Figure 2.
Effect of intrathecal injection of serotonin receptor 1A, 2A, and 3 antagonists on the analgesic effect of [6]-shogaol against oxaliplatin-induced cold (A) and mechanical (B) allodynia. NAN-190, ketanserin, and MDL-72222 are serotonin 1A, 2A, and 3 receptor antagonists, respectively. Cold allodynia was assessed using the acetone drop test (A), and mechanical allodynia was measured using the von Frey filament test (B). All groups, except the control, received oxaliplatin injection four days prior to the behavior test. As a control for NAN-190, ketanserin, and MDL-7222220%, dimethyl sulfoxide (DMSO) was used, and 10% DMSO was used as a control for [6]-Shogaol. We administered 10% DMSO or [6]-shogaol intraperitoneally 20 min after intrathecal injection of 20% DMSO, NAN-190, ketanserin, or MDL-72222. D0: before injection of oxaliplatin. D4 (Before): before the injection of 10% and 20% DMSO, NAN-190, ketanserin, MDL-72222, and [6]-shogaol. D4 (After): 1 h after injection of 10% and 20% DMSO, NAN-190, ketanserin, MDL-72222, and [6]-shogaol. Data are presented as mean ± SD. Control: n = 6; OXA + 20% DMSO + 10% DMSO: n = 6; OXA + 20% DMSO + [6]-Shogaol: n = 6; OXA + NAN-190 + [6]-Shogaol: n = 6; OXA + Ketanserin + [6]-Shogaol: n = 6; OXA + MDL-72222 + [6]-Shogaol: n = 6. D: day; DMSO: dimethyl sulfoxide; Inject.: injection; NS: non-significant; OXA: oxaliplatin. *** p < 0.001, **** p < 0.0001 vs. Control; # p < 0.05, ## p < 0.01, #### p < 0.0001 vs. OXA + 20% DMSO + 10% DMSO with two-way ANOVA followed by Tukey’s multiple comparisons test.