"Cohort removal" induces hyperthermia but fails to influence plus-maze behaviour in male mice

Mice removed last from their home cage display elevated body temperature compared with those removed first. This stress-induced hyperthermia (SIH) response has been reported for Swiss and NMRI mice and has been forwarded as a model of anticipatory anxiety. In the present study, the effects of order of removal from the home cage (cohort removal) on body temperature and behaviour in the elevated plus maze have been examined in group-housed male DBA/2 mice. Results confirm the basic phenomenon of SIH in this strain, with mice removed from the home cage in positions 4-10 displaying a significantly higher mean rectal temperature compared with those removed in positions 1-3. Despite this observation, however, detailed ethological analysis failed to reveal any significant effect of cohort removal on behaviour displayed in the elevated plus-maze paradigm. Data are discussed in relation to variations in the nature of reactions evoked in different animal models of anxiety.