Behavior of the Roman/Verh high- and low-avoidance rat lines in anxiety tests: relationship with defecation and self-grooming.

The Swiss sublines of Roman high- and low-avoidance (RHA/Verh and RLA/Verh) rats have been selected and bred for rapid (RHA/Verh) vs. extremely poor (RLA/Verh) acquisition of two-way active avoidance. Behavioral and physiological measures of emotionality, or reactivity to stress, appear to be among the most prominent characteristics differentiating both rat lines. The present study shows that RLA/Verh rats are more sensitive, as compared to their RHA/Verh counterparts, to the conflict involved in the shock-induced suppression of drinking paradigm, as well as in a hyponeophagia test. RLA/Verh rats also showed higher defecation values which were significantly correlated with the main hyponeophagia test variables. Likewise, self-grooming was more frequent in RLA/Verh rats than in their RHA/Verh counterparts and showed significant correlations with conflict-related behaviors (i.e., latency to start eating and time spent eating) from the hyponeophagia test. These results give additional support to the contention that RLA/Verh rats present higher anxiety (emotionality) than their RHA/Verh counterparts.