[The changes of peripheral-central nervous system interaction in Alzheimer's disease]

Several lines of evidence suggest that the cholinergic system in the hippocampus plays a pivotal roll in regulating the peripheral metabolism of glucose and catecholamines. The injection of cholinergic stimulators including neostigmine, the acetylcholine esterase inhibitor, into the third ventricle or the hippocampus induces the elevation of glucose or catecholamines in plasma in rats. Under stress conditions, release of acetylcholine in the hippocampus increases, which coincides with the elevation of plasma glucose and catecholamines. Age-related reduction in responsivity of the cholinergic system in the hippocampus has been well-documented. The intrahippocampal neostigmine injection induces significantly attenuated responses in plasma glucose and catecholamines in rats, which finding suggested that changes in cholinergic system activity in the hippocampus could result in alteration of the peripheral metabolism of glucose and catecholamines. In Alzheimer's disease, the most common type of dementia, degeneration of the hippocampal cholinergic system is one of the most robust pathological features. Measurement of plasma catecholamines during a fasting state in groups of Alzheimer's disease subjects, vascular dementia subjects, and non-demented control subjects showed significantly lower plasma epinephrine levels in the Alzheimer's disease subjects.