The medical community is becoming more and more interested in the role retinas play in regulating our internal biological clock (aka our circadian rhythm). The reason for this interest has to do with a new study out of Scotland that shows how certain retinal cells are in direct communication with the part of the brain in charge of circadian rhythm.
Researchers at Edinburgh University found that the region of the brain that deals with circadian rhythm, known as the suprachiasmatic nucleus (SCN), interprets light information that passes through the retinal nerve fibers. Perhaps most importantly, scientists discovered that our retinas contain vasopressin-expressing cells that are exclusively concerned with communicating visual data to the SCN.
This study is especially important for people who frequently fly around the world. Vasopressin is the most important chemical in terms of re-setting our circadian rhythm to different time zones.
In order to find novel ways for combating the dreaded symptoms of "jet lag," Scottish professors took a group of lab rats and modified their vasopressin-expressing cells. One group of rats had their vasopressin-expressing cells destroyed, whereas the others had them activated.
While this study was designed just to better understand the workings of circadian rhythm, many of the researchers believe pharmaceutical companies could use information to develop new sleep aids. Specifically, researchers hope drug companies could develop eye drops to effectively combat the symptoms of jet lag.
Mark Ludwig, a professor of neurophysiology at the University of Edinburgh, told researchers that his team's study results "show a potentially new pharmacological route to manipulate our internal biological clocks." Although no new drug came out of this study, Dr. Ludwig is hopeful that future research into vasopressin will lead to revolutionary drugs designed for world travelers.
Interestingly, jet lag wasn't on the Scottish researchers' minds during this study. Everyone involved in this research was far more interested in how poor circadian rhythm could lead to other serious health problems, especially for people who have to work the late shift. It's well known that people who don't have a natural circadian rhythm have numerous physical and mental issues including depression, a higher risk of cancer, and a shorter life expectancy.
Jet lag (officially known as desynchronosis) is defined as a sleep disorder that affects people who travel between at least two different time zones in a relatively short span of time. Symptoms typically include insomnia, fatigue, headaches, and indigestion.
People deal with jet lag in different ways, but the most common methods include taking melatonin supplements, using a light box, and anticipating sleep pattern changes in advance by changing alarms and watches ahead of time. People who exercise regularly overcome jet lag symptoms with greater ease than those that don't. Avoiding all alcoholic and caffeinated beverages also helps re-calibrate the circadian rhythm.
There's no word yet on whether these jet lag eye drops will be developed anytime soon. Scientists still need to do more research on how vasopressin cells can be manipulated in the retina to safely change the signals they send to the brain.