NEW INFORMATION ABOUT HOW NEURONS ACT COULD LEAD TO BRAIN DISORDER ADVANCEMENTS
Neurons are
electrically charged cells, located in the nervous system, that interpret and
transmit information using electrical and chemical signals. Now, researchers at
the University of Missouri have determined that individual neurons can react
differently to electrical signals at the molecular level and in different ways
-- even among neurons of the same type. This variability may be important in
discovering underlying problems associated with brain disorders and neural
diseases such as epilepsy.
"Genetic
mutations found in neurological disorders create imbalances in the inward and
outward flow of electrical current through cells," said David Schulz,
associate professor in the Division of Biological Sciences in the College of
Arts and Science and a researcher in the Interdisciplinary Neuroscience Program
at MU. "Often, neurons react to electrical signals, or voltage, and
compensate by altering their own electrical outputs. The variability in these
imbalances, even among multiple cells of the same kind within the brain, is one
of the major problems scientists face when trying to design therapeutics for
disorders like epilepsy. Seizures in individuals can be caused by different
imbalances -- therefore getting to the root of how neurons act individually
makes our studies important."
Schulz
and his team previously proved that two identical neurons can reach the same
electrical activity in different ways. In his new study, Schulz hypothesized
that neurons might use the cell's genetic code, or its messenger RNA (mRNA), to
"fine tune" the production of proteins, helping individual cells
react accordingly.
Using
clusters of neurons obtained from Jonah crabs, Schulz and his team
experimentally altered electrical input and output in the neurons and measured
the messenger RNA (mRNA) levels found within the cells. Invertebrates like
crabs are useful in neuroscience research because their neurons are simple
enough to observe and study, but advanced enough that they can be "scaled
up" to apply to higher organisms, Schulz said.
They
found that when normal patterns of stimulation were maintained, cells engaged
the correct ratios of mRNA to produce the proteins needed to help keep
electrical impulses in order; however, when normal patterns of activity were
not maintained, this fundamentally changed the cells at the molecular level.
"We
were the first to show that the correct ratios of mRNAs are actively maintained
by the actual activity or voltage of the cell, and not chemical feedback,"
Schulz said. "These results represent a novel aspect of regulation that
might be useful for developing therapeutics for neuronal disorders later."
Schulz'
study, "Activity-dependent feedback regulates correlated ion channel mRNA
levels in single identified motor neurons," was published in the August 18th edition ofCurrent Biology.
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