1991 Volume 28 Issue 3 Pages 345-350
Alzheimer's disease is one of the main causes of senile dementia. Although its pathogenesis is not clear, some evidence has revealed that the activity of acethylcholine receptor in the brains of these patients is decreased. In the present study, possible circulating factors, affecting the muscarinic acethylcholine receptor of the synaptic vesicle from the rat brain, were evaluated in the serum of 95 senile subjects (34 males and 61 females, mean±SD age of 77.5±8.6 years). The cognitive function of these subjects was assessed by their Mini-Mental State scores, and they subjects were divided into non-dementic-subjects with a score of 21 or more, or subjects with dementia with a score of 20 or less. The latter were further divided into senile dementia with Alzheimer type (SDAT) and vascular type dementia (VS) using Hatchinski's ischemic score. The mean suppression rate by the serum from the SDAT patients on the binding of tritiated quinuclidinyl benzilate (3H-QNB), an antagonist for muscarinic acethylcholine receptor, to the rat synaptic membrane, was 18.1±7.2% of the control value, which was significantly greater than that of the non-dementic subjects, (4.7±3.8%). However, that in the VD group (8.4±6.8%), was not significantly different from the control value. Moreover the suppression rate of the serum on 3H-QNB binding showed significant positive correlated with score for the Mini-Mental State (r=0.480, p<0.01) in the SDAT group. These data support the hypothesis that circulating suppression factors may participate in the pathogenesis of SDAT.
