Researchers have found a new neural pathway that links the circadian clock, stress, and wakefulness in mammals.
A Nagoya University-led research team in Japan has found a new neural pathway that links the circadian clock, stress, and wakefulness in mammals. The team identified a neuron, called the corticotropin-releasing factor (CRF) neuron, that becomes excessively active when the mammal is under stress, which could trigger insomnia and other sleep disorders. Their findings were recently published in the journal Science Advances.
Living organisms exhibit a 24-hour oscillation called the circadian rhythm. In mammals, the central circadian clock, located in the brain’s suprachiasmatic nucleus (SCN) neurons, regulates the sleep-wake cycle. However, in the event of life-threatening situations, the circadian rhythm signal is shut off to keep the animal awake so that it can escape from danger even when it would normally be time to sleep. Although the temporary shutoff of the sleep-wake cycle is necessary for survival, excessive or prolonged stress caused by such dangers can trigger insomnia and other sleep disorders.
“It is well-known that the circadian clock and stress have an effect on sleep, but it was unclear which neural pathway is crucial for the circadian regulation of sleep and wakefulness,” says Dr. Daisuke Ono of the Research Institute of Environmental Medicine at Nagoya University. To determine the pathway, a Nagoya University research team led by Prof. Akihiro Yamanaka and Dr. Ono, in collaboration with Takashi Sugiyama at Olympus Corporation in Japan, conducted a study using mice