Short CommunicationChronic stress effects on working memory: Association with prefrontal cortical tyrosine hydroxylase

- Chronic stress affects working memory function in rats.
- Altered working memory is associated with prefrontal cortical tyrosine hydroxylase.
- Chronic stress effects on working memory depend on prefrontal tyrosine hydroxylase.

Chronic stress causes deficits in cognitive function including working memory, for which transmission of such catecholamines as dopamine and noradrenaline transmission in the prefrontal cortex (PFC) are crucial. Since catecholamine synthesis depends on the rate-limiting enzyme, tyrosine hydroxylase (TH), TH is thought to play an important role in PFC function. In this study, we found that two distinct population existed in Sprague-Dawley rats in terms of working memory capacity, one with higher working memory capacity, and the other with low capacity. This distinction of working memory capacity became apparent after rats were exposed to chronic stress. In addition, such working memory capacity and alterations of working memory function by chronic stress were associated with TH expression in the PFC.