Cholinergic activity of aged rhesus monkeys revealed by positron emission tomography

In the present study, the radiotracer [F-18](+)-4-fluorobenzyltrozamicol (( +)-[F-18]FBT) and positron emission tomography (PET) were used to examine t he vesicular acetylcholine transporter and determine if presynaptic choline rgic activity was altered with age in 23 rhesus monkeys that varied in age from 10 to 37 years. Binding of (+)-[F-18]FBT in the basal ganglia was redu ced significantly with increasing age of the monkeys. However, there were i ndividual differences noted in that some middle-aged and aged monkeys demon strated levels of (+)-[F-18]FBT binding that were comparable to the binding measured in adult monkeys. These data indicate that presynaptic cholinergi c function may decrease with age, but that there may be a differential susc eptibility of the cholinergic system to the aging process in different indi viduals. (C) 2001 Wiley-Liss, Inc.