Pain-related behaviour in the different treatment groups. (a) Thresholds indicating primary mechanical hyperalgesia are significantly reduced in saline i.a.-treated animals in the acute phase of arthritis, i.a.-sgp130-treated animals show a significantly faster recovery with increased thresholds on Days 3 and 7 after induction of arthritis. (b) i.p.-sgp130-treated animals show a faster increase of thresholds as compared to i.p.-saline-treated animals in the chronic phase of AIA (Days 14 and 21). (c) Overall antinociceptive effects as calculated from areas under the curve. Data are presented as mean ± SEM. *P < 0.05; **P < 0.01; n = 9 for all groups. Controls in (A) and (B) show values from immunized rats without AIA induction.