Fig. 6.
Blockade effects of a single intrathecal injection of the specific glucagon-like peptide-1 receptors (GLP-1Rs) antagonist exendin(9–39) (A–D) and multiple daily injections of GLP-1R gene silencer small interfering RNA (siRNA)/GLP-1R (5 g/day) for 7 days (E–F) on the antihyperalgesic and antiallodynic effects of Lamiophlomis rotata (L. rotata) aqueous extract, shanzhiside methylester (SM), and 8-O-acetyl-SM in the mouse and rat formalin test and rat neuropathic pain test. (B) Dose–response analysis of the blockade effect of exendin(9–39) on antihyperalgesia produced by gavage with L. rotata in mice, best fitted by the nonlinear least-squares method. (F) Inhibitory effect of siRNA/GLP-1R on gavage L. rotata-induced antihyperalgesia of formalin-induced tonic flinching response measured by the area under the curve between 10 and 90 min (AUC10–90 min). (G) Inhibitory effect of intrathecal siRNA/GLP-1R for 7 days on GLP-1R protein expression in the spinal cord homogenates. The inset shows representative gels. The data are presented as means ± SEM (n = 6 in each group). *, #Statistical significance compared with the vehicle control group and L. rotata aqueous extract group, SM group, or 8-O-acetyl-SM group (P < 0.05 by one-way ANOVA followed by post hoc Student–Newman–Keuls test), respectively.