2.11. Carrageenan-Induced Thermal Hyperalgesia

This method was performed, as described by Sammons et al. [25]. Two measures (with 30 min intervals) prior to carrageenan injection were done and the average result was referred to as “baseline”. Animals (n = 8 per group) received an intraplantar injection of carrageenan (25 µL/paw, 2%) and after 1 h were placed in a hot plate (Insight Equipment, São Paulo, Brazil) set at 55 ± 1 °C. The reaction to the hot plate was recorded as mentioned previously. Vehicle, C_20:0-5HT, or C_22:0-5HT was orally administered to mice 30 min before the injection of carrageenan. Reductions in the reaction time on the hot plate were taken as indicative of the development of inflammatory hyperalgesia.