A team of researchers in Japan has successfully measured the voltage changes of the suprachiasmatic nucleus (SCN) over the days that could help maintaining the body's clock. SCN is a tissue formed from a network of thousands of neurons that act as the master circadian clock.
Researchers from Hokkaido University and other colleagues in Japan has measured voltage changes in SCN cells after previous methods show indirectness in measuring the neuronal activities or lacking spatial information, as stated in their study named "Synchronous circadian voltage rhythms with asynchronous calcium rhythms in the suprachiasmatic nucleus" published in PNAS. The SCN is responsible for generating daily rhythms in physiology and behavior like sleep patterns that helps the body clock.
The research team introduced a gene that encoded voltage sensors into cultured SCN slices from some newborn mice that were used in experiments for body clocks. These sensors were formed by fusing a fluorescent protein with another protein so that it could sense voltage. The intensity of the sensor's fluorescence changes was significant with the changes in voltage that was detected by a special microscope used by the research teams.
They were astonished to find out that the voltage rhythms were synchronized across the entire SCN, according to an article published in Science Daily. Ryosuke Enoki of Hokkaido University, the senior author of the study about body clocks, said that the result was unexpected because previous research found neuron groups in various SCN regions having circadian rhythm genes in various ways.
Enoki and his team also found that while measuring voltage changes, it is not synchronized with the entire SCN. They simultaneously measured calcium ion concentration on the cell membranes and found a similarity to the so-called "clock genes" that is relevant to the body clock.
It is suggested by their team that the SCN could maintain a network-wide coherent rhythm through synchronous voltage as linked to body clock. Neurons in the SCN could generate oscillatory signals that are sent out to various parts of the brain and other organs on the body.
"Intercellular interactions within the SCN could be in play in synchronizing voltage rhythms separate from asynchronous calcium rhythms," Enoki has said. He also said that further research is important in order to clear out the mechanism and its physiological roles in maintaining the circadian body clock.
