Neurodevelopmental evaluation of 9-month-old infants exposed to low levelsof lead in utero: Involvement of monoamine neurotransmitters

The objective of this work is to investigate the neurotoxicty of low-level lead exposure in utero on infants and the possible involvement of dopaminer gic a,nd serotonergic neurotransmitters, The correlation analysis for cord blood lead level, the concentrations of dopamine metabolite homovanillic ac id (HVA) and serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in co rd plasma and the neurodevelopmental scales of infants were conducted on 24 4 9-month-old children. Both score of sociability subscale and 5-HIAA conce ntration were correlated with cord blood lead level. The sociability score was negatively correlated with the concentration of HVA, whereas both the c oordination score and the global score were negatively correlated with the concentration of 5-HIAA. With partial correlation analysis, after taking HV A into account, the significant negative correlation between the sociabilit y score and the cord blood lead level that existed in the linear correlatio n,analysis disappeared, and the score of global scale correlated negatively with lead level in cord blood. When taking 5-HIAA into account, the scores of all the neurodevelopmental subscales except the language subscale were significantly negatively correlated with lead level in cord blood. The resu lts indicated that low-level lead exposure in utero could produce a neuroto xic effect on the developing serotonergic system in infants. The neurotoxic ity of low-level lead exposure in utero may affect the sociability of infan ts. Serotonergic activity was shown to have a potential effect on neurodeve lopmental assessment. If may interfere with the association between low-lev el lead exposure in utero and other neurodevelopmental performances of 9-mo nth-old children. Copyright (C) 1999 John Wiley & Sons, Ltd.