EFFECTS OF DIFFERENT HANDLING-STIMULATION PROCEDURES AND BENZODIAZEPINES ON 2-WAY ACTIVE-AVOIDANCE ACQUISITION IN RATS

The acquisition of two-way active (shuttle{ballot box}) avoidance involves a conflict situation which can be used as an animal model of anxiety, since it is sensitive to manipulations of the animal's emotivity/reactivity. The results from the present study (experiment 1) add relevant support to that proposal, since diazepam (2 and 4 mg/kg) and the triazolobenzodiazepine alprazolam (1, 1.25 and 1.5mg/kg) significantly improved avoidance performance in shuttle{ballot box} acquisition in rats in agreement with previous data. In another study (experiment 2), a mild stressful (10-day) handling procedure (i.e. handling which tends to increase the emotional reactivity of the animals, as showed in experiment 3) was found to affect such behaviour in an opposite direction to that of the two benzodiazepines. Conversely, when an habituating handling procedure (i.e. handling which leads to less reactive animals; experiment 3) was used, the acquisition of shuttle{ballot box} avoidance was improved (experiment 4). The results are discussed in relation with previous data showing that the particular parameters used in the exposure to stressful stimuli may lead to either sensitization or habituation of anxious responses. © 1991 The Italian Pharmacological Society.