The role of cortical serotonin in anxiety and locomotor activity in wistar rats (Extra Credit)

Huston, J.P., Muller, C.P., & Pum, M.E. (2009). The role of cortical serotonin in anxiety and

Locomotor activity in wistar rats. Behavioral Neuroscience, 123(2), 449-454. doi: 10.

1037/a0014478

Retrieved from PsychArticles

Serotonin plays an important role in producing anxiety in the brain. This study focuses on three brain regions and the role serotonin plays in inducing anxiety in them. Male rats were used as subjects. Each were given a bilateral lesion on the serotonin area of the medial prefrontal cortex (mPFC), the entorhinal cortex (EC) and the occipital cortex (OccC). The procedure was done under sedation and meds for post operative pain were given. After a seven day recovery period the rats were tested in a maze. Two weeks following the tests the rats were euthanized and their brains removed to be examined for dopamine and serotonin levels in the three brain regions. Anxiety like behavior in the mPFC increased due to a lack of serotonin. The rats were lethargic and did not go as far in the maze and spent more time in the center of it. The lack of serotonin had no effect on the EC or OccC. When stress was induced the serotonin levels increased in the mPFC. The levels of serotonin appear to be regulated by the raphe nuclei in the mPFC. Dopamine levels increased in the nucleus accumbens and exhibited a compensatory response. The conclusion is that serotonin induced anxiety is confined to certain subcortical areas and does not go all over the brain.