Could more deep sleep be the solution to insomnia? Investigators have toyed with the idea for years. People with insomnia tend not to get as much deep, or slow-wave, sleep as normal sleepers. Finding a way to prolong slow-wave sleep might make our sleep feel sounder and more restorative.
Last week’s discovery of a sleep node in the brainstem associated with the initiation of slow-wave sleep is promising news in this regard. Not only does it point to a new target for treatment. The procedure scientists at Harvard Medical School and University at Buffalo School of Medicine and Biomedical Sciences used to obtain their results suggests that the possibility of altering sleep via genetic modification may not be as remote as it sounds.
A Look at the Research
These researchers set out to study an area deep in the brainstem of humans and other mammals. It’s located in the medullary parafacial zone, or PZ. The PZ contains neurons that produce GABA, the main neurotransmitter responsible for calming the brain at night. These neurons are always active during normal slow-wave sleep.
They wanted to find out whether simply activating these neurons would induce slow-wave sleep in mice, and they used a novel protocol to find out. Rather than stimulating the GABA neurons with electrodes, a process that disturbs surrounding neurons, they targeted the GABA neurons by altering a gene.
“To get the precision required for these experiments,” said Patrick Fuller, senior author of the paper, “we introduced a virus into the PZ that expressed a ‘designer’ receptor on GABA neurons only but didn’t otherwise alter brain function.” Using innovative tools that enabled them to control the GABA neurons remotely, they turned the neurons on.
The result? The mice fell quickly into a deep sleep—as if they’d been knocked out with a sedative. But no sleep medication was involved.
The ability to induce slow-wave sleep by means of a single genetic modification is an encouraging development. “We are at a truly transformative point in neuroscience,” said Caroline E. Bass, co-author of the paper, “where the use of designer genes gives us unprecedented ability to control the brain.”
Other Treatments That Enhance Deep Sleep
Scientists have worked to develop other therapies that boost slow-wave sleep. But none are available for people with insomnia.
- Development of sleep medications such as eplivanserin and pimavanserin was abandoned due to concerns about safety and side effects.
- Transcranial magnetic stimulation (TMS)–a treatment in which an instrument sends a harmless magnetic signal through the scalp and skull into the brain, activating electrical impulses and inducing slow waves–is currently approved for the treatment of depression. Some studies have suggested that TMS is helpful in treating insomnia, and a clinical trial of TMS for insomnia is now under way at the University of Florida. But it hasn’t been approved as a therapy for insomnia yet.
Which brings us back to designer genes that modify sleep. I’ve always thought they were pie in the sky for my generation. But the results of this experiment suggest they may become a reality sooner than I thought.