BDNF and neuroblastoma: Similarly, chlorpyrifos and parathion treatment in young rats was reported to decrease neurotrophic factors, such as NGF and brain-derived neurotrophic factor, in the hippocampus and cerebral cortex.39 NGF-mediated neuroprotection via the TrkA receptor enhances neurite outgrowth in human neuroblastoma cells, which is blocked by organophosphate drugs.40 Unfavorable environmental conditions surrounding neuronal cells may promote neuronal cell death.