Prolongation of life in an experimental model of aging in Drosophila melanogaster.

(R)-Deprenyl, the archetypical monoamine oxidase-B inhibitor, has been shown to increase life-span in a number of species. Although many theories for this effect have been suggested, for example, an increase in superoxide dismutase (SOD) activity, the mechanism of action has yet to be elucidated. To investigate this phenomenon, we have examined the effects of (R)-deprenyl, and some aliphatic propargylamines, in an experimental aging model in Drosophila melanogaster. Both wild-type Oregon-R type flies, as well as a SOD knock-out mutant strain were used. Flies obtained from a series of paired mates were divided equally among treatment groups. In all studies, flies were treated for the duration of life following adult emergence. The aging model consists of substitution of sucrose with galactose in the regular food media of the flies. Initial experiments confirmed that such a substitution resulted in a significant (p < 0.01, Breslow test) reduction in mean and maximal life-span of flies, an effect not due to nutrient deprivation. Inclusion of (R)-deprenyl and the aliphatic propargylamines in the media, at average daily doses in the range 0.5-1 ng/fly/day, led to a significant increase in mean and maximal life-span of galactose-treated, but not control flies. This effect was seen in both wild-type and mutant flies.