Curious: Presentations by Young Researchers II
Why Does a Hand Move When We Think of It?
Three young Japanese researchers in Chicago
made curious presentations about their studies at the Japan Information Center
of the Consulate General of Japan at Chicago on April 13.
Tomoya Kubota, Postdoctoral Scholar ? Department
of Biochemistry and Molecular Biology at the University of Chicago, spoke
about a process pinpointing the cause of nerve related disease.
Looking for a cause of specific symptom
When Kubota was in the Graduate School of Medicine, Osaka University, he encountered a patient who was suffering from myotonic disorder. He had enlarged muscles and was unable to open his hands quickly once he squeezed them. He said if he found a genetic anomaly, he couldn’t say that it was the cause of the disease because a gene had a complicated structure. A gene has exons, which become protein, and other areas. When exons get together, messenger RNA (mRNA), a blueprint copy of protein, is made, then protein is created, and cells, organs, and body are created step by step; therefore, he said that a process to find a cause is difficult.
In his patient’s case, action potential, which transmitted a signal to his muscles from his brain, was continuously firing. It was found by a test with a needle in his muscles.
What is action potential?
The Natrium (sodium) channel, Kalium (potassium) channel, and Chloride channel are responsible to transmit an electronic signal to muscles from a brain. Each of them has specificity, such as Na channel only transmits sodium, and K channel transmits almost only potassium. In this circumstance, the inside of a cell is kept as negative.
When you think that you want to move your
hand, an electronic signal reaches your muscle, and potential gradually rises
at the cell membrane of muscle. When the potential reaches a certain level,
Na channel suddenly opens and natrium (sodium) flows into the inside of a
cell. Then the inside of the cell turns to positive. The rise of potential
at cell membrane is called generation of action potential
Two causal genes of myotonic disorder have
been discovered. One is Na channel SCN4A, and another is Cl channel CLCN1.
Kubota analyzed the genes and found his patient’s had something wrong with
Na channel SCN4A. Further study found that the gene would have blueprints
for normal and abnormal protein, and their ratio was 2:1. However, he still
thought about if he could say that the abnormal protein was cause of the symptom.
Kubota said that his purpose of research
in Chicago was visualizing action potential, and he would approach it by measuring
energy transfer. He also said that he would like to make customized medicine
for each patient by finding the real cause of a disease.