Abstract: ObjectiveTo observe the influence of mitochondrial cytochrome c oxidase(COX) decrease on cholinergic and dopaminergic system in brain of model rats.MethodsRats were administrated with 1mg/kg/h or 2mg/kg/h subcutaneously via an Alzet minipump for 30 days. Choline-acetyl-transfertase(ChAT) and acetylcholinesterase(AChE) activity in hippocampus and cortex of rats were measured by radiochemical method and hydroxylamine colorimetry separately. The contents of Norepinephrine(NE), dopamine, 5-hydroxytryptamine(5-HT) and their metabolic products in striatum were measured by HPLC.ResultsChAT activity was significantly inhibited in hippocampus and cortex of model rats, however, the activity of AChE increased in hippocampus and was not affected at the cortex. Therefore, the ratio of ChAT/AChE decreased in model rats. The content of NE, dopamine, 5-HT and their metabolic products in striatum were not different among all groups.ConclusionsCOX deficiency can induce abnormality of ChAT and AChE activity in model rats. Dysfunction of neurotransmitter-acetylcholine would be account for learning-memory deficiency. Model rats indicated cholinergic system deficit without any dopaminergic system abnormality, so chronic infusion of sodium azide via minipump may specially serve as a tool for developing the experimental model of Alzheimer's disease.

Key words: sodium azide, learning-memory, mitochondria, choline-acetyl-transfertase, acetylcholinesterase, monoamine, rats