Objective  To observe the impact on emotion in offspring rats following maternal stress during pregnancy and the possible mechanisms related with hippocampal monoamine neurotransmitters.

Method  A rat model subjected to chronic unpredictable mild stress (CUMS) during pregnancy was established to measure plasma corticosterone levels of maternal rats by radioimmunoassay. Their offspring were determined for emotional responses using sucrose preference test (SPT), open-field test (OFT), and suspend tail test (STT), and for levels of hippocampal monoamine neurotransmitters using ELISA for correlation analysis.

Result  An elevation was observed in the plasma corticosterone level of the rat model group compared with the control rats (F=12.347, P=0.001), indicating that the rat model group was under stress. The body weight of the model offspring group was lower than that of the control offspring group in PND 28 and PND 42 (P<0.05). The model offspring had lower scores of horizontal movement and vertical movement than the control offspring (P<0.05). Lower consumption of sugar water and 1% sucrose preference were found in the model offspring (P<0.05). The model offspring also presented longer rest time and less struggle counts (P<0.05) in the suspend tail test. Moreover, decreased levels of hippocampal monoamine neurotransmitters including norepinephrine, dopamine, and 5-hydroxytryptamine were found in the model offspring (P<0.05).

Conclusion  The emotion alteration in offspring is related to elevated maternal plasma corticosterone and decreased hippocampal monoamine neurotransmitters of offspring rats following maternal chronic stress during pregnancy.