ABSTRACT
Objective To investigate the correlation between cognitive development and levels of dopamine(DA) and 3,4-dihydroxyphenylacetic acid(DOPAC)in the hippocampus of 80-day-old neonatal rats born of fear-impaired pregnant rats. Methods The pregnant rat model of fear-impaired kidney was established by watching other rats shocked with electricity. The cognitive development of the neonatal rats was assessed by Morris water maze test at 80 days after birth. The brain microdialysis samples of the right hippocampus were collected using a stereotaxic instrument, and the levels of DA and DOPAC were determined by HPLC-ECD. Results Compared with the control group, the mean escape latency of the 80-day-old neonatal rats in the model group was increased. Their swimming speed was slower. The 20% time spent in the peripheral zone became longer, and the frequency of platform crossing was decreased, showing significant differences(P< 0.05). The levels of DA and DOPAC in the extracellular fluid of the hippocampus of the 80-day-old neonatal rats in the model group were decreased at each time points of perfusion, showing a significant difference(P <0.05). The level of DA, a kind of monoamine neurotransmitter in the hippocampus, was positively correlated with the mean escape latency,the frequency of passing the platform of the 80-day-old rats,while was negatively correlated with the 20% time spent in the peripheral zone, with a significant correlation(P < 0.05). In addition, there was a positive correlation between the DOPAC level and the mean escape latency, the frequency of passing the platform(P< 0.05). Conclusions Fear-impaired pregnant rats can affect the spatial learning and memory ability of their 80-day-old neonatal rats,with reduction in the levels of DA and DOPAC in the hippocampus, which is closely correlated with the cognitive development of the neonatal rats.