High concentration of glucocorticoids in the hippocampus plays opposite roles in acute and chronic phase in regulating HPA axis activity.

<p>(A) Western blotting showing CRF protein expression in the hypothalamus 2 hours after the infusion of CORT (10 µM, 2 µl) into the DG regions. n = 3 for each group. Arrow heads indicate the location of nearest band in the ladder. (B) The CORT level in the plasma 2 hours after the infusion of CORT (10 µM, 2 µl) into the DG regions. n = 4 for each group. (C) RT-PCR showing CRF mRNA in the hypothalamus 28 days after the infusion of CORT (10 µM, 2 µl) into the DG regions. n = 3 for each group. (D) The CORT level in the plasma 28 days after the infusion of CORT (10 µM, 2 µl) into the DG regions. n = 6 for each group. (E) Representative imaging of CRF-positive cells in the PVN of the hypothalamus 28 days after the infusion of CORT (10 µM, 2 µl) into the DG regions. The result was repeated in 3 mice for each group (data not shown). Immobility time in the TST (F, DMSO n = 12, CORT n = 16) and FST (G, DMSO n = 12, CORT = 16), sucrose preference (H, DMSO n = 12, CORT = 15) 28 days after the infusion of CORT (10 µM, 2 µl) into the DG regions. Error bars denote SEM, *<i>P</i><0.05, **<i>P</i><0.01, two-tailed Student's <i>t</i> test.