Figure 5.
Effect of intrathecal administration of serotonin receptor 1A and 3 agonists on oxaliplatin-induced cold (A) and mechanical (B) allodynia. (±)-8-hydroxy-2-(di-n-propylamino) tetralin hydrobromide (8-OH-DPAT) and 1-(m-chlorophenyl)-biguanide (m-CPBG) are serotonin 1A and 3 receptor agonists, respectively. 8-OH-DPAT (10 μg/mouse, concentration 1 μg/μL) and m-CPBG (15 μg/mouse, concentration 1.5 μg/μL) were injected intrathecally. Cold allodynia was assessed using the acetone drop test (A) and mechanical allodynia was measured using the von Frey filament test (B). Phosphate-buffered saline (PBS) was used as a control for both 8-OH-DPAT and m-CPBG. D0: before injection of oxaliplatin. D4 (Before): four days after injection of oxaliplatin. D4 (After): 30 min after injection of 5-HT receptor agonists. Data are presented as mean ± SD. D: day; DMSO: dimethyl sulfoxide; Inject.: injection; NS: non-significant; OXA: oxaliplatin; PBS: phosphate-buffered saline; OXA + PBS: n = 5; OXA + [6]-Shogaol: n = 6; OXA + 8-OH-DPAT: n = 5; OXA + m-CPBG: n = 6. * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001 vs. OXA + PBS with two-way ANOVA followed by Tukey’s multiple comparisons test.