The mechanism by which polychlorinated biphenyls (PCBs) might affect the developing nervous system and result in behavioral and developmental problems in children has been poorly understood. Now, 3 recent studies by US researchers provide insight into the effects of PCBs on brain cell development.
One study found that in utero and neonatal exposure to PCBs enhanced basal dendritic growth but decreased experience-dependent dendritic plasticity in rats (Yang D et al. Environ Health Perspect. 2009;117:426-435). A second study showed that PCBs affected the excitability of neurons in hippocampal rat brain tissue by altering the calcium ion homeostasis through activity at the ryanodine receptors, a class of intracellular calcium channels (Kim KH et al. Toxicol Appl Pharmacol. doi:10.1016/j.taap.2009.03.002 [published online ahead of print March 13, 2009]). The third study showed that PCBs can stabilize ryanodine receptors in an open position, which could explain why PCBs result in overexcitation of neural circuits (Samsó M et al. PLoS Biol. 2009;7:e1000085 [published online April 14, 2009]).
Mitka M. PCBs and Brain Cells. JAMA. 2009;301(21):2202. doi:10.1001/jama.2009.760