> Scientists find origin of electrical signals in nerve cells
Scientists find origin of electrical signals in nerve cells
January 22, 2008
A long-standing controversy in scientific circles over where the electrical signal in nerve cells originates – information critical to understanding how nerve cells work and might be modified - appears to have been solved.
A team of scientists, among them, SFU kinesiologist Peter Ruben, says it has found conclusively that the signal originates in a nerve cell’s initial segment.
Some scientists have believed that electrical activity begins in the cell’s axon, a long projection from the body of the cell. The initial segment is located at the start of the axon, where it emerges from the cell body.
The findings of the team’s study, undertaken in research labs in Germany and Australia, are being reported this week (Jan. 21) in Nature Neuroscience’s online journal.
Ruben says the team is confident they now know where the electrical signal begins because the initial segment has the highest density of a particular protein, called the sodium channel, which is responsible for generating signals.
“Knowing that the highest density of sodium channels is in the axon’s initial segment means that it is the site of greatest sensitivity and determines whether or not a neuron (nerve cell) will become electrically active,” says Ruben, who studies the biophysical properties of sodium channels.
Ruben says knowing where electrical signals begin sheds a great deal more light on how nerve cells work, particularly in terms of their role in learning and memory, and how they might be modified by pharmaceutical agents to effect such conditions as epilepsy.
“If the sensitivity of these channels is modified, then the probability of a neuron being electrically active and generating a signal, either individually to begin a process, like movement, or as a link in a chain of events, such as a reflex, may be most easily modified at this location,” Ruben notes.
“This is research at its most basic level,” says Ruben, who is also director of SFU’s School of Kinesiology. “The controversy has gone on for a long time…this puts several nails in the coffin.”
A team of scientists, among them, SFU kinesiologist Peter Ruben, says it has found conclusively that the signal originates in a nerve cell’s initial segment.
Some scientists have believed that electrical activity begins in the cell’s axon, a long projection from the body of the cell. The initial segment is located at the start of the axon, where it emerges from the cell body.
The findings of the team’s study, undertaken in research labs in Germany and Australia, are being reported this week (Jan. 21) in Nature Neuroscience’s online journal.
Ruben says the team is confident they now know where the electrical signal begins because the initial segment has the highest density of a particular protein, called the sodium channel, which is responsible for generating signals.
“Knowing that the highest density of sodium channels is in the axon’s initial segment means that it is the site of greatest sensitivity and determines whether or not a neuron (nerve cell) will become electrically active,” says Ruben, who studies the biophysical properties of sodium channels.
Ruben says knowing where electrical signals begin sheds a great deal more light on how nerve cells work, particularly in terms of their role in learning and memory, and how they might be modified by pharmaceutical agents to effect such conditions as epilepsy.
“If the sensitivity of these channels is modified, then the probability of a neuron being electrically active and generating a signal, either individually to begin a process, like movement, or as a link in a chain of events, such as a reflex, may be most easily modified at this location,” Ruben notes.
“This is research at its most basic level,” says Ruben, who is also director of SFU’s School of Kinesiology. “The controversy has gone on for a long time…this puts several nails in the coffin.”