Objective: In order to investigate the mechanism of the improvement of Gastrodia elata (G.E.) on learning and memory impairment of rats exposed to aluminum.
Methods: 36 SD rats, adult and healthy, were divided into 6 groups at random: 1. normal saline, 2. Al3+ 5 mg/kg, 3. Al3+ 10 mg/kg, 4. normal saline +G.E., 5. Al3+ 5 mg/kg +G.E. and 6. Al3+ 10 mg/kg +G.E. Then, they were exposed to AlCl3 by intraperitioneal injection at a dose of 0.2 ml/d, 60 d. G.E. was administered by drinking water at a dose of 0.4 g/kg body weight.
Results: The results of learning and memory were recorded by Step-Down Test. It was showed that compared with the normal saline group, in the group of Al3+ 5 mg/kg, the content of brain cortex aluminum and EN1 increased significantly; the latency (LT) was shortened obviously(P < 0.01); the activity of AChE decreased and the activity of MAO increased (P < 0.01). In the group of Al3+ 10 mg/kg, the content of brain cortex aluminum, EN1 and EN2 increased significantly(P < 0.01), the LT is shortened obviously (P < 0.01), the activity of AChE decreased and the activity of MAO increased (P < 0.01). Compared with the group of Al3+ 5 mg/kg, in the group of Al3+ 5 mg/kg +G.E., EN1 decreased significantly (P < 0.05); the LT is prolonged obviously(P < 0.01), the activity of AChE increased(P < 0.05) and the activity of MAO decreased (P < 0.01). Compared with the group of Al3+ 10 mg/kg, in the group of Al3+ 10 mg/kg +G.E., both EN1 and EN2 decreased significantly(P < 0.01); the LT is prolonged obviously(P < 0.01), the activity of AChE increased (P < 0.01) and the activity of MAO decreased (P < 0.01).
Conclusion: It is suggested that G.E. might decrease the content of brain cortex aluminum of rats. However it might improve the learning and memory ability possibly through regulating the cholinergic system and the monoaminergic system.