Selective dopamine depletion within the medial prefrontal cortex induces anxiogenic-like effects in rats placed on the elevated plus maze.

The objective of this study was to investigate if selective dopamine depletion within the medial prefrontal cortex modifies the anxiety state in rats. Anxiety was evaluated by using the elevated plus maze test, an anxiety model. Dopamine depletion in the medial prefrontal cortex (79% vs. controls) induced a significantly lower preference to stay on open arms together with a reliably lower frequency of open arm entries, as well as a significant increase of percent time spent on closed arms. Although locomotion was also significantly reduced, protected head-dipping and protected stretched attend, novel "ethologically derived" indices of anxiety, were reliably enhanced. Taken together, the results are indicative of enhanced anxiety level despite hypomotility. The findings confirm that prefrontocortical dopamine activation is necessary for coping with an anxiogenic challenge, allowing the animal to display adaptive exploratory responses in a fear-inducing environment.