Behavioral differences in black Swiss mice from separate colonies: implications for modeling domains of mania.

Recent work demonstrated the advantages of using black Swiss (BS) mice to model behavioral domains of mania including reward-seeking, risk-taking, vigor, and sensitivity to psychostimulants. Until recently BS mice were only available from Taconic (TAC) farms, but a colony was recently established by Charles River (CR). The present study compared the behavioral phenotype of mice from the new CR colony to the TAC animals to evaluate if mice from CR also have the advantages as model animals for mania. TAC and CR mice were compared in a battery of tests related to domains of mania, and the effects of lithium were tested in the CR mice. CR mice showed lower activity levels and preference for sweet solution and higher immobility in the forced swim test compared with TAC mice. Furthermore, in contrast with the antimanic-like effects of lithium previously described in TAC mice, in CR mice lithium only had an antidepressant-like effect in the forced swim test. The results indicate that the CR BS mice lack the behavioral properties that make the TAC BS mice advantageous for modeling domains of mania.