Table 5.

Experimental evidence of OP effects on neuroplasticity

OP	Model	Exposure Paradigm	Key Findings	Reference
PTH, FEN	Chick DRG explant	1 µM, 72 h	↓Cell membrane integrity; retraction of pseudopodia, induction of lipid vacuoles, lipid accumulation, disruption of tubular structures in growth cone	(223)
CPF/CPO	Neonatal rat	Oral; 1.5 or 3 mg·kg−1·day−1 CPF, 0.25 or 0.35 mg·kg−1·day−1 CPO, PND 1–6	CPF but not CPO ↓forebrain NGF expression	(18, 19)
CPF/CPO	Rat SCG primary neuronal cell culture	0.001–1 µM CPF, 0.001–1 nM CPO	↓Axonal outgrowth but enhanced BMP-induced dendritic growth	(116)
CPF, Methyl-PTH	Neonatal rat	Oral, 4 or 6 mg/kg CPF, 0.6 or 0.9 mg/kg methyl-PTH, PND 10–20	↑NGF and BDNF expression in multiple brain regions; ↑marker of neuronal activity in hippocampus and cortex	(20)
CPF, DZN	Neonatal rat	sc, 1 mg/kg CPF, 1 or 2 mg/kg DZN, PND 1–4	↓Transcripts of neurotrophic growth factors in the FGF family in multiple brain regions	(211)
CPF	Rat	sc, 2.5–18 mg/kg, every other day for 30 days	↓NGF expression in multiple brain regions, ↓in axonal transport in sciatic nerves ex vivo	(219)
CPF/CPO	Rat DRG primary neuronal cell culture	0.001–10 µM CPF, 0.001–10 nM CPO, 24 h	↓Axonal outgrowth	(244)
CPF/CPO	Zebrafish	0.003–1 µM, 24–72 h	CPO but not CPF ↓axonal growth of sensory neurons and motor neurons and affected swimming behavior	(245)

BDNF, brain-derived neurotrophic factor; BMP, bone morphogenetic protein; CPF, chlorpyrifos; CPO, chlorpyrifos-oxon; DRG, dorsal root ganglion; DZN, diazinon; FEN, fenthion; FGF, fibroblast growth factor; NGF, nerve growth factor; OP, organophosphorus pesticide; PND, postnatal day; PTH, parathion; SCG, superior cervical ganglia.