Fig. 2.

Effect of H₂S donor and TRP channel antagonists on 0.5% formalin-induced nociceptive behavior in diabetic rats. a, b NaHS-induced hyperalgesia (a donor of H₂S; 3–100 μg/paw, s.c.) in diabetic rats subjected to the formalin test. Antinociceptive effect observed after subcutaneous administration of vehicle (Veh) or increasing doses of c, d HC-030031 (TRPA1 antagonist; 100–1000 μg/paw), e, f SKF-96365 (TRPC antagonist; 10–100 µg/paw) or g, h capsazepine (TRPV1 antagonist; 0.3–30 μg/paw, s.c.) during the second phase of the 0.5% formalin test in diabetic rats. Data are expressed as mean ± SEM of 6 animals. *Significantly different with respect to the vehicle (Veh), determined by one-way ANOVA followed by Dunnett’s test with a P < 0.05. CL contralateral