Figure 2. Neuropathic pain does not alter the hedonic or aversive impact of orally administered tasting substances.
Facial reactions to sweet (1% sucrose) neutral (water) and bitter (0.3 mM quinine) tastants in sham and SNL rats were scored according to the facial reactivity scale of Berridge [4]. Representative examples of “liking” and “aversive” reactions are shown on the right. (A) SNL and sham rats showed greater levels of “liking” reactions to sucrose compared to water and quinine. No difference in “liking” reactivity was detected between SNL or sham rats for each of the substances (n=11–13). (B) Neutral responses to intraoral sucrose, water, or quinine did not differ between SNL and sham rats (n=11–13). (C) Both cohorts of rats displayed the greatest amount of “aversion” reactions to quinine compared to the other substances, however, there was no difference in “aversive” reactivity between SNL or sham rats for each of the substances (n=11–13). All data are graphed as mean ± SEM.