In the tail flick model, the subject’s tail is dipped in water (55°C) until it retracts its tail (maximum duration of exposure is 15 sec to prevent any risks of tissue damage). The latency to retract is recorded.
Hot Plate Test
In the hot-plate test, the animal will jump off the plate or lick its paw when the heat becomes uncomfortable. The temperatures at which we use the hotplate (49-56C) combined with the limited amount of time on the hot plate (no more than 4 minutes up to 52C or 60 seconds up to 56C) ensures that no tissue damage will occur and the animal will not be burned, while giving an accurate assessment of sensitivity threshold.
Von Frey Test
In the Von Frey model, a series of thin nylon filaments of increasing diameter (Von Frey Hairs) is applies to the bottom of the feet with sufficient force to bend the hair into a U shape to see which thickness of filament is annoying enough to cause the animal to retract its foot.