The metabolism of plasma glucose and catecholamines in Alzheimer's disease

Several lines of evidence suggest that the cholinergic system in the hippoc ampus plays a pivotal roll in regulating the peripheral metabolism of gluco se and catecholamines. The injection of cholinergic stimulators including n eostigmine, the acetylcholine esterase inhibitor, into the third ventricle or the hippocampus induces the elevation of glucose or catecholamines in pl asma in rats. Under stress conditions, release of acetylcholine in the hipp ocampus increases, which coincides with the elevation of plasma glucose and catecholamines. Age-related reduction in responsivity of the cholinergic s ystem in the hippocampus has been well documented. The intrahippocampal neo stigmine injection induces significantly attenuated responses in plasma glu cose and catecholamines in rats, the finding suggested that changes in chol inergic system activity in the hippocampus could result in alteration of th e peripheral metabolism of glucose and catecholamines. In Alzheimer's disea se (AD), the most common type of dementia, degeneration of the hippocampal cholinergic system is one of the most robust pathological features. Measure ment of plasma catecholamines during a fasting state in the groups of AD su bjects, vascular dementia subjects, and non-demented control subjects showe d significantly lower plasma epinephrine levels in the AD subjects. (C) 200 0 Elsevier Science Inc. All rights reserved.