BEHAVIORAL PROFILES OF 2 WISTAR RAT LINES SELECTIVELY BRED FOR HIGH OR LOW ANXIETY-RELATED BEHAVIOR

Over the past years, two breeding lines, derived originally from outbr ed Wistar rats, have been established that differ markedly and consist ently in their anxiety-related behaviour in the elevated plus-maze. At the age of ten weeks, rats were rested once on the elevated plus-maze and the males and females displaying the most anxious and the least a nxious behaviour were sib-mated to start a new generation of the high anxiety-related behaviour (HAB) and the low anxiety-related behaviour (LAB) lines, respectively. The resulting difference in emotionality be tween these two lines was also evident in an open field test and corre lated with differences in the forced swim test. In the open field, the HAB rats tended to be less active and explored the central zone of th e open field much less than the LAB animals. In the forced swim test, HAB rats started floating earlier, spent significantly more time in th is immobile posture and struggled less than LAB rats. However, in an o lfactory-cued social discrimination task there was no difference betwe en male and female animals from either line. The overall performance i n these various behavioural tests suggests that selective breeding has resulted in rat lines not only differing markedly in their innate anx iety-related behaviour in the plus-maze, but also in other stress-rela ted behavioural performances, suggesting a close link between the emot ional evaluation of a novel and stressful situation and an individual' s coping strategy. (C) 1998 Elsevier Science B.V. All rights reserved.