Maternal caffeine ingestion increases the tyrosine level in neonatal rat cerebrum

The cerebral free amino acids in neonatal rats, from dams given 0.04% caffeine in the drinking fluid ad libitum before and/or during pregnancy throughout the lactational period, were examined on days 1, 5 and 10. Significantly reduced cerebral weight was observed on day 1 with a mean caffeine level of 7 micrograms/g wet weight. The tyrosine concentration in the cerebrum, but not that in the liver, was increased on days 1 and 5 with approximate mean caffeine levels of above 1.5-2.0 micrograms/g wet weight. The tyrosine level showed a positive correlation with the caffeine level in neonatal cerebrum only on day 1 in the group with caffeine ingestion after pregnancy. There was no significant increase in the fetal cerebral concentration of MOPEG-SO4 on day 5 with maternal caffeine. These results suggest that maternal caffeine disturbs the neonatal cerebrum through tyrosine and tyrosine hydroxylase, and then produces behavioral abnormalities in developing rats.