Acute stress enhances anxiolytic-like drug responses of mice tested in a black and white test box

Abstract

Drug-induced facilitation of exploration of a two-compartment black and white test box was studied in mice applying different stressors before test. Tail suspension suppressed exploration of both compartments and enhanced diazepam- or eltoprazine-induced increase of exploration of the white compartment. (−)-Penbutolol reversed the effects of eltoprazine suggesting involvement of 5-HT 1A/1B receptors. Buspirone had weak effects both under standard conditions, and after tail suspension. Ritanserin suppressed exploratory behavior, and this effect was potentiated by tail suspension. In conclusion, application of acute tail suspension stress immediately before test in the black and white box enhanced the sensitivity to drugs. In contrast to this, forced swimming suppressed general behavioral activity, but in this case diazepam facilitated the behavior in both compartments. Foot shocks immediately before test reduced activity in the black compartment and did not affect the behavior in the white compartment. Thus different acute stressors modified behavior in the black and white box differently. Chronic stress (crowded housing) produced an anxiolytic-like response.