Figure 1.

Supraspinal antinociception produced by morphine, methadone, and nalbuphine in the hot plate test in Gα_o transgenic mice. Antinociception was measured in wild-type and Gα_o +/− mice 30 min following morphine in the (a) 52 °C or (b) 55 °C hot plate test, (c) 30 min following methadone in the 52 °C hot plate test, and (d) 15 min following nalbuphine in the 52 °C hot plate test. Data represent the mean±SEM for morphine at 52 °C (n=7) and 55 °C (n=9–10), for methadone (n=7–15), and for nalbuphine (n=8–10). Legend in panel (a) also describes panels (b) through (d). Asterisks indicate a statistical difference vs wild type by Bonferroni's post-test (^*p<0.05, ^**p<0.01, ^***p<0.001).