Behavior of Wistar rats in the free-exploratory paradigm

Abstract

The free-exploratory paradigm (FEP) has been proposed as an animal model of trait anxiety and thus a model of choice to categorize heterogeneous strains of rodents, according to their anxious profile. In this context, it is important to identify and measure the behavior of these rodents on the FEP. Therefore, the aim of this study was to describe the behavioral parameters of male Wistar rats exposed to FEP. Three hundred and sixty drug-naive, adult, male Wistar rats were tested on FEP and the following parameters were evaluated: percentage of time in the novel side (%TNS), percentage of time rearing in the novel side (%RNS), percentage of distance travelled in the novel side (%DNS), attempts to enter the novel side and total distance travelled. The data obtained were expressed as median and interquartile range and as mean ± standard deviation. The preference of novelty was assessed by one sample t test. The analysis revealed that %TNS, %RNS and %DNS were significantly higher than 50%, showing a preference for novelty, as described in the literature. Furthermore, the values of the behavioral parameters %TNS obtained here will be very useful for future studies requiring to categorize animals according to their anxious trait.