Mice were treated with either LM 4131 (10 mg/kg) or WIN-55,212-2 (10 mg/kg), or corresponding vehicle by IP injection. Every 15 minutes, the rectal temperature of the mice was taken using a lubricated rectal thermometer for a total of 1 hour post drug injection. To test catalepsy every 15 minutes the hindpaws of the mice were rested on a table and the front paws of the mouse were placed on a metal ring attached to a stand elevated 16 cm above the table. The time for the mouse to place its front paws on the table was recorded. For the hot plate antinociception test, mice were placed on a flat surface that was electrically-heated to 55°C within an open Plexiglas tube, which was cleaned in between testing each mouse with Vimoba, a chlorine dioxide solution. The latency of the mice to respond upon placement on the hot plate apparatus by shaking, hindpaw licking, jumping, or tucking of the forepaws or hindpaws was recorded.