Tail-flick testing

Tail-flick nociception was measured using a Columbus Instruments TF-1 analgesia meter (Columbus, OH) as previously described by our group (Morgan et al., 2014; Marcus et al., 2015; Nealon et al., 2019; Henderson-Redmond et al., 2020). Prior to testing, mice were acclimated to placement in a Broome-style restraint and placed on the apparatus. The tail-flick was calibrated to an intensity of 5 to elicit a baseline tail withdrawal latency of approximately 3–4 s in untreated wild-type mice. Nociception was measured as the latency (seconds) to elicit a withdrawal response (tail-flick) from the heat stimulus. To avoid tail tissue damage, a cut off time of 10 s was used. As with the hot plate test, results were reported in %MPE.