Washington DC: New findings by medical researchers have revealed potential new treatments which could help people with cognitive diseases.
In the study, the researchers altered a gene in mice to inhibit the activity of an enzyme called phosphodiesterase-4B (PDE4B), which is present in many organs of the vertebrate body, including the brain.
In behavioural tests, the PDE4B-inhibited mice showed enhanced cognitive abilities.
They tended to learn faster, remember events longer and solve complex exercises better than ordinary mice.
However, the PDE4B-inhibited mice also showed less recall of a fearful event after several days than ordinary mice.
The findings have not been tested in humans, but PDE4B is present in humans. The diminished memory of fear among mice with inhibited PDE4B could be of interest to researchers looking for treatments for pathological fear, typified by Post-Traumatic Stress Disorder (PTSD).
The PDE4B-inhibited mice also showed less anxiety. They spent more time in open, brightly-lit spaces than ordinary mice, which preferred dark, enclosed spaces.
Ordinary mice are naturally fearful of cats, but the PDE4B-inhibited mice showed a decreased fear response to cat urine, suggesting that one effect of inhibiting PDE4B could be an increase in risk-taking behaviour.
Hence, while the PDE4B-inhibited mice excelled at solving complex exercises, their low levels of anxiety could be counterproductive for a wild mouse.
Lead author Steve Clapcote University of Leeds' said that cognitive impairments were currently poorly treated, so he was excited that their work using mice has identified phosphodiesterase-4B as a promising target for potential new treatments.
The study is published in the journal Neuropsychopharmacology.