Improvement of the cholinergic function by melatonin in amnesic rats induced by amyloid β-peptide 25-35 / 中国药理学通报

ABSTRACT

AIM: To investigate whether melatonin improve the learning and memory dysfunction in the amnesic rats induced by amyloid β-peptide 25-35 (Aβ25-35) via cholinergic nervous system or not. METHODS: The amnesic model in adult rats was induced by injection of Aβ25-35 into hippocampus; Morris water maze was used to determine the effects of Aβ25-35 and melatonin on the learning and memory. The activity of the choline acetyltransferase and acetylcholinesterase were determined by immunohistochemistry and spectrophotometry respectively. RESULTS: Injection of Aβ25-35 20 μginto the adult rats hippocampus induced learning and memory dysfunction, and a decrease in the number of ChAT-immunoreactive neurons in hippocampus. Melatonin (0.1, 1, and 10 mg·kg-1, ig X 10 d) improved the Aβ25-35-treated rats cognitive function and increased the number of ChAT-immunoreactive neurons in hippocampus. CONCLUSION: Improvement of the cholinergic dysfunction by melatonin in adult rats induced by amyloid β-peptide 25-35 may be via cholinergic nervous system.