One-way avoidance learning and diazepam in female roman high-avoidance and low-avoidance rats

The goal of this experiment was to study the influence of the time spent in the safe compartment (30 vs. 1 s) and of an intraperitoneal injection of diazepam (1 mg/kg vs. vehicle) on one-way avoidance learning, in inbred female roman high-avoidance and roman low-avoidance rats. Rats learned to run from a danger compartment, where they received a warning signal (88 dB tone) followed by a 1 mA electric footshock, to a safe compartment, where these stimuli were not presented. The number of trials needed to reach 10 consecutive avoidance responses was the dependent variable. Roman low-avoidance rats exposed to 1 s in the safe compartment showed poorer performance than their roman high-avoidance counterparts. These differences were not observed in rats exposed to 30 s in the safe place, and were abolished by the injection of diazepam. These results suggest the importance of fear and reinforcement in one-way avoidance learning and its usefulness for studying emotional processes underlying genetic or pharmacological manipulations. © 2007 Lippincott Williams & Wilkins, Inc.