FG7142 combined with restraint stress induces anxiogenic-like effects via downregulation gamma-aminobutyric acid type A receptor subunit alpha1 and 5-hydroxytryptamine 1A receptors expression in the hippocampus.

Abstract

The existing anxiety animal models are susceptible to interference, and no single animal anxiety model can predict the future anxiolytic potential and profile of new putative anxiolytics. Therefore, to find a better anxiety animal model, we used FG7142, a nonselective benzodiazepine inverse agonist. This anxiety animal model was established by intraperitoneal injection of FG7142 combined with restraint stress. Adult male C57BL/6J mice (18-20 g) were randomly classified into five groups (n = 10 per group), namely the control, restraint stress, restraint stress + 10 mg/kg FG7142, restraint stress + 20 mg/kg FG7142, restraint stress +30 mg/kg FG7142. The impact on behavior was explored by elevated plus maze, and marble burying test, followed by immunohistochemistry and quantitative real-time PCR enabled the elucidation of the possible mechanism. Compared with the control group and restraint stress group, intraperitoneal injection of FG7142 combined with restraint stress model group was found to induce anxiogenic-like behavior in elevated plus maze and marble burying test. Moreover, relative to the control group, significantly increased expression of c-fos in the hippocampus and amygdala in the model group was evident, whereas the expression of gamma-aminobutyric acid type A receptor subunit alpha1 and 5-hydroxytryptamine receptor 1A mRNA was significantly decreased in the hippocampus. These results indicated that FG7142 combined with restraint stress is sufficient to induce anxiety, and its mechanism is associated with downregulation of hippocampal gamma-aminobutyric acid type A receptor subunit alpha1 and 5-hydroxytryptamine 1A receptors.