Objective: To study the regulation effect of Anshen Dingzhiling (ADL) on tyrosine hydroxylase (TH)

DOPA decarboxylase (DDC)

and protein kinase A (PKA)

and reveal the effect mechanism of Anshen Dingzhiling in treatment of attention deficit hyperactivity disorder (ADHD). Method: Spontaneously hypertensive (SHR) rats were divided into model group

western medicine group

ADL high

medium and low dose (26.70

13.35

6.75 g·kg-1) groups based on random number

n=8 in each group. Another 8 WKY rats were set as normal group. The rats in each group received lavage administration for 4 weeks. Brain synaptosome was prepared by using Percoll density gradient centrifugation method. Western blot method was used to detect the protein expression levels of TH and PKA;Real-time polymerase chain reaction (Real-tim PCR) technique was used to detect mRNA expression levels of TH

DDC

PKA; and immunofluorescence technique was used to detect TH

and DDC positive cells expression. Result: As compared with normal group

the synaptic TH

DDC

and PKA expression levels were significantly reduced in model group (P<0.01);as compared with model group

the synaptic TH

PKA protein expression levels

TH

PKA

DDC mRNA expression levels

and number of positive cells were increased in western medicine group and ADL medium dose group (P<0.05). Immunohistochemistry positive cell count results showed that as compared with normal group

TH positive cells expressing level was significantly reduced in model group and ADL high dose group (P<0.01)

and TH positive cells expressing level was reduced in ADL low dose group (P<0.05); DDC positive cells expressing level was significantly reduced in model group and ADL low dose group (P<0.01). As compared with model group

TH positive cells expressing level was significantly increased in western medicine group and ADL low dose and medium dose groups (P<0.01); in addition

number of DDC positive cells was increased significantly in the western medicine group and ADL medium and high dose groups (P<0.01). Conclusion: ADL could affect the speed of dopamine synthesis through regulating the expression of TH

DDC

PKA

and the effect of ADL for core symptoms of ADHD may be related to the regulation of dopamine synthesis speed.