[The effect of a new antiparkinson agent, Selegilin, on psychomotor performance in humans]

A combination of tests consisting of a compensation task with differential value indication, a tachystoscopic arrangement with verbal identification of characteristic features and an arrangement for a visually induced motor reaction was carried out on 12 healthy volunteers aged from 20-30 to determine psychomotor efficiency under the influence of the new antiparkinson drug selegiline (Eldepryl). The results were compared with the effects of the psychostimulant fenetylline and the depressant-antihistamine chlorphenoxamine, and with a placebo. While fenetylline and chlorphenoxamine produced the anticipated effects with regard to an improvement or deterioration in performance in all parameters, selegiline resulted in a slightly longer motor reaction time and an increase in control errors, and in a significantly longer mental processing time. In comparison with the placebo, selegiline increased the motor reaction time by 0.8 +/- 1.95% and mental processing time by 4.1 +/- 1.7%. This depressant effect of selegiline, however, only attained 1/8 and 2/3, resp., of the sedative effect of the normal dose of the antihistamine chlorophenoxamine. Under the influence of chlorphenoxamine, performance becomes less regular and under fenetylline more regular. Selegiline does not differ significantly from the placebo. In spite of selegiline metabolites 1-metamphetamine and 1-amphetamine, which act as mild stimulants, the slightly depressant effect of selegiline detected can be explained by the increased effect of dopamine inhibitory neurons, particularly in the inhibitory system of the formatio reticularis and the cortex frontalis as a result of a concentration of dopamine.