Fig. 4.

A) Effect of D4 on nociception as measured by the hotplate assay at 52°C. Panels on the left show paired individual test measurements after 20 min and 80 min vehicle or D4 injection. There was no statistical difference (P = 0.83, paired t test, 7 degree freedom) between vehicle and D4 at 20 min after injection. At 80 min after D4 injection, the difference in withdrawal latency became statistically significant (P = 0.04, paired t test, 7 degree freedom). Panels on the right show means and SEM (n = 8). Unpaired t tests were also used to compare consolidated data, yielding P = 0.91 at 20 min and P = 0.14 at 80 min (14 degrees of freedom). ns = not statistically significant; * = statistically significant. B) Effect of D4 (active compound) and D4.14 (inactive compound) on nociception as measured by the hotplate assay at 55°C. Panels on the left show paired individual test measurements after 80 min vehicle, D4, and D4.14 injections. At 80 min after D4 injection, the difference in response latency was highly statistically significant (P = 0.009, paired t test, 7 degree freedom), while D4.14 did not have an effect on pain perception (P = 0.78, paired t test, 7 degree freedom). Panels on the right show means and SEM (n = 8). Unpaired t tests were also used to compare consolidated data, yielding P = 0.007 for D4 and P = 0.8 at 80 min for D4.14 (14 degrees of freedom). ns = not statistically significant; ** = highly statistically significant.