Formalin-induced nocifensive behavior is attenuated in males DRD5KO mice. A, B, Formalin-induced flinching and licking behavior is reduced in DRD5KO male mice. C, D, The second phase of the formalin test is significantly blunted in male DRD5KO compared with their WT littermates. N = 6 mice per group. E, F, DRD5KO does not affect formalin-induced flinching or licking behavior in female mice. G, H, No significant differences were observed in the formalin test phases in female WT and DRD5KO mice. N = 6 mice per group. *p < 0.05 (two-way ANOVA with Bonferroni post hoc test).