Automated tests for measuring the effects of antidepressants in mice

The forced swim test (FST) and the tail suspension test (TST) are used widely for measuring the pharmacological effects of antidepressant drugs or changes in stress-evoked behavior in mice. However, inconsistent scoring techniques and poor reproducibility may result from their reliance on subjective ratings by observers to score behavioral changes. In this paper, automated versions of the mouse FST and TST were characterized and validated against observer ratings. For the FST, a commercially available video tracking system (SMART II; San Diego Instruments) measured the duration that mice swam in water-filled cylinders at a set velocity. For the TST, a commercially available automated device (Med Associates, St. Albans, VT) measured input from a strain gauge to detect movements of mice suspended from an elevated bar. Dose-dependent effects of the antidepressant desipramine on FST and TST immobility were measured in CD-1 mice using both automated devices and manual scoring from videotapes. Similar dose-response curves were obtained using both methods. However, a wide range of correlations for raters in the FST indicated that scoring criteria varied for individual raters despite similar instructions. Automated versions of the mouse FST and TST are now available and provide several advantages, including an opportunity to standardize methods across laboratories.