Effect of neurosteroid dehydroepiandrosterone on the higher nervous activity of old non-human primates

The results of studies on the biological effects of the prolonged administration of physiological doses of dehydroepiandrosterone (DHEA) on behavior and state of the higher nervous activity (HNA) in old rhesus macaques that had reached the limit of biological age are presented. HNA was investigated using the procedure of motor-alimentary conditioned reflexes, which allows assessing the long-term (conditioned-reflex) memory in animals. The state of short-term (working) memory was evaluated using the test of delayed response performance. DHEA was administered intramuscularly in peach oil at a dose of 1 mg/kg every two days for three months. DHEA at the doses used improved HNA and balanced the excitatory and inhibitory processes in the brain. The motor activity and alimentary motivation were increased. The woolliness lost was restored in old monkeys under the action of DHEA; this effect persisting for a year.