6533b85efe1ef96bd12c065d

RESEARCH PRODUCT

The GABAergic effect of low doses of lorazepam on social behavior

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The aim of this work was to test the antiaggressive effects of lorazepam and to determine whether these effects were mediated by benzodiazepine receptors. In a first experiment, male mice were injected with lorazepam in a range of low doses (0.05, 0.1, 0.2, and 0.6 mg/kg) or saline solution. In a second experiment, 1 mg/kg of Ro 15-1788, a benzodiazepine receptor antagonist, and a saline solution were injected before the behavioral test. Results showed that 0.6 mg/kg of lorazepam was the only dose that decreased the total duration of threat ( P < .01) and social investigation ( P < .05) and that 1 mg/kg of Ro 15-1788 had no effects. In the third experiment, animals received two injec- tions: 0.6 mg/kg of lorazepam plus 1 mg/kg of Ro 15-1788, 0.6 mg/kg of lorazepam plus saline solution, or saline solution plus saline solution. Those treated with lorazepam and saline solution spent less time digging (P < .001), threatening (P < .001), and attacking (P < .05) and more time avoiding the opponent (P < .01) or being immobile (P < .001) than the controls. Ro 15-1788 was successful in completely antagonizing the behavior modulated by lorazepam. Aggr. Behav. 28:248- 256, 2002. © 2002 Wiley-Liss, Inc.