I saw this CPA assay in a paper from Cheng et al. (2017)
This looks laborious but useful.
To measure the negative valence effect associated with brush-evoked dynamic mechanical hypersensitivity, we used a biased compartment-assignment proce- dure, in which we measured the influence of VT3Lbx1 neurons on the time of mice spending in the dark compartment receiving conditional stimulations. The CPA apparatus consisted of two chambers (10 × 10 × 15 cm per compartment), one dark (A) and one bright (B), with a metal mesh floor (i.e., the chambers, which had no floor, were placed onto a metal mesh used as the floor). The center was an inserted black (facing compartment A) and white (facing compartment B) plas- tic wall with a rectangular hole in the bottom center (4 × 8 cm; Fig. 4a). Mouse movement was recorded by a Sony camcorder. The amount of time a mouse spent in chamber A was evaluated by the experimenter after recording. On day 1, each mouse was placed in the bright compartment (B) and allowed to freely explore between chambers A and B for 15 min (pre-test). With this apparatus design, most if not all naive mice showed an initial preference for the dark chamber. Mice were conditioned over a 4-d period. On days 2 and 4, the hole in the central wall was blocked with a dark film on the A compartment side. The mouse was put in the bright chamber for 20 min. On days 3 and 5, the hole in the central wall was blocked with dark film on the B compartment side. The mouse was then placed in chamber A, and the injured hindpaw was brushed with the paintbrush from heel to toe for 20 min at ~2-s intervals. On day 6 the hole in the central wall was unblocked. The mice were tested for their compartment preference by placing them in the bright compartment first and allowing them to freely explore the entire apparatus for 15 min (post-test). The aversion score was measured as the difference in time (in s) spent in the dark compartment during pre-test versus during post-test (i.e., aver- sion score = (pre-test time in dark chamber) – (post-test time in dark chamber)).
Has anyone done this, or something like it, and have success? Any tips?
We discussed this here in the past in some capacity, and it seems like CPA might not be very easy to do with mice in pain assays: