4.5.1. Measurement of Thermal Hyperalgesia

For the assessment of heat hyperalgesia, a Lsi LETI-CA hot-plate (LE 7406, Italy) was used. The mice were put in a transparent cylinder (diameter = 20 cm and height = 25 cm). Following a 30-min adaption period, each mouse was exposed to radiated heat from the hot-plate that directly affects the hind paw plantar medial surface. To prevent tissue damage, a cut-off time was adjusted at 45 s [48,49]. The hot-plate temperature was set at 55 °C. The latency to licking was determined in terms of the time calculated from positioning the animal on the hot-plate surface until it started paw licking, whereas the latency to jumping was defined as the time to successfully jump off the glass cylinder.