Change in nicotinic receptor subtypes in temporal cortex of Alzheimer brains.

Competition experiments using (-)-[3H]nicotine and unlabelled nicotine revealed both high and low affinity nicotinic binding sites in temporal cortex of control and Alzheimer (AD/SDAT) brains. A significant reduction in the proportion of high affinity nicotinic binding sites (-20%) and a parallel increase in the proportion of low affinity nicotinic binding sites was obtained in AD/SDAT brain cortex compared to control brain. Moreover, a marked decrease was observed in the affinity of the low affinity nicotinic binding sites in AD/SDAT.