Fig. 6.

LP-211 normalizes emotional pain behavior. A. Experimental design of the PEAP. The mouse can freely move between a light and dark compartment. The injured paw is stimulated in the dark compartment and the uninjured paw in the light compartment. Stimulation of the corresponding paw was repeated every 15 s. The heat maps on the right illustrate the time spent in each position 20–30 min after the beginning of the stimulation in a saline (top) and LP-211 (10 mg/kg, bottom) treated animal. In the saline treated condition, the animal spent less time in the preferred dark compartment. B. The relative time spent in the light compartment is plotted as a function of time. 20–30 min after the beginning of the stimulation of the corresponding hind paw, saline treated CCI animals showed a switch in place preference (red, n = 7). This switch was absent in LP-211 treated animals (blue, n = 8). The dashed line refers to the average of the first 10 min of the stimulation in the two conditions (37.3%). C. 10 min before the beginning of the stimulation the animals were allowed to freely explore the two compartments. The bar graph shows the relative time spent in the light compartment of saline and LP-211 treated animals. Open circles indicate individual experiments. LP-211 injection had no influence on the overall anxiety level. D. Average velocity and total distance covered of the animals during the recording period of 40 min. No differences were found for these parameters in saline and LP-211 treated animals. Error bars are S.E.M. *p < 0.05.