“…Indeed, although they are not classical neurotrophic factors, both sets of genes are critical for normal brain development [16,98] and specifically control the architectural development of the hippocampus and neocortex [32,52,54,70,100], two areas that are known to be targeted for disruption by organophosphates [1,65,72,73,91]. There is limited information linking altered expression of specific members of the wnt and fzd families to adverse neurobehavioral outcomes, but it is notable that wnt5a and fzd3, which we found to be reduced by both chlorpyrifos and diazinon, are key determinants in establishing the dopaminergic phenotype [12] and development of dopamine projections [96]. Here again, our results provide strong evidence for parallel or interactive participation of the wnt and fzd pathways with the fgf family, since we previously identified suppression of fgf members associated with the ontogeny of dopamine systems [79], which are especially sensitive to chlorpyrifos [3,25,76,78,80], and which likely underlie the association of organophosphate exposure with the subsequent development of Parkinson's Disease [43,47].…”