Age-dependent alteration in metabolism of vitamin B-6, neurotransmitters, and amino acids after 4 '-O-methylpyridoxine administration in rats

4'-O-methylpyridoxine (MPN), a recognized antivitamin B-6 compound, is a potentially poisonous substance found in Ginkgo biloba L. In this work, the effects of MPN on the metabolism of vitamin B-6, neurotransmitters, and amino acids were compared in the plasma and brain of young and adult rats under various administration times. Results showed that the contents of MPN residues in the plasma and brain of young rats were 12.72 and 14.76 mu M higher than adult rats, respectively. Moreover, the levels of 5-hydroxytryptamine and dopamine in the brain of young rats have decreased by 13.78% and 7.19%, respectively, compared with the control group, at 2 h after MPN administration. Furthermore, the principal component analysis revealed that MPN was an important contributor to the amino acid composition in the brain of young rats. These results suggest that age may lead to different toxic effects of MPN.