Lack of efficacy of clonidine on memory in aged cebus monkeys.

Using a dosing paradigm and an automated behavioral testing procedure designed to maximize potential drug efficacy, we evaluated the ability of clonidine to improve performance of aged monkeys on a trial-specific memory task. These results indicated that neither acutely administered (0.0025-0.04 mg/kg) or subchronically administered (0.01-0.06 mg/kg for 3 consecutive days) clonidine improved the performance of aged monkeys. These data are discussed in view of previously reported, conflicting data, as well as their implication regarding probable neurochemical factors involved in age-associated memory impairment and approaches to future palliative treatments.