Fluoxetine flx

All drugs were intraperitoneally (i.p.) administered in a total volume of 10.0 mL/kg (body weight). Doses are expressed as milligrams per kilogram of mouse body weight. Melatonin (MEL) (Sigma-Aldrich Corp., St. Louis, MO, USA) was dissolved in the minimum amount of absolute ethanol and then in isotonic (0.9%) saline solution. Ethanol concentration in that solution was 0.006%, so the vehicle (VEH) tested had that same amount of ethanol. Fluoxetine (FLX) and imipramine (IMI) (Sigma-Aldrich Corp., St. Louis, MO, USA) were dissolved in isotonic saline solution. Experiment series comprised independent groups of 8 animals for each specified drug treatment and behavioral test.
Single administration at ZT11 was as follows: Either MEL or its VEH were administered at ZT11 (1 h before the lights were off), and behavioral tests were assessed 7.5 h later (ZT18.5).
Single administration at ZT18 was as follows: Drugs were administered at ZT18 (the middle of the dark phase), 30 min before the behavioral tests.
Triple scheme administration (for the FST only) was as follows: First administration of the drugs was at 24.5 h before the test (ZT18; immediately after the pre-test session); the second injection was applied one hour before lights were off (ZT11; 7.5 h before the test); finally, the third administration was at ZT18, 30 min before the test [39 (link)].

MCH1 was synthesized by Medalchemy, S.L. (Spain). MCH1 was suspended in DMSO (Sigma-Aldrich, USA) and mixed with an equal volume of polyethylene glycol (PEG-600) (Sigma-Aldrich). Sterile 0.9% saline was added and the resulting suspension was stirred for 30 min at 50°C. The final composition of the vehicle solution was DMSO, PEG-600, and saline (1/1/18). Midazolam (MDZ, RichVet, BsAs, Argentina) was diluted in sterile 0.9% saline. Immediately after being dissolved, all drugs were administered through the intraperitoneal (ip) route in a volume of 10 mL/kg body weight. Fluoxetine (FLX, Sigma-Aldrich) (17 (link)) and MDZ (18 (link)) doses were selected from those reported in the literature. MCH1 doses were selected based on the ability of URB597, a well-characterized FAAH inhibitor, to increase the pharmacological effect of anandamide (19 (link)).

Mice were randomly divided into five groups: (1) control (CON, unstressed mice, n = 10 mice), (2) SPS+FS (stressed mice, n = 10 mice), (3) SPS+FS+HFE 500 mg/kg (n = 10 mice), (4) SPS+FS+HFE 1000 mg/kg (n = 10 mice), and (5) SPS+FS+fluoxetine (FLX; Sigma-Aldrich, St. Louis, MO, USA) 20 mg/kg (n = 10 mice). All drugs were dissolved in 0.9% physiological saline, and HFE and FLX were given once a day by oral gavage (intragastric administration; IG) for 14 days. Control and SPS+FS groups were administered an equal volume of 0.9% physiological saline by oral gavage (IG). To evaluate the survival of newborn cells in the dentate gyrus (DG) of the hippocampus, mice in each group were administered 6 injections of BrdU (100 mg/kg, i.p., twice daily for 3 days), a marker of proliferative cells in the S-phase, for 3 consecutive days before the experiment.