Scientists who genetically modified mice to make them super-intelligent – good, we need those – discovered while about it that the smart rodents are also supremely laid-back.
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The genetically modified super-smart mice also proved to suffer less from anxiety, the scientists found.
For all that science has decoded the human genome, we don't actually know what most of our DNA does, or even what a great many of our genes do. One way to elucidate what a gene does is to change it (mutate it) and see what happens.
This team from Britain and Canada found that mutating a single gene to block the phosphodiesterase-4B (PDE4B) enzyme, which is found in many organs including the brain, made mice cleverer and at the same time less fearful.
The PDE4B enzyme is involved in cellular regulation. Other indications of the importance of this enzyme, when it's working properly at least, is that changes to it (again, mutations) have been associated with schizophrenia and bipolar affective disorder.
Hidden escapes and faces
In the experiments, published on Friday in the journal Neuropsychopharmacology, the scientists ran a series of behavioral tests on the PDE4B-inhibited mice and found they tended to learn faster, remember events longer and solve complex problems better than normal mice.
The "brainy" mice were better at recognizing a mouse they had seen the previous day, the researchers said, and were also quicker at learning the location of a hidden escape platform.
They were also less able to recall a fearful event after several days than ordinary mice, and as PDE4B is also found in humans, this could be of interest in the search for treatments for brain conditions as well as mental decline linked to ageing.
The experiments also showed that PDE4B-inhibited mice suffered less anxiety, choosing to spend more time in open, brightly lit spaces than normal mice, which preferred dark, enclosed spaces.
And while mice are naturally scared of cats, the modified mice responded less fearfully to cat urine, suggesting that inhibiting PDE4B could increase risk-taking behavior.
Now the team is working on developing drugs that can specifically inhibit PDE4B (which means, stop it from working). As usual, the drugs will first be tested first in animal models – meaning, tested on animals before being tried on humans.
"Our work using mice has identified phosphodiesterase-4B as a promising target for potential new treatments," stated Steve Clapcote, a lecturer in pharmacology at Britain's Leeds University, who led the study.
It's extremely early days to associate the discovery of the super-smart, laid-back mice with benefits to humanity, but the team postulates that further elucidation of the PDE4B enzyme could help treat neuro-degenerative conditions such as Alzheimer's, schizophrenia – and, given the anxiety association, even post-traumatic stress disorder. That could even apply to animals: they suffer from PTSD too.