Developmental Neurotoxicology

Exposures to developmental neurotoxins are believed to be responsible for the staggering numbers of affected children. In the United States, 5-10% of public school children have learning disabilities, up to 17% of children suffer from attention deficit hyperactivity disorder (ADHD), approximately 1% of all children are mentally retarded and as many as 1 in 150 children born have autismJ5-6 Though some of these effects are genetically influenced, the available evidence suggests that environmental exposures and not genetics are the primary causes for these disorders. 5  

A large number of individual chemicals are recognized developmental neurotoxins. These include heavy metals, alcohol, and other solvents, recreational drugs (e.g., nicotine and cocaine), pesticides, and some pharmaceuticals. Table 19.1 contains a partial list of these and some of the effects ascribed to them.fi 5 7-21  

Though most environmental exposures are to mixtures, most developmental neurotoxicity studies have addressed only single chemicals. Only a very few have addressed the 

Human Toxicology ot Chemical Mixtures. DOI 10.1016/B978-1-4377-M63-8.00019-9 2011 Elsevier Inc, All rights reserved. 

Mercury Motor dysfunction Learning and memory disabdities 

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Aschner M. 1998. Blood-brain barrier physiological and functional considerations. In Handbook of developmental neurotoxicology, p. 339-351. 

Nelson BK. 1985. Developmental neurotoxicology of environmental and industrial agents. In Blum, Manzo. Drug and chemical toxicology series No. 3. Neurotoxicology (Marcel Dekker) 163-201. 

Eriksson P (1996) Developmental neurotoxicology in the neonate-effects of pesticides and polychlorinated organic substances. Arch Toxicol Suppl 18 81-88 Eriksson P, Viberg H, Fischer C, Wallin M, Frediiksson A (2002) A comparison of developmental neurotoxic effects of hexabromo cyclododecane, 2,2, 4,4, 5,5 -hexabromodiphenylether (PBDE 153) and 2,2, 4,4, 5,5 -hexachlorobiphenyl (PCB 153). Organohalogen Comp 57 389-392... 

Nelson BK. 1986. Developmental neurotoxicology of in ulero exposure to industrial solvents in experimental animals. Neurotoxicology 7 441-448. 

Rodier PM (1986) Time of exposure and time of testing in developmental neurotoxicology. Neurotoxicology. 7 69-76. 

Tilson HA (1998) The concern for developmental neurotoxicology Is it justified and what is being done about it Environ Health Perspect, 103 147-151. 

Tilson HA. 1992. Study design considerations in developmental neurotoxicology. Neurotoxicol Teratol 14 199-203. 

Bennett GD Finnell GD (1998) Periods of susceptibility to induced malformations of the developing mammalian brain. In Slikker WJ Chang LW eds. Handbook of developmental neurotoxicology. San Diego, CA, Academic Press, pp 189-208. 

Schardein, J.L. 2000. Chemically-induced Birth Defects. 3rd Ed. New York Marcel Dekker. Schardein, J.L. 1998. Animal/human concordance. Pp. 687-708 in Handbook of Developmental Neurotoxicology, W. Slikker Jr., and L.W. Chang, eds. San Diego, CA Academic Press. Schultz, T.W., H. Witschi, L.H. Smith, W.M. Haschek, J.M. Holland, J.L. Epler, R.J. Fry, T.K. Rao, F.W. Larimer, and J.N. Dumont. 1981. Health Effects Research in Oil Shale Development. Technical Report No. ORNL/TM-8034. Oak Ridge National Laboratory, Oak Ridge, TN. Schwetz, B.A., R.E. Morrissey, F. Welsch, and R.A. Kavlock. 1991. In vitro teratology. Environ. Health Perspect. 94 265-268. 

Jensen KF, Catalano SM. Brain morphogenesis and developmental neurotoxicology. In Slikker W, Chang LW, eds., Handbook of Developmental Neurotoxicology. San Diego Academic Press 1998 3-41. 

Harry GJ (1994) Developmental Neurotoxicology. Boca Raton, FL GRG Press. 

Rice DC (1998) Issues in developmental neurotoxicology interpretation and implications of the data. Can J Public Health 89(Suppl 1) S31-S40... 

Dow Chemical. 1993. Examination of rats for developmental neurotoxicological effects from maternal exposure to 1,1,1-trichloroethane. [Peer reviewed unpublished study]. 

Eriksson P. 1996. Developmental neurotoxicology in the neonate-effects of pesticides and polychlorinated organic substances. Arch Toxicol Suppl 18 81-88. 

Stross JK, Smokier IA, Isbister J, et al The human health effects of exposure to poly-brominated biphenyls. Toxicol Appl Pharmacol 58 145-150, 1981 Tilson HA, Harry GJ Developmental neurotoxicology of polychlorinated biphenyls and related compounds, in The Vulnerable Brain and Environmental Risks, Vol 3 Toxins in Air and Water. Edited by Isaacson RL, Jensen KF. New York, Plenum, 1994, pp 267-279... 

On this basis, developmental neurotoxicological effects, along with any anatomical and other evidence of such neurotoxicity, seen in in utero and with early postnatal exposures, appear first. 

Aschner, M., 1998. Blood-43rain barrier Physiological and functional consideration. In Slicker, W.J. (Ed.), Handbook of Developmental Neurotoxicology Academic Press, San Diego, CA, pp. 339—351. 

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