Corticotropin releasing factor enhances attentional function as assessed by the five-choice serial reaction time task in rats.

Previous studies have shown that psychological stress affects attentional function, and corticotropin releasing factor (CRF) is closely related to stress responses. In the present study, we examined the effect of CRF on attentional function using a five-choice serial reaction time task (5-CSRTT) in rats. Accuracy in the 5-CSRTT was used as the index of attentional function. Human/rat CRF was intracerebroventricularly injected (0, 0.01, 0.1, or 1 microg/5 microl saline) 20 min before the beginning of the test trial in male Lister hooded rats that generally show high performance in the 5-CSRTT. As a result, 0.1 microg of CRF, but not other doses of CRF, increased accuracy in the 5-CSRTT. However, 0.1 microg of CRF did not affect impulsivity, motivation/appetite, perseverative tendency, or motor function. Even when Wistar rats, which generally show poor performance in the 5-CSRTT were used, 0.1 microg of CRF increased accuracy in the 5-CSRTT. However, the effect of CRF was not significantly attenuated by intracerebroventricular injection of the CRF(1) receptor antagonist antalarmin (5 microg). These results showed that CRF selectively enhances attentional function regardless of baseline attentional performance and rat strain, but this effect may be due to the pathways other than CRF(1) receptors. The present results suggest that CRF is involved in stress-related changes of attention and indicate that moderate stress, but not severe stress, may enhance attentional performance. Furthermore, these findings also indicate that the CRF-related substance could be a target for the development of an agent to improve attentional function.