2023-11-17 12:53:12
Un oso grizzly – BOB HUBNER, WSU PHOTO SERVICES
MADRID, 17 Nov. (EUROPA PRESS) –
A genetic study has confirmed that bears’ energy production still rises and falls in a daily pattern even when they sleep for several months without eating.
Researchers at Washington State University also found that during hibernation the amplitude of energy production was reduced, meaning the range of highs and lows was reduced. The peak also occurred later in the day during hibernation than during the active season, but the daily fluctuation was still there.
“This underscores the importance of circadian rhythms themselves: that they give organisms the flexibility to continue functioning in a state as extreme as that of a hibernating bear,” he said. it’s a statement Heiko Jansen, a professor in the department of neuroscience and integrative physiology at WSU and senior author of the study, published in the Journal of Comparative Physiology B.
Other research has shown that circadian rhythms, the 24-hour physical cycles common to most living animals on Earth, have links to metabolic health. In humans, major alterations in these patterns, such as those that occur during night work, They have been linked to metabolic problems such as weight gain and a higher prevalence of diabetes.
In a sense, bears work extreme shifts and take up to six months off when they hibernate. Researchers like Jansen’s team are trying to figure out how they engage in seemingly unhealthy habits of gaining excessive weight and then going without eating. and not move much for several monthsall without harmful effects such as bone loss or diseases such as diabetes.
Unlike hibernating rodents that are almost comatose, bears move occasionally during this period of inactivity. Through observation studies of grizzly bears, researchers found that These movements tend to follow a circadian rhythm with more activity during the day than at night.
In the current study, the researchers They observed whether this circadian rhythm was expressed at the cellular level. They sampled cells from six bears during the active and hibernating seasons and then cultured those cells to perform a series of genetic analyses.
To mimic hibernation, the researchers examined the cells at the low body temperature typical of bears during hibernation. at approximately 34 degrees Celsius and compared it with 37 C during the active season.
They discovered that thousands of genes were rhythmically expressed in hibernating bear cells. This translated into energy rhythms by increasing and decreasing the production of adenosine triphosphate, or ATP, the body’s cellular energy source. ATP was still produced in a daily pattern during hibernation, but production had an attenuated amplitude, lower peaks and troughs. The highest production point was also moved later in the day under hibernation conditions than under active season conditions.
Maintaining a circadian rhythm requires some energy. Researchers believe that altering this rhythm during hibernation may allow bears to still get some energetic benefit from the daily cycle without as much cost, likely helping them survive without food for months.
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