OBJECTIVETo study the effect of classic ancient prescription Kaixin San (KXS) on learning and memory abilities in chronic stress depression model rats and its possible mechanisms.

METHODRats were randomly assigned to six groups: the control group, the model group, the positive drug group (fluoxetine 10 mg x kg(-1)) and KXS groups (1000, 500, 250, 125 mg x kg(-1)). KXS were orally administrated to CMS rats for 21 days. The anti-depression activity of KXS was assessed using the sucrose consumption and the open-field test. The protecting effect for learning and memory abilities was assessed using the Morris water maze (MWM) test. Furthermore, the levels of monoamine neurotransmitters, acetylcholine (Ach) and acetyl cholinesterase (AchE) in the total brain and brain-derived neurotrophic factor (BDNF) protein in the hippocampus were determined.

RESULTThe behavior test showed that KXS significantly increased the sucrose consumption and total distance in the open-field test and notably reduce the incubation period of location and navigation in the MWM test. It could also help increase the number of times passing through the platform, the swimming distance and time in quadrant of original platform, the levels of serotonin (5-HT) and dopamine (DA) , noradrenergic (NE), Ach, BDNF protein and reduce the level of AchE in the CMS-induced rats.

CONCLUSIONKXS can ameliorate the CMS-induced depression behavior in rats and improved their learning and memory abilities, which may be related to the increase in monoamine neurotransmitters, Ach and BDNF levels.