(SACRAMENTO, Calif.) New research from UC Davis and Washington State University shows that PCBs, or polychlorinated biphenyls, launch a cellular chain of events that leads to an overabundance of dendrites the filament-like projections that conduct electrochemical signals between neurons and disrupts normal patterns of neuronal connections in the brain.
"Dendrite growth and branching during early development is a finely orchestrated process, and the presence of certain PCBs confuses the conductor of that process," said Pamela Lein, a developmental neurobiologist and professor of molecular biosciences in the UC Davis School of Veterinary Medicine. "Impaired neuronal connectivity is a common feature of a number of conditions, including autism spectrum disorders."
Reported today in two related studies in the journal Environmental Health Perspectives, the findings underscore the developing brain's vulnerability to environmental exposures and demonstrate how PCBs could add to autism risk.
"We don't think PCB exposure causes autism," Lein said, "but it may increase the likelihood of autism in children whose genetic makeup already compromises the processes by which neurons form connections."
The senior authors of the studies were Lein and Isaac Pessah, chair of molecular biosciences in the School of Veterinary Medicine and director of the Center for Children's Environmental Health at UC Davis. Both are researchers with the UC Davis MIND Institute, which is dedicated to finding answers to autism and other neurodevelopmental disorders. The lead author was Gary Wayman of Washington State University's Program in Neuroscience, who first described the molecular pathway that controls the calcium signaling in the brain that guides normal dendrite growth.
Wayman found that key cellular players, called calcium and calmodulin kinases, are activated by increased calcium levels. Activated calmodulin kinase then turns on th
|Contact: Karen Finney|
University of California - Davis Health System