[ effect of dexamethasone on anxiety related behavior in mice]

ABSTRACT

Previous studies have suggested that activation of the glucocorticoid receptors may have a modulatory effect on fear and anxiety. Therefore, the aim of this study was to determine the role of glucocorticoid hormones on modulation of anxiety in elevated plus-maze model in mice. In this experimental study, 60 male mice [25-30 g] were included. They were randomely divided into test and control groups. The test group received different doses of dexamethasone, as an agonist of glucocorticoid receptors, at 0.1, 0.3, 1, 2 and 10 mg/kg, Subcutaneausly, and the control group received the same volume of 2% ethanol in normal saline 30 minutes before the evaluation of their behavior. Twenty five minutes after the injection, the mice were put in a black box for 5 minutes to induce their activity and stress. The animals were then individually transferred to a standard elevated pluse-maze in regulated time and the percentage of time spent in the open arms and the ratio of open arm entries to total entries in 5 mins was measured. Results indicated that dexamethasone with the doses 0.3 and 1mg/kg, significantly reduced anxiety in mice [p<0.01]. However, this effect was not observed at 0.1 and 2mg/kg. Our findings also showed that denamechasone at the dose of 10 mg/kg increased anxiety behavior in mice [p<0.01]. The findings of this study indicated that glucocorticoids have important role in modulation of anxiety related behavior in a dose dependent manner using an elevated plus maze model in mice