxygen affinity on aerobic capacity in high- and low-altitude deer mice. Adult mice born and raised in the captivity were acclimated to their natural environments and treated with drugs to increase or decrease hemoglobin-oxygen affinity. Aerobic capacity and tissue phenotypes were then measured. Our findings suggest that the relationship between hemoglobin-oxygen affinity and aerobic capacity in hypoxia is different between high and low-altitude mice. We suggest that increases in hemoglobin-oxygen affinity are only beneficial if the animal has adaptive increases in the ability to extract and consume oxygen at the level of the tissue. | en_US |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Garvey_Kayla_M_August2024_MSc.pdf | 957.71 kB | Adobe PDF | View/Open |
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