BACKGROUND: The core symptoms of attention deficit, impulsiveness, hyperactivity of attention deficit hyperactivity disorders (ADHD) can concurrently present in spontaneous hypertensive rats.Neuropathological, biochemical and pharmacological studies also support it. Spontaneous hypertensive rats are one kind of best ADHD animal models, which has been accepted at present. Yizhining elixation can reinforce kidney and calm liver, strengthen spleen and nourish heart, benefit intelligence and focus attention,but its therapeutic effect on treatment of ADHD needs to be further investigated.OBJECTIVE: To observe the effect of Yizhining elixation on the persistent active attention deficit and impulsiveness of rats with spontaneous hypertension.DESIGN: Observational and controlled analysis.SETTING: Department of Pediatrics, the First Affiliated Hospital of Guangzhou University of ChineseMedicine.MATERIALS: Thirty-six male rats with spontaneous hypertension, of clean grade, were involved in this experiment. The involved rats were provided by Shanghai SLAC Laboratory Animal Co., Ltd., and they did not undergo any experiments; Yizhining elixation was composed by Guiban, Shenglonggu, Yuanzhi,Shichangpu, Yejiaoteng, Shudi, Dangshen, Yunling, Fuxiaomai, Wueizi, etc. Crude drug, provided by Outpatient Dispensary, Affiliated Hospital of Guangzhou University of Chinese Medicine, was prepared into water elixation, which contained crude drug of 1.154 g/mL.METHODS: This experiment was carried out in the Department of Pediatrics, First Affiliated Hospital of Guangzhou University of Chinese Medicine between March and July 2005. The involved rats were randomized into 3 groups: Yizhining high dose group, Yizhining low dose group and blank control group, with 12 rats in each. Changes in sustained attention and impulsiveness of rats were detected before and after administration of Yizhining elixation by "5-choice serial response time task" method. Following above-mentioned training and detection, rats in each group were daily drenched with Yizhining elixation once for 14 days successively. Rats in the Yizhining high-dose and low-dose groups were drenched with 12.6 mL/kg and 6.3 mL/kg Yizhining elixation (diluted to 25 mL/kg) respectively, and those in the blank control group were drenched with 12.5 mL/kg normal saline. On the 14th day after administration, the ratios of correct and immature response of rats were re-detected for 3 days successively by formal detection method for later analysis. The sustained attention of rats was evaluated with ratio of correct response: Ratio of correct response=[times of correct response/(times of correct response + times of incorrect response)]; impulsiveness was evaluated with the ratio of immature response: ratio of immature response=[times of immature response/ (times of correct response+times of incorrect response+times of omission+times of immature response) ].MAIN OUTCOME MEASURES: The effects of different doses of Yizhining elixation on the sustained attention (ratio of correct response) and impulsiveness (ratio of immature response) of spontaneous hypertensive rats.RESULTS: Thirty-six spontaneous hypertensive rats were involved in the final analysis. The ratio of correct response of rats in the Yizhining high dose and low dose groups after administration was (98.9 ± 2.30 )% and (96.6± 4.00) %, respectively, which was significantly higher than that before administration [ ( 80.4 ±11.5 ) %, (83.9±8.90) %, P＜ 0.01] and that in the blank control group[ (83.3±6.30) %, P ＜ 0.01]. The ratio of immature response of rats in the Yizhining high dose and low dose groups after administration was (5.04 ± 1.04 ) %, (7.23 ± 1.22) %, respectively, which was lower than that before administration [ (9.85±2.50) %, (9.40±1.73 ) %, P ＜ 0.05] and that in the blank control group [ (9.42 ± 1.64) %, P ＜ 0.01 ].CONCLUSION: Yizhining elixation can improve the sustained attention and impulsiveness of spontaneous hypertensive rats.