Fig. 1.

Experimental design and schedule of the treatment regimen, behavioral and neurochemical analyses. a Mice were treated with a single administration of ketamine (1 or 5 mg/kg, i.p.) or guanosine (1 or 5 mg/kg, p.o.) 1 week prior to the administration with vehicle or corticosterone. b Mice were daily administered with fluoxetine (10 mg/kg, p.o.) for 3 weeks before starting the chronic administration with vehicle or corticosterone. c Mice were treated with a single administration of a subthreshold dose of ketamine (1 mg/kg, i.p.) plus a high dose of guanosine (5 mg/kg, p.o.) 1 week before the administration with vehicle or corticosterone. a, b, c Vehicle or corticosterone (20 mg/kg) was administered orally (p.o.), once a day, for 21 consecutive days. On the 22nd day, 24 h after the last corticosterone administration, animals were subjected to the depression-related behavioral tests, namely tail suspension test, open-field test, and splash test (10 min apart). Subsequently, mice were immediately euthanized by decapitation and the hippocampus and prefrontal cortex were collected for western blotting analysis. Figure designed using images from Mind the Graph.