The expression of CREB in hippocampus of chronic stress depression rat and the interference of fluoxetine

Abstract

Objective To research the expression of CREB in hippocampus of chronic stress depression rat and the interference of fluoxetine to the CREB. Methods All the experimental rats were divided by random into 3 groups:depression group, fluoxetine group and control group. The rats of depression group and fluoxetine group were applied stress for 21 days, and meanwhile the rats of control group were fed normally. The rats of fluoxetine group were applied fluoxetine by peritoneal injection(10mg/kg), and the rats of another groups were given normal sodium of the same volume by peritoneal injection. The ethology examination was performed by using method of open-field and experiment of fluid consumption. The expression of CREB was detected by immunohistochemical method and Western-blotting. Results After the chronic stress, the horizontal crossing numbers, the erection times, the modification times and the percentage of sacchar-consumption of the rats of depression group were 8. 2 ±2. 7;8. 1 4-3. 5;4. 3 4-1. 6 and 52. 5%4-7. 8%respectively, which were less than control group(31. 3 4-5. 8;13. 9 ±3. 2;10. 6 ±2. 4 and 68. 3%±4. 5%;P＜0. 01). The horizontal crossing numbers(15. 3 ±7. 7)and themodification times(6. 2±1. 5)of fluoxetine group were less than those of control group(P＜0. 01), but more than depression group(P＜0. 05);the erection times(8. 2 ±5. 6), fluoxetine group was less than control group(P＜0. 01), but no obvious difference with depression group(P＞0. 05);the percentage of sacchar-consumption (66. 7%±5. 1%), fluoxetine group was more than depression group(P＜0. 05), but no significant difference compared with control group(P＞0. 05). In both immunohistochemical method and western-blotting, the level of CREB in the hippocampus of depression group was less than that of Control group(P＜0. 01), and the level of CREB in the hippocampus of fluoxetine group was less than that of Control group(P＜0. 01)but more than that of depression group(P＜0. 01). Conclusion The expression of CREB in hippocampus of chronic stress depression rat decreased and can be reversed by fluoxetine to some extent. Key words: cAMP response element binding protein(CREB); Chronic stress; Fluoxetine