Be calm

 作者:疏锣     |      日期:2019-03-08 07:05:25
By Nell Boyce A GENETIC switch insects use to control moulting is helping a team of researchers to calm excited nerve cells. Their method may soon yield new treatments for epilepsy and chronic pain. In some disorders, such as epilepsy, nerve cells become overactive and respond to electrical signals even when they are below the usual threshold for action. In the past few years, however, scientists have identified “silencing” genes in brain tissue which suppress the activity of nerve cells by creating extra potassium channels in the cell membrane. An influx of potassium can alter the electrical charge and raise the firing threshold. Now David Johns and his colleagues at the Johns Hopkins University in Baltimore, Maryland, have used a silencing gene to control the activity of nerve cells in cultures of rat spinal tissue. When they shuttled the gene into the cells, they stopped firing within one to two days. But doctors treating neurological diseases would not want to completely suppress nerve responses. So Johns and his colleagues linked the silencing gene to a another gene that controls moulting in fruit flies before inserting it into the cultured nerve cells. This enabled them to control the level of firing by applying different levels of the insect hormone muristerone, which activates the fruit-fly gene (The Journal of Neuroscience, vol 19, p 1691). “We can get in there and turn on as much as we need,” says Johns. Within the next few weeks,