Alterations of monoamine metabolites and neurobehavioral function in lead-exposed workers

Neurobehavioral and neurochemical effects of occupational lead exposure were investigated by WHO Neurobehavioral Core Test Battery (NCTB) testing and a series of monoamine neurotransmitters and their metabolites analyzing in workers from lead smeltery and storage-battery manufacturing factory and matched controls. Indicators of lead exposure, the blood lead (PbB) and zinc protophorphyrin (ZPP) levels were found significantly higher in the exposed group compared with that of the controls (70.55 micrograms/dL vs 3.67 micrograms/dL; and 294.92 micrograms/dL vs 38.32 micrograms/dL, respectively). Furthermore, elevated urinary homovanillic acid (HVA) and impairment of certain neurobehavioral performances were also found in the lead exposed workers; the latter included attention/response speed, manual dexterity, perceptual-motor speed, visual perception/memory, and motor speed/steadiness. Positive or negative correlations were observed between certain parameters. Thus, homovanillic acid (HVA) is positively correlated with PbB and ZPP; dopamine (DA) negatively correlated with Benton visual retention (BVR); and HVA negatively correlated with digit symbol (DSy), BVR, and pursuit aiming (PA). It is suggested that the alterations of dopamine and its metabolites HVA in urine associated with impairment of neurobehavioral function might be served as biomarkers of lead-induced neurotoxicity.