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Polybrominated diphenyl ethers (PBDEs), used as additive flame-retardants, are increasing in the environment and are present in human mother's milk, newborns and toddlers. We reported earlier that several PBDEs, highly brominated PBDEs, caused developmental neurotoxic effects in mice, manifested as persistent aberrations in spontaneous behaviour, habituation capability, learning and memory, and changes in the cholinergic system.The present study was undertaken to explore the dose–response effects of PBDE 209 on spontaneous behaviour, habituation and its effects on the murine cholinergic system. Neonatal male NMRI mice were given 1.4, 2.3, 14 or 21 μmol PBDE 209/kg body weight, when 3 days old. The agent was administered as a single oral dose via a metal gastric tube. Spontaneous behaviour and response to the cholinergic agonist nicotine were observed in adult mice at 2 and 4 months of age. Mice were also observed for anxiety-like behaviour in an elevated plus-maze. Adult mice, 2 and 4 months old, showed a dose–response related change in spontaneous behaviour, viz. were hyperactive and showed reduced or lack of habituation, effects that worsen with age. At the adult age of 4 months the susceptibility of the cholinergic system was also affected in a dose–response related manner, viz. reduced and/or hypoactive response to nicotine. This shows that PBDE 209 can be as potent as the lower brominated PBDEs in causing developmental neurotoxic defects.

Perfluorinated compounds (PFCs) are found in applications such oil/water repellents for clothing fabrics, carpets, food packaging, lubricants, surfactants and fire extinguishers. PFCs are persistent in the environment. They have been found in humans and in wildlife.

We reported earlier that persistent organic pollutants (POPs), such as DDT, PCBs and BFRs, caused developmental neurotoxic defects in mice, manifested as persistent aberrations in spontaneous behaviour, habituation capability, learning and memory, and changes in the cholinergic system in adults, when mice were exposed during a critical period of neonatal brain development.The present study was conducted to see whether PFCs can cause similar developmental neurotoxic effects as earlier observed for POPs as PCBs and PBDEs. NMRI male mice were exposed to a single-oral dose, either 1.4 or 21 μmol/kg body weight of PFOS (0.75 or 11.3 mg), PFOA (0.58 or 8.70 mg), or PFDA (0.72 or 10.8 mg), via a metal gastric-tube at the age of 10 days. The control animals received in the same manner 10 ml/kg body weight of the 20% fat emulsion vehicle. Spontaneous behaviour (locomotion, rearing, and total activity), and habituation were observed in 2- and 4-month-old mice. The susceptibility of the cholinergic system was explored in a nicotine-induced spontaneous behaviour test in 4-month-old mice. Deranged spontaneous behaviour was observed in mice exposed to PFOS and PFOA, manifested as reduced and/or lack of habituation and hyperactivity in adult mice. These effects were also seen to worse with age. Neonatal exposure to PFOS and PFOA affected the cholinergic system, manifested as a hypoactive response to nicotine, compared to a hyperactive response to nicotine in controls. These developmental neurotoxic effects are similar to those we reported earlier for PCBs and PBDEs. This suggests that PFOS and PFOA be included in the group of POPs known to be developmental neurotoxicants.