Arctic Ground Squirrel

Scientists Induce Hibernation in Squirrels

Hibernation is an essential survival strategy for some animals and scientists have long thought it could also hold promise for human survival. But how hibernation works is largely unknown. Scientists at the University of Alaska Fairbanks have successfully induced hibernation at will, showing how the process is initiated. Their research is published in the July 26 issue of The Journal of Neuroscience.

A hibernating animal has a reduced heart rate and blood flow similar to a person in cardiac arrest, yet the hibernator doesn’t suffer the brain damage that can occur in people.

“Understanding the neuroprotective qualities of hibernating animals may lead to development of a drug or therapy to save people’s lives after a stroke or heart attack,” said Kelly Drew, senior author and UAF professor of chemistry and biochemistry in the Institute of Arctic Biology.

Hibernating animals survive by severely reducing their metabolism, a condition called torpor, in which oxygen consumption can fall to as low as one percent of resting metabolic rate and core body temperature to near or below freezing temperatures.

Arctic ground squirrels, like all animals and people, produce a molecule called adenosine that slows nerve cell activity.

“When a squirrel begins to hibernate and when you feel drowsy it’s because adenosine molecules have attached themselves to receptors in your brain,” said Tulasi Jinka, lead author and a postdoctoral fellow in Drew’s lab.

The receptors can be regulated by a simple cup of coffee. A caffeine molecule is similar enough in structure to adenosine that it binds to the receptors and effectively stops or reverses the onset of drowsiness. Jinka and Drew wanted to know what substances trip the squirrels’ switch to start to hibernate.

“We devised an experiment in which non-hibernating arctic ground squirrels were given a substance that stimulated adenosine receptors in their brains. We expected the substance to induce hibernation,” Drew said. “We also gave a substance similar to caffeine to arouse hibernating ground squirrels.”

The non-hibernating squirrels were tested three times during one year. They were tested during the summer when they were not hibernating, again early in their hibernation season and a third time midway through the hibernation season. If animals were hibernating before the test, Jinka woke them up to see if the substance would cause them to go back into hibernation. To ensure that his expectations did not influence the results he delivered a placebo in the same manner as the drug and did not know which solution contained the active substance when he conducted the experiments.

UAF Student Ambassadors: Research Perspective: Arctic Ground ...

It is now midday in the Drew lab and experiments have been underway since 8:00am. Tissue samples and their respective proteins are analyzed by a procedure called the Western blot. {I've since heard of methods called the Southern and Northern blots...but no Eastern blot...hmm!} I, personally, have been in what I like to term the "Operating Room". And, yes, with an arctic ground squirrel, another intern, and a graduate student. You might be wondering why such a friendly student like myself would participate in animal research. First, a research lab is kept under strict supervision and all experiments must be approved by the Institutional Animal Care and Use Committee (IACUC). Plus, I treat the squirrels with respect and am grateful for what their amazing biochemistry teaches us. Through the Alaska Native Science and Engineering Program (ANSEP) I saw a presentation about the Drew lab. This was back in 2006, when I was a junior in high school. {Start sprouting connections early!} All these years later I'm finally an intern in the lab. This essentially means that I get paid to learn. My grant money comes from the National Science Foundation, but the opportunity was presented to me by ANSEP. By coincidence, I discovered that this lab collaborates with the Dow Neurobiology Lab in Portland, Oregon. I passed through that city this summer, on my way to a friend's wedding. I arranged to meet a neuroscientist there. We spoke of her research and graduate programs in the area.

Arctic Ground Squirrel

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