Fig. 2

d-Serine exhibits antidepressant-like effects in FST, TST, and CSDS models. C57BL/6J mice were injected into bilateral NAc with a single dose of vehicle (Control), fluoxetine (5 µg/perside), or d-serine (2, 5 µg/perside). The behavioral tests were conducted 30 min after the injection. Meanwhile, CSDS-stressed mice received daily injections (injected into bilateral NAc) of vehicle (Control), fluoxetine (5 µg/perside), or d-serine (2, 5 µg/perside) for 14 days, behavioral tests were then conducted. The vehicle referred to 0.9% saline (injected into bilateral NAc). A d-Serine observably reduced the immobility time of C57BL/6 J mice in FST. B d-Serine observably reduced the immobility time of C57BL/6J mice in TST. C d-Serine administration had no effects on spontaneous locomotor activity of mice in the open-field test. In C, "1" represents peripheral activity, "2" represents central activity, and "3" represents total activity. D The antidepressant-like outcomes of d-serine in the social interaction test. CSDS + d-serine mice spent significantly more time concerned with social interaction than CSDS + vehicle mice. E The antidepressant-like outcomes of d-serine in the sucrose preference test. CSDS + d-serine mice showed significantly higher sucrose preference than CSDS + vehicle mice. Fluoxetine was used as a positive control. The data are expressed as mean ± SEM (n = 12); *P < 0.05, **P < 0.01, significantly different from control + vehicle; ^##P < 0.01 vs CSDS + vehicle. Comparisons were made by one-way ANOVA followed by a post-hoc LSD test