Alpha-synuclein transgenic mice exhibit reduced anxiety-like behaviour.

Up to 40% of Parkinson's disease patients suffer from anxiety, but little is known about the mechanisms involved. We used the elevated plus maze and open field test to evaluate groups of young adult mice expressing different levels of alpha-synuclein, including mice transgenic for human alpha-synuclein with the A53T mutation. Compared to alpha-synuclein knock-out mice and wild-type controls, alpha-synuclein A53T transgenic mice exhibited reduced anxiety-like behaviour by spending markedly greater amounts of time on the maze open arms and by a higher proportion of entries to the open arms. In the open field, transgenic mice showed a trend towards reduced locomotor habituation and increased thigmotaxis. These results indicate a possible role for alpha-synuclein in anxiety-like behaviours.