The effects of glucocorticoids on depressive and anxiety-like behaviors, mineralocorticoid receptor-dependent cell proliferation regulates anxiety-like behaviors

Glucocorticoids are vital stress response hormones and facilitate stress coping. However, sustained glucocorticoid exposure is associated with negative effects on brain. The precise role of glucocorticoids in depression and anxiety remains unclear. In the present study, we found that rats exposed to chronic unpredictable stress (CUS) showed anxiety-like behavior but not depressive-like behavior in the absence of glucocorticoid production. It was interesting to find that the level of serotonin (5-HT) and the expression of tryptophan hydroxylase-2 (TPH2) were decreased after CUS in the hippocampus in sham rats, while adrenalectomy (ADX) prevented such decreases. In addition, the neurogenesis in hippocampus decreased in both sham and ADX rats after stress exposure. Furthermore, inhibition of mineralocorticoid receptor (MR) with spironolactone induced anxiety like behavior in sham rats but not ADX rats. The proliferation of cells was blocked by spironolactone. In conclusion, our results indicate that MR-dependent neurogenesis was closely related with anxiety-like behavior.