3.2 Antidepressant-like effects of D-serine in the FST and TST
of mice
FST and TST in mice are widely
used for detecting potential antidepressant-like activity(Wang et al.,
2020). D-serine was injected into the bilateral NAc, with fluoxetine
used as the positive control. Analysis indicated that
compared with the vehicle group,
D-serine (2, 5 ug/perside) or fluoxetine treatment significantly
decreased the immobility time in the FST (Figure 2A). Similar to the
consequences of FST, D-serine administration robustly reduced the
duration of immobility of mice in the TST, compared with the vehicle
group (Figure 2B). The magnitude of the D-serine (5 ug/perside) induced
anti-immobility effect was comparable with that of fluoxetine (5
ug/perside).
To exclude the probability that the reduced immobility in these tests
might be as a result of an increase in
spontaneous locomotor
activity(Eissa et al., 2020), mice were exposed to the open-field test.
We found no important differences in the number of squares an animal
crossed between the center region or the periphery region in all the
groups (Figure 2C), and no effects for drug administration. These data
indicated that the decrease of immobility observed in the two tests
after D-serine disposal was not because of locomotor hyperactivity.
Together, the data from the three tests revealed that D-serine may have
antidepressant-like effects in control mice.