Neonatal exposure to neurotoxic pesticides increases adult susceptibility: a review of current findings.

An environmental mischance commonly occuring in nature is the combination of neonatal exposure and later adult exposure to various toxic substances. During neonatal life, offspring can be affected by toxic agents either by transfer via mother's milk or by direct exposure. In many mammalian species the perinatal period is characterized by a rapid development of the brain--'the brain growth spurt' (BGS). We have observed that exposure to pesticides, such as DDT and bioallethrin, during the BGS in mice can potentiate susceptibility to bioallethrin or paraoxon in adult life. This combined neonatal and adult exposure caused spontaneous behavioural aberrations and changes in muscarinic cholinergic receptors and led to impairment of the faculties of learning and memory. Our studies indicate that neonatal exposure to pesticides--even in low doses--can potentiate and/or modify the reaction to adult exposure to xenobiotics, and thereby accelerate dysfunctional processes.