Depletion and recovery of neuronal monoamine storage in rats of different ages treated with reserpine.

The effect of reserpine on dopamine, noradrenaline, adrenaline and serotonin concentrations in different brain regions, and the recovery of normal levels of these monoamines after such treatment were studied in rats aged 5, 15 and 27 months. In a preliminary experiment we found that distribution of the drug was not altered in the aged rats. Then we observed that a single dose of reserpine (5 mg/kg IP) had a similar depleting effect on all the brain monoamines, in all the brain regions considered in all three age groups. The curves expressing recovery of monoamine storage in all the nerve terminals, several days after treatment, were superimposable. These results suggest that in the rat, age does not influence the effect of reserpine on the storage mechanism of brain monoamines. Moreover, as restoration of this mechanism depends on the synthesis of new vesicles, the similarity in the rates of recovery in adult, old and very old rats indicated indirectly that synthesis of these neuronal organelles is not affected by aging.