Objective To explore the potential mechanism of Yizhi Ningshen Granules（ 益智宁神颗粒

YNG） in the treatment of attention deficit hyperactivity disorder（ ADHD）. Methods Forty juvenile spontaneously hypertensive rats（ SHR） were randomized into the model group

YNG group

methylphenidate group and Tomoxetin group

with 10 rats in each group. Another 10 WKY rats were selected as the normal group. The YNG group was given 3. 75g/100 g of YNG solution（ 3. 75 g/ml） by gavagy

the Methylphenidate group was administered 5 mg/（ kg · d） of Methylphenidate Hydrochloride Extended-release Tablets by gavage

the Tomoxetin group was given 0. 3 mg/（ kg·d）of Atomoxetine Hydrochloride Capsules by gavage

and the normal group and the model group were given 2 mg/100 g of 0. 5% normal saline by gavage. Each group was treated once a day for 28 days. The cerebral hippocampal dopaminergic neuronal morphology

the expression of glial cell line-derived neurotrophic factor（ GDNF）

positive cell count and mRNA expression were detected in each group. Results It was observed under electron microscope that the damage of mitochondria and other structures in the hippocampal dopamine neurons in YNG group was less serious than those in the model group. The expressions of GDNF protein and mRNA in hippocampus in the YNG group

the Tomoxetin group and the Methylphenidate group were significantly higher than those in the model group（ P < 0. 05）.The level of GDNF mRNA in the Tomoxetin group was higher than that in the YNG group and the Methylphenidate group（ P < 0. 05）. There was no significant difference in GDNF positive cell count among all groups（ P > 0. 05）.Conclusion YNG could alleviate the damage of dopamine neurons in hippocampus of SHR rats and improve the expressions of GDNF protein and its mRNA

which may be one of its mechanism.