Exposure to lead wreaks havoc in the brain, with consequences thatinclude lower IQ and reduced potential for learning. But theprecise mechanism by which lead alters nerve cells in the brain haslargely remained unknown. New research led by Tom s R. Guilarte, PhD, Leon Hess Professorand Chair of Environmental Health Sciences at Columbia UniversityMailman School of Public Health, and post-doctoral researchscientist Kirstie H. Stansfield, PhD, used high-powered fluorescentmicroscopy and other advanced techniques to painstakingly chart thevaried ways lead inflicts its damage. They focused on signalingpathways involved in the production of brain-derived neurotropicfactor, or BDNF, a chemical critical to the creation of newsynapses in the hippocampus, the brain's center for memory andlearning. The study appears online in the journal Toxicological Sciences. Once BDNF is produced in the nucleus, explains Dr. Stansfield, itis transported as cargo in a railroad-car-like vesicle along atrack called a microtubule toward sites of release in the axon anddendritic spines. Vesicle navigation is controlled in part throughactivation (phosphorylation) of the huntingtin protein, which asits name suggests, was first identified through research into Huntington's disease . By looking at huntingtin expression, the researchers found thatlead exposure, even in small amounts, is likely to impede orreverse the train by altering phosphorylation at a specific aminoacid. The BDNF vesicle transport slowdown is just one of a variety ofways that lead impedes BDNF's function. The researchers alsoexplored how lead curbs production of BDNF in the cell nucleus. Onefactor, they say, may be a protein called methyl CpG bindingprotein 2, or MeCP2, which has been linked with RETT syndrome and autism spectrum disorders and acts to "silence" BDNF gene transcription. The paper provides the first comprehensive working model of theways by which lead exposure impairs synapse development andfunction. "Lead attacks the most fundamental aspect of the brain -the synapse. But by better understanding the numerous and complexways this happens we will be better able to develop therapies thatameliorate the damage," says Dr. Guilarte. Additional References Citations. I am an expert from auto-drivebelts.com, while we provides the quality product, such as Brake Disc Replacement Manufacturer , China Timing Belt Pulleys, Car Timing Belts,and more.
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