Maternal deprivation enhances behavioral vulnerability to stress associated with miR-504 expression in nucleus accumbens of rats.
OBJECTIVE
In this study, the effect of maternal deprivation (MD) and chronic unpredictable stress (CUS) in inducing depressive behaviors and associated molecular mechanism were investigated in rats.


METHODS
Maternal deprivation was established by separating pups from their mothers for 6 hours daily from postnatal day 1 to day 14. Chronic unpredictable stress was established by water deprivation, elevated open platform, food deprivation, restraint stress and electric foot shock. The depressive behaviors were determined by use of sucrose preference test and forced swim test.


RESULTS
Rats in MD/CUS group exhibited lower sucrose preference rate, longer immobility time, and lighter body weights than rats in other groups (MD/control, non-MD/CUS and non-MD/control group). Meanwhile, higher miR-504 expression and lower dopamine receptor D1 (DRD1) and D2 (DRD2) expression were observed in the nucleus accumbens of rats in the MD/CUS group than in the other three groups. MiR-504 expression correlated negatively with DRD1 gene expression and sucrose preference rate in the sucrose preference test, but correlated positively with immobility time in forced swim test. Both DRD2 mRNA and protein expression correlated negatively with immobility time in forced swim test.


CONCLUSIONS
These results suggest that MD enhances behavioral vulnerability to stress during adulthood, which is associated with the upregulation of miR-504 and downregulation of DRD2 expression in the nucleus accumbens.
Medical Psychological Institute, Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
Yi
Y
Zhang
Xiongzhao
X
Zhu
Mei
M
Bai
Li
L
Zhang
Liang
L
Xue
Jinyao
J
Yi
D000375:Aging / Q000378:metabolism; D000818:Animals; D001522:Behavior, Animal; D002755:Choice Behavior; D003863:Depression / Q000150:complications / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D008426:Maternal Deprivation; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000235:genetics / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000235:genetics / Q000378:metabolism; D013315:Stress, Psychological / Q000150:complications / Q000235:genetics*; D013395:Sucrose
C588064:MIRN504 microRNA, rat; D035683:MicroRNAs; D012333:RNA, Messenger; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D013395:Sucrose