HTR1A and major depressive disorder: Studies have demonstrated that the 5HT1A receptors are involved in the pathogenesis of depression (Samuels et al., 2016) Moreover, symptoms of anxiety and depression are always accompanied by changes in the expression of 5-HT1A receptors (Xiang et al., 2017) In this study, it should be noted that regardless of age, the expression level of 5-HT1A receptors in Slit2-Tg mice tended to increase compared with that in WT mice, although these differences were not statistically significant.