Life Lines by Dr. Dolittle

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Tag Archive for ‘hypoxia’

Hypoxia improves exercise duration

Speaking of hypoxia, a new study published in Physiological Reports examined how training for 2 weeks under 18% hypoxia impacts muscles of Thoroughbred horses. Unlike humans, these horses do not increase production of red blood cells to enhance oxygen transport throughout the body under hypoxic conditions. This difference led researchers to speculate that the horses had other ways of adapting to exercise.   In the new study, horses were trained […]

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Cholesterol levels in tissues change during hypoxia in naked mole rats

Naked mole rats are rather famous from a physiological perspective for their amazing ability to live in hypoxic conditions. They do so in part by reducing their metabolic rate. In fact, researchers at the University of Ottawa in Canada showed that reducing environmental oxygen levels to 11% resulted in a 34% decrease in the animal’s metabolic rate. Studies of hypoxia-tolerant goldfish show that the animals respond to hypoxia challenges by […]

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Physiology of diving animals: how do they deal with hypoxia?

Dr. Jose Pablo Vazquez-Medina (pictured at right), a comparative physiologist at the University of California – Berkeley, was scheduled to present several ongoing studies from his lab at the Experimental Biology conference last month. Dr. Vazquez-Medina is a member of the Comparative and Evolutionary Physiology section of the American Physiological Society. Although the conference was cancelled due to Covid-19, Dr. Vazquez-Medina has agreed to share his research with us.   […]

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How some fish may compensate for low environmental oxygen

     Adult fish rely on gills to extract oxygen from the surrounding water. Larval fish, on the other hand, do not have well-developed gills and instead rely primarily on gas exchange across their skin.      In a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, researchers examined whether larval fish could use their pectoral fins to increase the flow of water […]

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Warm hypoxic waters impair heart function in some fish

Events causing bodies of water to become hypoxic (low oxygen levels) are increasing with climate change. Water can become hypoxic when it warms up or there are changes in tidal flow, density, wind patterns as well as separation from the main source, such as occurs in a tidepool. While some fish are tolerant of hypoxia and even anoxia (oxygen depleted) environments others, such as Atlantic cod and steelhead trout, rely […]

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Physiology in Arizona

The Arizona Physiological Society will be hosting their 12th annual meeting Friday and Saturday on the Arizona State University campus. Physiologists from all over the state will be meeting to talk about a variety of topics ranging from comparative physiology to clinical trials. The 2019 Arizona Distinguished Lecturer is Dr. Ralph Fregosi from the University of Arizona in Tucson who specializes in respiratory physiology. The Keynote speaker will be Dr. […]

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Adults are better adapted to survive without oxygen

Adult fruit flies (Drosophila melanogaster) are more tolerant of environments devoid of oxygen than their larvae. In fact, they are able to survive up to 12 hours without oxygen by becoming paralyzed, which enables them to dramatically reduce metabolism and the need for oxygen. In contrast, Drosophila larvae expend a lot of energy trying to escape and are only able to tolerate a couple of hours without oxygen. This is surprising […]

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Remarkable hypoxia and cold tolerance of rodents native to the Tibetan plateau

The plateau zokor (Eospalax baileyi) is an underground dwelling rodent species native to the Tibetan plateau (2000-4200 meters in elevation). A new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology explored how these animals were adapted to extract oxygen from an environment with very low levels (83-88% of atmospheric). Hemoglobin molecules found in red blood cells are responsible for binding oxygen and transporting it to tissues […]

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High altitude deer mice have less stress?

Animals that live at high altitude have evolved a number of physiological adaptations to deal with the low atmospheric oxygen concentrations (hypoxia). For low altitude acclimated animals, short exposures to high altitude results in activation of the sympathetic nervous system (i.e. the fight or flight response). This is a good thing because activation of this system results in more blood flow, especially to the heart and brain to help protect oxygen […]

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Lactate directly increases breathing

Hypoxic environments increase ventilation in animals. This helps to bring in more oxygen when environmental levels may be limited. With limited oxygen availability, the body turns to anaerobic metabolism, resulting in the production of lactate ions. These ions are known to indirectly stimulate breathing by lowering blood pH and were more recently discovered to directly stimulate the carotid body to increase breathing. For this reason, lactate ions are thought to […]

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