Regulatory Effect of Polygala tenuifolia and Licorice-simmered P. tenuifolia on Learning and Memory， HPA Axis Function and Neurotransmitters in Rats with Heart-kidney Imbalance Insomnia / 中国实验方剂学杂志

ABSTRACT

Objective:To compare the regulatory effects of <italic>Polygala tenuifolia</italic> and licorice-simmered <italic>P. tenuifolia</italic> on learning and memory， hypothalamus-pituitary-adrenal axis （HPA axis） function and neurotransmitters in rats with heart-kidney imbalance insomnia. Method:The rat model of insomnia induced by multi-factor stimulation was established. After the model being made， the administration groups were given the extracts of <italic>P. tenuifolia</italic> and licorice-simmered <italic>P. tenuifolia</italic> by gavage （dose of 8 g·kg^-1·d^-1）， while the normal group and model group were given the same volume of normal saline for 7 days. Morris water maze was used to detect the changes of learning and memory ability of rats in each group. Enzyme-linked immunosorbent assay （ELISA） was used to determine the levels of corticotropin-releasing hormone （CRH）， adrenocorticotropic hormone （ACTH） and cortisol （CORT） in serum of rats from each group. The contents of 5-hydroxytryptamine （5-HT）， dopamine （DA）， <italic>γ</italic>-aminobutyric acid （GABA） and glutamic acid （Glu） in the hypothalamus of rats were determined simultaneously by ultra performance liquid chromatography tandem mass spectrometry （UPLC-MS/MS）. Result:Compared with the normal group， the spatial learning and memory ability of rats in the model group<italic> </italic>was decreased， the times and time of staying in target quadrant were significantly reduced （<italic>P<</italic>0.05， <italic>P<</italic>0.01）， the levels of CORT， CRH and ACTH in serum were significantly increased （<italic>P<</italic>0.01）， the contents of GABA， DA， 5-HT in hypothalamus tissue were significantly decreased （<italic>P<</italic>0.01）， and the content of Glu was significantly increased （<italic>P<</italic>0.01）. Compared with the model group， the spatial learning and memory ability of rats in the <italic>P. tenuifolia</italic> group and licorice-simmered <italic>P. tenuifolia </italic>group<italic> </italic>were increased， the times and time of staying in the target quadrant were significantly increased （<italic>P<</italic>0.05， <italic>P<</italic>0.01）， the levels of CORT， CRH and ACTH in serum were significantly decreased （<italic>P<</italic>0.05， <italic>P<</italic>0.01）， the contents of GABA， DA and 5-HT in hypothalamus tissue were significantly increased （<italic>P<</italic>0.05， <italic>P<</italic>0.01）， and the content of Glu was significantly decreased （<italic>P<</italic>0.05）. The recovery degree of each index in the licorice-simmered <italic>P. tenuifolia</italic> group was better than that in the <italic>P. tenuifolia</italic> group. Conclusion:Both <italic>P. tenuifolia</italic> and licorice-simmered <italic>P. tenuifolia</italic> can improve the learning and memory ability， improve the function of HPA axis， regulate the level of central neurotransmitters， and have the effect of calming the mind and improving the intelligence of rats with heart-kidney imbalance insomnia. The effect of licorice-simmered <italic>P. tenuifolia</italic> is better than that of <italic>P. tenuifolia.</italic>