Transporting rats to the test situation on a cart can modify rat exploratory behavior in the elevated plus-maze

Male Wistar rats were submitted to a 24-h period of social isolation combined with a 24-h period of exposure to a different vivarium, of transportation to the test room either by cart or gently carried by hand, and immediate testing in an arena and in the elevated plus-maze. Results showed that transportation by cart was aversive inasmuch as it decreased exploratory behavior in the maze. They also suggested that exploratory behavior in the closed arms of the plus-maze was also modified by aversion. This trend was reversed when the rats were also socially isolated before testing. The data suggest that less intense anxiety, as caused by social isolation or dart transportation alone, trigger mechanisms that mediate less energetic behavior, while higher levels of anxiety (as produced by the two combined) trigger mechanisms that mediate more vigorous activity. These results are comparable to others from studies showing that rats switch from active to static to explosive behaviors with increasing intensities of aversion.