HTR5A and Anxiety: Notably, the UCN triple KO mice show some basal and 24 h post-stress differences in serotonergic activities in the amygdala, subiculum and medial and later septum, which is consistent with the hypothesis that the increase in anxiety-like behavior is mediated in part by changes in serotonin and implicates a role for CRF2 receptor activation in controlling 5-HT and its potential role during the stress recovery period.