University of Saskatchewan

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Photo of Kate Johnson (Photo courtesy of Michelle Berg)
October 19, 2008

U of S student explores link between stress and depression

September 29, 2008

By Anne-Marie Hickey

An estimated two thirds of Canadians know someone who suffers from depression. Yet there is little known about the biological cause of depression and a new antidepressant drug hasn’t been developed in half a century.

University of Saskatchewan second-year physiology student Kate Johnson, who has been named a “researcher of tomorrow” by the college of arts and science, hopes to help shed light on the biological effects of depression and the role stress plays in the disease.

“With depression affecting more than a million Canadians per year, it is vital to keep working to understand the disease and to find a suitable cure,” says Johnson.

The basic research she is doing may help pave the way for a new, faster-acting, antidepressant drug with fewer side-effects.

“If we understand what affects the brain, we can start to fix it and give it the right chemicals, proteins and treatment to help the brain function normally again,” says Johnson, who hopes to pursue a career in medicine.

Johnson is working with supervisor Lisa Kalynchuk, Canada Research Chair in Behavioural Neuroscience. Johnson was paired with Kalynchuk through the researchers of tomorrow program due to her high grade average in high school and her involvement in extra-curricular activities such as volunteering at the Royal University Hospital and running track and field with the Huskies.

Johnson is studying chemical changes in the brain related to stress and depression by studying laboratory rats. To see how stress may be causing symptoms of depression in rats, she examines how stress hormones produce changes in their brains.

The research is important because the current antidepressant drugs are inadequate, says Kalynchuk.

“We haven’t had a new antidepressant drug developed in the last 50 years,” says Kalynchuk. “Prozac isn’t new; it has largely the same mechanism of action as anti-depressant drugs from 50 years ago.”

One reason a new drug hasn’t been developed is because there is little information on the biological cause of depression, says Kalynchuk.

Johnson puts the rats through behavioural tests, such as determining how soon the rats would give up when faced with an obstacle.

“Generally, people with depression are very quick to give up on something. We expect the rats to show the same thing,” says Kalynchuk.

After three weeks, changes to cells in the brain are analyzed. Johnson identifies any chemical changes that have occurred in the hippocampus, a region in the brain that controls memory and emotion.

She can measure stress levels by taking a blood sample, as certain chemicals are elevated in rodents when they are put through stress testing.

Rats are used for testing because researchers are familiar with their behaviour and brain, allowing quick detection of any abnormalities. Rats are easy to handle and respond well to behavioural tasks, making them excellent subjects for the team.

“Although I don’t always like doing experiments using an animal model, I know that everything is being done to help so many people live free from pain and ailment,” says Johnson. “The research community studying psychiatric disorders has already made so much progress and has helped many people in the process.”

An animal care committee on campus, working under the standards of the Canadian Council on Animal Care, requires that students are trained in animal handling. Kalynchuk’s lab must also submit a written protocol on the handling of every animal to ensure animals are cared for properly.

Johnson will be named as an author of an article to be published in an academic journal sometime this fall.

“For a first-year student to get her name on the paper will be encouraging,” says Kalynchuk. “She’ll be proud of that.”

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Anne-Marie Hickey is a student intern for the U of S Research Communications office. Visit www.usask/research for more stories of student research.

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