Differential effects of acute and chronic treatment with the flavonoid chrysin on anxiety-like behavior and Fos immunoreactivity in the lateral septal nucleus in rats

Sa？etak The aim of this study was to compare the effects of acute (a single injection) and chronic (21 consecutive days) treatments with chrysin 2, 4, and 8 umol kg–1 on anxiety-like behavior and Fos immunoreactivity in the lateral septum nucleus (LSN), a structure that is involved in the regulation of anxiety, in male Wistar rats. These effects were compared with the clinically effective anxiolytic diazepam 7 umol kg–1. The results showed that acute, but not chronic treatment, with 4 umol kg-1 chrysin exerted anxiolytic- and antidepressant-like effects, andwith these effects were being similar to that of diazepam. Also, none of the above above-mentioned treatments did alter Fos immunoreactivity in the LSN, but a tendency towards athe reduction of this variable was detected with chrysin 4 umol kg–1 and diazepam 7 umol kg–1. Altogether, results suggest that chrysin exerts anxiolytic-like effects, but however, it can produce pharmacological tolerance after repeated use, similar to benzodiazepines