babyboos
11-16-2005, 01:48 PM
http://education.guardian.co.uk/higher/news/story/0,,1643434,00.html
A new study suggests hamsters suffer from symptoms of anxiety and depression during the dark days of winter, just as some humans do.
Researchers compared hamsters housed for weeks under winter-like lighting conditions to those who had days with longer daylight. The scientists found more symptoms of depression and anxiety in the first group.
A variety of hamster known as a dwarf hamster.
The study also suggested hamsters born in winter-like light conditions had increased depressive symptoms as adults, according to the researchers.
The findings "may provide some insight into the development of seasonal affective disorders in humans," said Randy Nelson of Ohio State University, a co-author of the study. Nelson and doctoral student Leah Pyter presented the findings Nov. 15 in Washington, D.C. at the annual meeting of the Society for Neuroscience.
The study involved 53 female and 48 male Siberian hamsters.
At about 60 days of age, the hamsters began a series of tests that are used to measure anxiety and depression in the animals. Many of these tests are the same ones used by pharmaceutical companies to test anti-depressive and anti-anxiety drugs in animals before they are used in humans, Nelson said.
Tests for anxiety included one in which hamsters are placed in a large box and viewed for 60 minutes to see how much time they spend in the middle versus near the walls. Anxious hamsters will spend more time along the walls, where they feel more protected, while less anxious animals will explore the entire box.
Among the tests for depression was one in which they measured how much of a sugar drink hamsters drank over the course of several days.
Hamsters generally like this drink, but hamsters with depressive-like symptoms will not drink as much.
"We found that the amount of light hamsters were exposed to prenatally and up through weaning did have enduring effects on behavior in adulthood," Pyter said. "But these effects were tempered quite a bit by whether they spent their time as adults in long days or short days."
Research in humans also suggests people who are born during the winter are more likely to suffer from depression as adults, according to Nelson. The results in hamsters weren't clear-cut, but they did point in a similar direction, the researchers aid. "A lot more work needs to be done," Nelson added.
Also, female hamsters showed more evidence of depression than males, which corresponds to research in humans which shows more depression among women than men, Nelson said.
Pyter said future studies will examine whether drugs used to treat anxiety and depression will reduce seasonal anxiety and depressive- like symptoms in hamsters. Nelson added that they will also look at the role of seasonal changes in stress hormones and brain chemicals in depression and anxiety in hamsters.
A new study suggests hamsters suffer from symptoms of anxiety and depression during the dark days of winter, just as some humans do.
Researchers compared hamsters housed for weeks under winter-like lighting conditions to those who had days with longer daylight. The scientists found more symptoms of depression and anxiety in the first group.
A variety of hamster known as a dwarf hamster.
The study also suggested hamsters born in winter-like light conditions had increased depressive symptoms as adults, according to the researchers.
The findings "may provide some insight into the development of seasonal affective disorders in humans," said Randy Nelson of Ohio State University, a co-author of the study. Nelson and doctoral student Leah Pyter presented the findings Nov. 15 in Washington, D.C. at the annual meeting of the Society for Neuroscience.
The study involved 53 female and 48 male Siberian hamsters.
At about 60 days of age, the hamsters began a series of tests that are used to measure anxiety and depression in the animals. Many of these tests are the same ones used by pharmaceutical companies to test anti-depressive and anti-anxiety drugs in animals before they are used in humans, Nelson said.
Tests for anxiety included one in which hamsters are placed in a large box and viewed for 60 minutes to see how much time they spend in the middle versus near the walls. Anxious hamsters will spend more time along the walls, where they feel more protected, while less anxious animals will explore the entire box.
Among the tests for depression was one in which they measured how much of a sugar drink hamsters drank over the course of several days.
Hamsters generally like this drink, but hamsters with depressive-like symptoms will not drink as much.
"We found that the amount of light hamsters were exposed to prenatally and up through weaning did have enduring effects on behavior in adulthood," Pyter said. "But these effects were tempered quite a bit by whether they spent their time as adults in long days or short days."
Research in humans also suggests people who are born during the winter are more likely to suffer from depression as adults, according to Nelson. The results in hamsters weren't clear-cut, but they did point in a similar direction, the researchers aid. "A lot more work needs to be done," Nelson added.
Also, female hamsters showed more evidence of depression than males, which corresponds to research in humans which shows more depression among women than men, Nelson said.
Pyter said future studies will examine whether drugs used to treat anxiety and depression will reduce seasonal anxiety and depressive- like symptoms in hamsters. Nelson added that they will also look at the role of seasonal changes in stress hormones and brain chemicals in depression and anxiety in hamsters.