Figure 1.
CBS inhibitor attenuates mechanical hyperalgesia in CFA rats. Escape threshold (ET) was determined by measuring mechanical threshold in response to von Frey filaments. (A) Injection of CFA into TMJ area of rats (n = 9) significantly decreased ET (filled bars) while injection of the same volume of normal saline (NS, n = 9) did not alter ET (open bars) significantly. The lowered ET started 8 hours after CFA injection and lasted for ~6 days (n = 9, *p < 0.05, compared with that before CFA injection (PRE), Dunn’s post hoc test following Friedman ANOVA). (B) Subcutaneous injection of AOAA 8 hours after CFA injection had a significant effect on the ET in CFA rats, in a dose- and time-dependent manner. ET was increased 30 minutes after administration of AOAA in CFA rats in a dose dependent manner (n = 13 rats for each group, *p < 0.05 compared with NS, Kruskal-Wallis ANOVA followed by Tukey post hoc test). (C) Subcutaneous injection of AOAA at 9 mg/kg body weight or same volume of NS had no significant effects on ET in healthy control rats (n = 13 rats for each group). (D) Subcutaneous injection of L-Cysteine (L-Cys), an endogenous substrate for CBS to generate H2S, produced mechanical hyperalgesia in healthy control rats, in a dose- and time-dependent manner (n = 6 rats for each group, *p < 0.05 compared with NS, Kruskal-Wallis ANOVA followed by Tukey post hoc test).