TYROSINE INGESTION DURING RAT PREGNANCY ALTERS POSTNATAL-DEVELOPMENT OF DOPAMINERGIC-NEURONS IN THE OFFSPRING

It has been previously reported that tyrosine ingestion by the mother rat during gestation modifies different behavioral patterns in the adu lt offspring. In the present study, the action of maternal mother tyro sine ingestion on the postnatal development of the dopaminergic system of the offspring was evaluated. The offspring of tyrosine-treated mot hers showed a decrease in dopamine (DA) levels during the first 15 day s of postnatal life and an increase in DA levels from day 30 to adulth ood. The DOPAC level and the DOPAC/DA index were higher in the tyrosin e group from postnatal life to adulthood. These differences reach stat istical significance in both forebrain and mesencephalon. During adult hood the DA concentration in both s. nigra and ventral tegmental area were higher in the tyrosine group than in the control group. The behav ioral postsynaptic response to a DA receptor agonist (apomorphine) was higher in the offspring of tyrosine treated rats than in the control group. These data suggest that the bioavailability of the DA precursor tyrosine during gestation may modify during postnatal life DA synapsi s at both pre- and postsynaptic level.