Tuesday, August 24, 1999 Published at 09:40 GMT 10:40 UK
'Scared mouse' joins medical models
Mice can provide models of human diseases
The new mouse is more afraid of raised, open walkways than normal mice, but its worries can be treated with doses of Valium-type drugs. It is the first mouse to have a defined genetic mutation related to the biological mechanisms which cause anxiety disorders in humans.
The disorders are partly determined by life experience, but genes are likely to play a role too. For example, it is more likely for identical twins (who have identical genes) both to suffer PTSD after war combat than non-identical twins.
The mouse was developed by a team at the Swiss Federal Institute of Technology and the University of Zurich and reported in the journal Nature Neuroscience.
Commenting on the research, Stephan Anagnostaras, a neurobiologist at the University of California, Los Angeles, said: "The mutant mice may represent a good genetic model because they are likely to overreact to many anxiety-provoking situations."
Professor Anagnostaras said there were three areas where the mice could be useful:
The anxious mice were bred to have a mutation in the gene which controls the brain receptor for GABA, an important neurotransmitter.
In another test, the anxious mice spent about 40% less time in the more brightly-lit areas of a maze, preferring to hide in the dark. Again, treatment with diazepam removed the differences.
The fact that the diazepam has the same effect as it does in humans suggests that the underlying mechanism is similar. This mechanism is still not completely understood but the nervous mice's twitchy behaviour will certainly help to reveal it further.