PCBs May Alter in utero Neonatal Brain Development
Isaac N. Pessah, Ph.D.
University of California Davis
NIEHS Grants P01ES011269, Ro1ES014901, and P42ES004699
In three new studies, NIEHS grantees at the University of California Davis provide evidence of how low-level exposure to polychlorinated biphenyls (PCBs) alters the normal development of brain cells. These findings could help to explain the relationship between PCB exposure and neurodevelopmental and behavioral disorders in children.
Although banned 30 years ago, researchers have never understood the mechanism by which PCBs produce neurological problems in children. The researchers exposed laboratory rats to low levels of two structurally different PCBs and examined the hippocampus, a region of the brain involved in memory and learning. They found that PCB exposure locks ryanodine receptors, a class of intracellular calcium channels that control the electrical excitability of neurons, into the "on position" thus altering their excitability. Additional in vitro studies confirmed the results.
The team plans to conduct additional studies in mice that carry some of the same genetic variations of the ryanodine receptors that humans exhibit. Those studies will be important to determine whether there are people who are genetically susceptible to PCB toxicity.
Citation: Kim KH, Inan SY, Berman RF, Pessah IN. Excitatory and inhibitory synaptic transmission is differentially influenced by two ortho-substituted polychlorinated biphenyls in the hippocampal slice preparation. Toxicol Appl Pharmacol. 2009 Jun 1;237(2):168-77.
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