Effect of BMY 21502 on classical conditioning of the eyeblink response in young and older rabbits.

BMY 21502, a substituted pyrrolidionone, has been found to enhance a simple form of learning in older rabbits. In humans, this simple type of learning, classical conditioning of the eyeblink response, declines in normal aging and is seriously impaired in Alzheimer's disease (AD). We have demonstrated that eyeblink classical conditioning reliably discriminates patients diagnosed with probable AD from non-demented, age-matched elderly subjects. Older organisms can be classically conditioned, but they condition at a much slower rate than younger organisms. Our preliminary analyses indicate age differences in distribution of protein kinase C in the hippocampus. Here we also report that older rabbits that are administered two different doses of BMY 21502 classically condition at a rate approximating that of young rabbits.