Figure 4.

Effect of pentoxifylline pretreatment on mechanical hypernociception induced by bradykinin, TNF-α, IL-1β and PGE₂. Hypernociception was measured before and 3 h after injection of bradykinin (Bk, 500 ng), tumor necrosis factor-α (TNF-α; 2.5 pg), interleukin-1β (IL-1β; 1 pg) or prostaglandin E₂ (PGE₂; 100 ng) into the hind paws (intraplantar, i.pl.) of rats. Vehicle (saline) or pentoxifylline (PTF; 9 mg paw⁻¹) was injected intraplantar 30 min before hypernociceptive stimulus administration. Results are expressed as means±s.e.m. of the intensity of hypernociception (Δ reaction time, s) for groups of 5–6 rats. Asterisks indicate statistically significant differences between groups and respective controls (^*P<0.01, ^**P<0.001).