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The striatal
dopamine dependency of life span in male rats. Longevity study with
(-)deprenyl.
Knoll J
Department of Pharmacology
Semmelweis University of Medicine,
Budapest, Hungary.
ABSTRACT
Long-term experiments on male rats revealed that better performers in the mating test are
better learners in the shuttle box and the more active animals live significantly longer
than their less active peers. It was established by the aid of (-)deprenyl, a highly
specific chemical tool, which increases superoxide dismutase activity in the striatum,
facilitates the activity of the nigrostriatal dopaminergic neurons with utmost
selectivity, and protects these neurons from their age-related decay, that the efficiency
of a male rat in behavioral tests, as well as the duration of its life are striatal
dopamine dependent functions. As a measure of striatal function, sexual activity was
tested once a week in a group of male rats (n = 132) from the 24th month of their life.
Because of the age-related decay of this function none of the 2-year-old animals displayed
full scale sexual activity. By dividing the group equally the rats were treated with
saline (1 ml/kg, s.c.) and deprenyl (0.25 mg/kg, s.c.), respectively, three times a week.
In the saline-treated group (n = 66) the last signs of sexual activity vanished to the
33rd week of treatment. (-)Deprenyl treatment
restored full scale sexual activity in 64 out of 66 rats.
The longest
living rat in the saline-treated group lived 164 weeks. The average lifespan of the group
was 147.05 +/- 0.56 weeks. The shortest living animal in the (-)deprenyl-treated group
lived 171 weeks and the longest living rat died during the 226th week of its life.
The
average lifespan was 197.98 +/- 2.36 weeks, i.e. higher than the estimated maximum age of
death in the rat (182 weeks). This is the first instance that by the aid of a well-aimed
medication members of a species lived beyond the known lifespan maximum.
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