[Effects of Central Acting Drugs on the Mirror Staircase Test]

A mirror-covered staircase was erected to study screening methods, and several basic experiments were carried out using it. The staircase consisted of 5 steps each measuring 15 cm long by 20 cm wide by 6 cm high, fabricated in a wooden device measuring 95 cm by 20 cm by 30 cm high. The inner surfaces were all mirrored, including steps, floors and walls. At the foot of the stairs, a rat weighing about 200 g was placed quietly with the back toward the stairs. The frequencies of rearing and climbing on the stairs were recorded for the subsequent 3 and 10 min. The recordings were also performed using 2 rats placed simultaneously and in a non-mirrored device of the same structure. When mirrored, the frequencies of rearing and climbing were much higher, and the average duration lasted also longer than when non-mirrored. To compare the results among the following 3 qualifications: i) a rat in the mirrored device, ii) 2 rats in the mirrored device, and iii) 2 rats in the non-mirrored device, the highest frequency of rearing for the first 3 min was observed in i). Effects of nitrazepam, phenobarbital and morphine were compared between mirrored and non-mirrored qualifications. No significant differences between them were observed in the drug-induced changes in the behaviors. Although the mirrored-staircase test as a screening method was almost identical to the non-mirrored test, it was superior in the point of continuation of augmented frequencies. As a fact arousing interest, the subject received more potent stimulation from its self image exposed on the mirrors than the image of another individual of the same species (within the same device).