Sucrose preference test.
For SPT, a slightly modified protocol of a reported procedure (Schalla
et al., 2020) has been used. Briefly, animals had free access to 5%
sucrose diluted in tap water along with tap water twice a week, in two
different types of sessions. The first session lasted 48 hours (divided
in 2 consecutive sessions of 24h, since bottles needed to be weighted
and refilled), and was followed by a period of 24h without access to
sucrose. Following, the second session started and lasted for 2 hours.
After obtaining a basal measure the week prior to the pain induction, we
repeated the protocol every week until the end of the experiment. All
measurements were expressed as the mean ± SEM in mg of sucrose/rat
weight in kg/24h or mg/kg/2h.