Effect of predatory stress on sucrose intake and behavior on the plus-mazein male mice

In this study, the effect of the exposure of male mice to sensory stimuli f rom rats was assessed on both sucrose intake and the elevated plus-maze tes ts. CDI male mice were trained in the sucrose intake task (the prestress ph ase) and, subsequently, distributed into two groups. The stressed group was accommodated in the same room as rats and the control group with mice (the stress phase). After being transferred, animals were tested on sucrose int ake and the plus-maze (acute tests) and retested three times a week for suc rose intake and once on plus-maze on the last day (chronic tests). After ac ute exposure to the predator, the only difference between stressed and cont rol animals was a higher number of fecal boli left on the plus-maze by the former. During the chronic phase, stressed animals showed a lower level of sucrose intake and higher level of anxiety than controls. In conclusion, th is study shows that chronic exposure of male mice to stimuli from rats redu ces the sensitivity to the rewarding properties of sucrose and prevents the habituation to the plus-maze observed in controls. Thus, this study sugges ts that exposure of mice to sensory stimuli from rats may provide an animal model of stress, and that these species should not be routinely housed tog ether. (C) 1999 Elsevier Science Inc.