MATERNAL INGESTION OF TYROSINE DURING RAT PREGNANCY MODIFIES THE OFFSPRING BEHAVIORAL LATERALIZATION

It was previously reported that oral administration of tyrosine (500 m g/kg) to pregnant rats increases tyrosine and monoamines level in the fetal brain and modifies locomotion during postnatal life. In the pres ent study, it was found that this treatment alters behavioral laterali zation in the offspring. Neonatal rats whose mothers received tyrosine during the second half of gestation showed a low level of absolute an d population laterality in both tail and head movements. The alteratio n of behavioral lateralization was also found during postnatal develop ment and during adulthood. The T-maze behavioral ontogeny was differen t for tyrosine-mother and sham-treated or untreated mother rats. Durin g adulthood, the T-maze lateralization after stress sessions (a proced ure that decreases alternation behavior and facilitates the quantifica tion of behavioral lateralization) was also different in control and t yrosine-mother groups. Neonatal and adult rats showed an increase in r ight-side movements probability. These data provide evidence that mate rnal ingestion of a catecholamine precursor during gestation may induc e a long-lasting modification of the behavioral lateralization of the offspring.