Two inbred rat strains contrasting for anxiety-related behaviors show similar levels of defensive responses to cat odor.

Rodents are known to display fear-related responses when exposed to the odor of natural predators, such as cats, even when they are totally naïve to these stimuli. Based on that, a behavioral test in which rats are exposed to cat odor has been developed and proposed to model some forms of anxiety. The objective of the present study was thus to compare the LEW (Lewis) and SHR (spontaneously hypertensive rats) inbred rat strains, which display genetic differences in other classical models of anxiety, in the cat odor test. As expected, cat odor produced an increase in fear-related behaviors. However, no clear differences were found between the two strains tested. These results suggest that the type of stress experienced by LEW and SHR strains exposed to cat odor is different from that elicited by exposure to classical models of anxiety such as the elevated plus-maze, black/white box and open-field tests.