We have previously described a depressive phenotype in male mice stemming from three weeks’ single housing, demonstrated as an exacerbated transient hypothermia following a challenge with the serotonin (5-HT) receptor agonist 8-OH-DPAT. In an attempt to flesh out the phenotype, we carried out a battery of tests used to assess depressive states on C57BL/6 mice of both sexes. When combining the 8-OH-DPAT challenge with the tail-suspension test, an open field
test, a sucrose preference test, and blood samplings for measuring serum levels of oxytocin, we could find no clear evidence of depressive states in the single housed animals. The fact thatwe could not replicate our previous findings is puzzling; however, we suspect that the stressful nature of the test battery may have been detrimental to the model. These negative findings and their implications may prove of significant importance moving forward with studying natural models of depression.