Improvement of the cholinergic function by melatonin in amnesic rats induced by amyloid ?-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 ? peptide 25～35 (A? 25～35 ) via cholinergic nervous system or not.Methods The amnesic model in adult rats was induced by injection of A? 25～35 into hippocampus; Morris water maze was used to determine the effects of A? 25～35 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 A? 25～35 20 ?ginto 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?10 d) improved the A? 25～35 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 ? peptide 25～35 may be via cholinergic nervous system.